Hope you enjoy it as much as I will.

The post LIVE Building Event: The Tower of Orthanc appeared first on The Technic Gear.

Before I start I have to say that I have been surprised. To be fair, I completely ruled out this Speed Champions range because prices are too high for what I expected. But after building it, I have to agree that the sets are a bit overpriced ( as most LEGO are ) but still interesting. And quite enjoyable.

So, let’s review it and see if there is a happy father and a happy son after this $100 LEGO.

Model data

Name F14 T & Scuderia Ferrari Truck
Ref. Code 75913
Theme Speed Champions
Year 2015
Parts 884
Price £79.99
Minifigs 6
Where can I buy LEGO 75913 Ferrari Truck?
Check at Brick Marketplace, they have a 5% off all the Summer.

Model background

Transport the iconic Scuderia Ferrari team to the race track!

Drive the Scuderia Ferrari team and F14 T race car to the circuit in the fully-equipped Scuderia Ferrari truck. Open up the roof of the cabin to place the truck driver at the steering wheel with a team crew member alongside. Detach the trailer and turn the lever to release the standing feet. Fold out the roof and sides to access the awesome race car, scooter and array of cool equipment including a complete tool set and computer screens. Lower the rear hatch and activate the launch function to push the F14 T down the ramp.

Then challenge your friends and their LEGO Speed Champions cars to thrilling races! Includes 6 minifigures with assorted accessories: a driver, team truck driver and 4 team crew members.

Model Box

The box is quite big… and to be fair, I had the feeling that this set was a rip off but the amount of parts is quite nice.

And this is the back part of the box.

You really can’t make an idea about how big this set is compared with other LEGO trucks.

Manuals

All the set is built with a single book that it is quite long… for storage it is great because I can’t figure a decent way of storing manuals but for building I think I prefer several smaller booklets. Almost 200 A4 pages.

Building experience

And well, the interesting part. Is it fun to build? Yeah. It doesn’t have anything awesome but it is still an interesting set to build. Perhaps the most cool parts are the frontal truck side and the opening roofs as well as the retractable ramp.

This is the speedbuild video & review of the Ferrari Scuderia Truck

Complete model

F1 Race Car

The Ferrari F14 T is quite well done. Again, it is built in a different scale of other LEGO cars, but the result is quite good.

It is quite fun that you can detach the front nose and the wheels pretty much like in a F1 car.

Also the minifigs come with all the tools you need to do a perfect lap!

Truck

The truck is HUGE.

The cabin is wonderfully donde with lot of attentions to details. And with lots of stickers. In fact, this set has two sheets of stickers… so I hope you enjoy them :)

This is the back part of the cabin.

Inside of the truck there is room for the car, a scooter, toolsets and several computers… as well as an extra F! nose and two wheels.

On the computers you can check all the car telemetry details and make the best time :)

And using the ramp you can push your car to the racing circuit.

Minifigs

This set comes with 6 Ferrari branded minifigures.

And these are the two toolbox for all your F1 repair needs.

And to move your driver to the startig position what could be better than a fantastic red scooter.

Overview

Miguel says 7/10

Building experience
Value for money
Playability
Parts

Pros

– The truck is huge: 41cm of truck!
– The set comes with lots of details.
– The F1 car looks great.

Cons

– Expensive.
– Perhaps too simple to build.

Does LEGO 75913 worth the money?

Ummm… it is a hard question. Personally I think it is crazy expensive, and after building it I see it has lots of parts and details… but still it is over 100€and that’s quite expensive. If you are a die-hard fan of Ferrari it will be a great set but if you are just looking for a fun LEGO truck I think you should check others, more affordable, options. In any case, check it at Brick Marketplace, they have a 5% off all the Summer.

The post LEGO 75913 Ferrari F14 T & Scuderia Ferrari Truck Review appeared first on The Technic Gear.

This set is a two stories building with a great roof and lots of awesome details inside. Let’s review it.

Model data

Name Palace Cinema
Ref. Code 10232
Theme LEGO Creator
Year 2013
Parts 2196
Price £119.99
Minifigs 6
Where can I buy LEGO 10232?
Amazon

Model background

Build a grand premiere at the Palace Cinema!

It’s premiere night at the Palace Cinema! Illuminate the night sky with the spotlights as the child star arrives in a fancy black limousine! Gather the crowd on the star-studded sidewalk, then head into the detailed lobby with a concession stand and ticket area! Take the grand staircase into the theater with a large screen, movie projector and reclining chairs for 6 minifigures.

Introducing the latest addition to the LEGO® Modular Buildings series, the highly detailed, 2-story Palace Cinema corner building. This collectible model features a sidewalk of the stars, brick-built entrance doors, posters, sign frontage, a tower with spires and rooftop decorations. Includes 6 minifigures: child actress, chauffeur, female guest, male guest, photographer and cinema worker.

Model Box

As it is usual with all the expensive LEGO sets this Palace Cinema comes in a huge box. This is the front view

And this is the back view that highlight some of the most interesting parts.

Here you have an unboxing video, so you can get an idea of what it is inside the box.

Manuals

Like all the LEGO Creator experts sets it is not how many manuals it has, but how detailed each step is.
This set comes with three manuals and a good five or six hours of non-stop building.

Building experience

This is a very interesting set to build. Most of the exciting action happens on the bottom floor and the root. I enjoyed the roog and the little details of the bottom floor.

It isn’t hard to build but it is a bit boring while builing layer after layer of walls. The second floor is the one i enjoyed less building it.

Here you have a speed build and review of the Palace Cinema

Complete model

So here is the complete model.

Let’s see each detail because some of them are really lovely.

This is the main door with some of the minifigs and the huge lights that illuminate the building.

And everything is ready for VIPs to come. Photograph included.

The limousine looks classy. And pretty much does the work.

This is one corner of the main floor where the popcorn shop is located.

And don’t miss the details of the main door to enter the Palace Cinema.

As well as the posters advertising new movies to come. The films’ titles are simply hilarious.

The sign frontage is a pleasure to build and one of the things that makes this model so interesting and personal.

You can see the side of the Palace sign frontage. I really love the way of using LEGO parts to actually write text. And of course, don’t miss the roof.

This is the roof that has a trapdoor to access to it from the second floor.

And this is the the cinema itself.

With a HD projector :)

These are the minifigs that come with the Palace Cinema set.

Overview

Miguel says 9.5/10

Building experience
Value for money
Playability
Parts

Pros

– A fantastic set with lots of personality
– Limousine included.
– Huge
– The roof looks awesome

Cons

– The second floor is a bit boring to build
– Price?

Does LEGO 10232 worth the money?

Definively. I love LEGO modulars, so I would say that it is money well spent. Check Amazon for a nice discount.

The post LEGO 10232 Palace Cinema Review appeared first on The Technic Gear.

I have been delaying this too much, waiting for the perfect moment, for the perfect light, for the right mood, and I have realized that nothing is perfect so…. I build. I love to record timelapse videos of all the building process, unfortunately this kind of videos require proper light and a time to build it from begin to end without interruption and right now I don’t have any of them.

Model data

Name Customized Pick-Up
Ref. Code 42029
Theme LEGO Technic
Year 2014
Parts 1063
Price £69.99
Minifigs 0
Where can I buy LEGO 42029?
Amazon

Model background

Transport heavy loads over rough terrain with the giant, red Pick Up Truck! This rugged vehicle has huge wheels, a robust chassis, fully independent suspension, a large V-6 engine, sturdy grill guard with winch and a tipping bed.

You can rebuilds it into an awesome Forest Skidder.

Model Box

This set comes in a big box, not as big as the Mobile Crane or the 4×4 Crawler but big enough. The front side shows the picku-up model

And the back side shows the main features as well as the model B.

Manuals

This sets comes with 3 instructions manuals to build it. The steps are quite straight forward to follow. The last booklet has a section to add powerfunctions to operate the back part of the pickup and the front crane.

Building experience

After so much time ( my last Technic model was the Service Truck ) it has been a real pleasure to build Technic again, and not having to record the whole process allowed me to really enjoy each step.

The building is quite straight forward, first building the chassis, then the front part of the cabin and finally the storage section on the back of the vehicle. I would swear there is still enough room for properly motorizing it without big modifications on the lower part of the chassis.

Complete model

This is the complete model.

And here you have a short video review

This is the back part of the car.

Here you can see the frontal crane that it is operated with a small gear on the side ( unless you add the optional Power Function set and you can run it with a M-motor )

Watching this beauty from the underside… you are looking the differential and the springs. I don’t get tired of looking at it.

Close-up hood details…

And under the hood…

Overview

Miguel says 9.5/10

Building experience
Value for money
Playability
Parts

Pros

– Nice, straight forward LEGO Technic building process
– It is really nice when finished
– A good way of learning more

Cons

– An IR Controller would have been too much to ask for?

Does LEGO 42029 worth the money?

Definitively! I really enjoyed building this set and if you pay attention to the building process you can learn a lot. I would really check an offer at Amazon. I got mine with £25 off.

The post LEGO 42029 PickUp Truck appeared first on The Technic Gear.

So let’s review it.

Model data

Name Tracked Excavator
Ref. Code 42006
Theme LEGO Technic
Year 2013
Parts 720
Price £49.99
Minifigs No
Where can I buy LEGO 42006?
Amazon

Model background

Build the ultra awesome Excavator, a LEGO® Technic construction site staple! This hard-working vehicle features lots of authentic details, including a working 4-prong grabber, articulated extending arm, rotating superstructure and moving tracks. Create a model that’s like the real thing! Motorize this cool construction vehicle with 8293 LEGO Power Functions Motor Set (sold separately). Rebuilds into a cross-country Tracked Tractor with raising/lowering rear and front tools, adjustable/detachable plow blades and an opening hood.

Model Box

This set comes in a decent box and well… despite being a LEGO Technic model it is reasonably full.

Manuals

The model B is built with three manuals that you can download from LEGO website. I use the iPad to read the manuals and build the model. I find it simpler and faster than actually printing the stuff…

Building experience

I have a kind heart for the 42006 Excavator because it was my first LEGO Technic model. I really love it because it is complex enough to build while at the same time can be done in a few hours without much stress: don’t get me wrong! I love the 42030 VOLVO Truck but I have to find a day with enough spare time to build it… same with the 42009 Mobile Crane MKII

If you want to introduce into LEGO Technic building, this set is simple fantastic for the experience you will rewarded with.

Complete model

This is the complete model.

Overview

Miguel says 9.5/10

Building experience
Value for money
Playability
Parts

Pros

– Everything!

Cons

– Lack of motors. It would have been great if this model had some instructions to motorize it using the LEGO remote control.

Does LEGO 42006 worth the money?

Definitively! I just love this set. And for sure Amazon has a price that makes the one at LEGO Shop looks like a bad joke.

Now I will take it apart and build again the model A and see if I can motorize it in a decent way.

The post LEGO 42006 Tracked Tractor Review appeared first on The Technic Gear.

Model data

Name Christmas Tree Truck
Ref. Code 40083
Theme Seasonal
Year 2013
Parts 118
Price Not for sale
Minifigs 1
Where can I buy LEGO 40083?
This set wasn’t available for sale. It was given to LEGO Shop VIP members for orders placed after Nov, 28 2013.
Anyway, you may be able to find it at Amazon

Model Box

In line with most of the small LEGO Set, a small box almost empty.

This is the back of the box.

Manuals

One instructions manual to build the car and the tree

Building experience

The model is easy to build and there is nothing specially challenging on it. Here you have the mandatory timelapse building.

Complete model

It works quite well for such an small set. The truck looks nice enough and the tree does the work.

Minifigs

The model has a minifig that is the truck’s driver. An old man with grey hair. Fair enough.

Overview

Miguel says 5.5/10

Building experience
Value for money
Playability
Parts

Does LEGO 40083 worth the money?

Well, I got it for free… so I have no opinion. You can buy it at Amazon for barely £10

The post LEGO 40083 Christmas Tree Truck Review appeared first on The Technic Gear.

If you like Batman and black LEGO parts this is your set. And I don’t want to spoil my own review, but the set isn’t so complex to build as I was expecting yet as delightful as you may think it is.

Model data

Name The Tumbler
Ref. Code 76023
Theme DC Comics Super Heroes
Year 2014
Parts 1869
Price £ 159.99
Minifigs 2
Where can I buy LEGO 76023?
Amazon ( But I would check LEGO Shop because it will be cheaper for sure )

Model background

Take on the challenge of building The Tumbler, an amazingly cool LEGO model of the iconic vehicle from the Batman The Dark Knight Trilogy. Construct this black armored vehicle highlighted with new colour LEGO elements and brand new LEGO front wheels. Check out the cool, detailed interior and adjustable top wings. Includes 2 new and exclusive minifigures: Batman and The Joker.

Model Box

The box is HUGE but I suppose it has to be when you pay €190 for a toy. The front side of the box features the Tumbler…

and the back side shows parts of the interior and other details. And this is the unboxing in case you want to see it.

Manuals

This sets comes with five scary instructions booklets. But once you read them, you realize that this is not like other LEGO Creator sets, in Batman Tumbler each step is a small change over the previous step and it is easy to build.

Building experience

I was expecting a very long building process but I have to say that I got it under four hours ( the mobile crane took me around six hours ) and the Tumbler looks like Tumbler pretty early on the building steps.

First you build the floor of the Tumbler using studded Technic parts and then you continue developing the chassis of the car that will hold all the external decorations.

I really love the way of attaching parts to create impossible angles and the way back wheels are joined so they look like the real Tumbler.

Complete model

This is the complete model

Here is the backside of the Tumbler where you can see the double wheel system.

This is a side view of the car. Just look at the huge amount of details it has.

LEGO also placed a lot of care while designing the interior of the Tumbler

And finally one of the nicest parts are the front wheels that although don’t steer like the original Tumbler are quite solid and looks awesome.

Here you have a short video review of the model.

Minifigures

This set comes with a special stand to place to special minifigures: a black Batman and the Joker.

Overview

Miguel says 10/10

Building experience
Value for money
Playability
Parts

Pros

– This is awesome.
– The car is really big

Cons

– It is really fragile.
– Don’t expect it to steer :)

Does LEGO 76023 worth the money?

I would buy it again eyes closed, but I have to agree that it is expensive and it isn’t much of a toy. Just handling the Tumbler to take a few pictures made some of the parts to detach. But again… it is a impressive vehicle.

The post LEGO 76023 Batman’s Tumbler UCS Review appeared first on The Technic Gear.

Good things, bad things. Unfortunately my LEGO tower grows and grows and grows, so I either wait for free time to record properly the timelapse building of the sets or I just go on and build them and just live without the timelapse. I would love to listen to you, does anyone really enjoy them so much? I hate winter.

The post LEGO Christmas Presents appeared first on The Technic Gear.

I have been wanting to build a big ( bigger I mean! ) LEGO Train tracks since this Summer but things have been turning wrong in everyway they can get wrong… so it hasn’t been till a few days ago that I was able to get me and the kids to build it. Here is the video.

This track include several all-times favorites and I am not talking about the exciting AT-AT but of:

• The DIY x-cross track
• The 2014 New train station
• the 2014 Passengers Train and the 2014 Cargo Train
• The infamous motorized points track

If you liked this video, don’t miss a smaller but more challenging to build one, with slopes and two levels.

Like? Please share.

The post One LEGO Train to rule them all appeared first on The Technic Gear.

Let’s review it.

Model data

NameAvengers: Captain America vs Hydra
Ref. Code 76017
Theme Marvel Super Heroes
Year 2014
Parts 172
Price £19.99
Minifigs 3
Where can I buy LEGO 76017?
Amazon

Model background

The evil Red Skull has seized the cosmic cube and is bringing chaos to the world in the rugged Hydra off-road vehicle with working suspension wheels, rotating turret, and dual flick missiles.

Hop on the motorcycle and race Captain America to the rescue! Will he be able to disarm it using his impenetrable shield and recover the cosmic cube? This playset includes three minifigures with assorted accessories: Captain America, Red Skull, and a Hydra henchman.

Model Box

This is a small LEGO box but as usual it is half empty.
This is the front side.

This is the back side.

Manuals

It is a simple set so it has just one booklet.

Building experience

This set is mainly about building the tank, it is really nice to see how they designed the suspension using LEGO parts. I have seems similar tricks on LEGO Technic but here the concept is simply lovely because there are no eye candies.

Here is the video review and the timelapse building.

Complete model

This is the complete model.

Captain America’s Bike

Close to nothing to build here but the bike looks awesome. I really love this little Captain America with his shield riding it.

Hydra’s Tank

This is the Hydra tank and it looks quite nice ( if you are able to forget about this WWII tanks that I have seen ).

This is the suspension working

Minifigs

And well, the best part of the set in my honest opinion… the minifigs.

Overview

Miguel says 9/10

Building experience
Value for money
Playability
Parts

Pros

– Wooa! Just look at that like Cpt. America!
– The tank moves in a hypnothnic way.

Cons

– The tank is a bit simple

Does LEGO 76017 worth the money?

I would say that it does! I got it at Amazon for £10 off over the retail price!

The post LEGO Avengers: Captain America vs Hydra Review appeared first on The Technic Gear.

This set is perhaps one of the best I have built in the last months. You won’t really believe that it can be done with the parts supplied on the bags.

Model data

Name Exo-suit
Ref. Code 21109
Theme Ideas
Year 2014
Parts 321
Price £29.99
Minifigs 2
Where can I buy LEGO 21109?
Amazon

Model background

Go on a mission to discover the amazing Exo Suit!

Put on your spacesuit and head out with Pete, Yve and their robot turtle on a mission to discover the long-lost Exo Suit! Selected by LEGO® Ideas members (formerly known as CUUSOO), this amazing model first appeared in the unofficial book, LEGO Space, written by LEGO fan and builder, Peter Reid. Featuring posable limbs, opening cockpit, grabbing claws and an intricate, modular form that you can tune to suit the most challenging missions, this amazing Exo Suit captures the essence of Classic Space design – and for the first time in 30 years, we’ve kitted Pete and Yve out in green spacesuits with the Classic Space logo! This set also includes building instructions and a fun booklet containing a cool space-themed story featuring the models and minifigures from the set, plus information about the creator. Includes 2 astronaut minifigures.

Model Box

As all the LEGO Ideas sets it comes in a small box but it is pretty full and comes with a precious manual.

Here is backside of the box.

Manuals

This set comes with a single manual but it is a precious big one.

Building experience

This is a fucking awesome great model! One of the very best building experiences I have had. It is simple crazy when you open the bags and the bigger part you can see is a 1×4 plate.

Here is the timelapse building.

Complete model

The model is quite fragile but absolutely gorgeous.

The Exo suit

This exo suit as I told you is simply fantastic. I love the way it moves the arms and the legs. And really it is amazing how it is built.

This is a detail of the leg

This is a detail of the arm

And here is the back of the exosuit

Robotic dog & platform

This is a lovely companion of the exo suit and two yellow containers.

Minifigures

This set comes with two minifigures: a man and a a woman with green astronaut suits.

Overview

So here is my review!

Miguel says 10/10

Building experience
Value for money
Playability
Parts

Pros

– Damn awesome set! Go! Get one!

Cons

– It is a bit complex to build. But it is part of the fun.

Does LEGO 21109 worth the money?

E-v-e-r-y-s-i-n-g-l-e-p-e-n-c-e of it! Go buy one ( if you can find it ). Amazon has some from their marketplace.

The post LEGO Ideas 21109 Exo Suit Review appeared first on The Technic Gear.

If you follow The Technic Gear you may recall that I built something quite close a few months ago. I will compare this LEGO model with what I built using it as a reference.

Model data

Name Train Station
Ref. Code 60050
Theme City Trains
Year 2014
Parts 423
Price £49.99
Minifigs 5
Where can I buy LEGO 60050?
Amazon

Model background

Browse the shops while you wait at the busy LEGO City Train Station!

Take a taxi to the busy LEGO City Train Station, a place that never sleeps! On arrival, go up the stairs and through the opening doors. Check the time on the large clock hanging from the roof and the map of train services by the ATM. While you wait for your train, browse around the shop selling LEGO® City products. Feeling hungry? Head to the kiosk and order a croissant or pizza and a drink from the menu signs hanging above the desk. Then take a seat on the clean platform, enjoy your snack and relax. Includes 5 minifigures: conductor, chef, taxi driver and 2 travelers.

Model Box

Not as big as the LEGO Train boxes, this Train Station comes with a decent box that as usual is almost empty.

On the back of the box you have lots of images of the station as well as that lovely diorama of LEGO Trains. I must try to build it someday.

Manuals

This set comes with three manuals. One to build the taxi and two to build the station.

Building experience

This set has a decent amount of parts but it won’t suppose a challenge to you. In fact when I built my own version of this LEGO Train station I used more parts to build the walls.

The set is big ( for so little parts ) and as usual you have here the compulsory timelapse building.

Complete model

Here is the complete model.

Taxi

The taxi is very similar to the old Train station’s taxi. Personally I don’t like at all the fact that both cars are one minifig-wide.

Train station

The train station has three different parts. On the right, there is a restaurant with a chef and something that looks like pizza… definitively the chef should be fired!.

On the left, there is a LEGO shop with several LEGO boxes. The result is quite interesting.

This is the train station from the left side

and this is from its right side.

Minifigs

This set comes with four minifigs: One taxi driver, a man, a woman and the Station chief.

Overview

It is a pretty decent set and big enough for its price.

Miguel says 9.5/10

Building experience
Value for money
Playability
Parts

Pros

– It is huge
– It has a decent price ( for a LEGO Set )
– It is easy to build

Cons

– Once you built a few LEGO Creator sets this one is a bit simple.

Does LEGO 60050 worth the money?

Definitively! Go and check on Amazon first, as you will save a few pounds.

The post LEGO 60050 New Train Station 2014 Review appeared first on The Technic Gear.

Minecraft is a open world game with a really ugly 8 bit graphics. Imagine Minecraft as the digital version of LEGO on steroids… just crazy awesomeness in barely 50MB of download. I started playing it and instantly fell in love with Minecraft.

So when I saw the LEGO Cuusoo/Ideas version of Minecraft I decided to buy it. And here is the review for you. Right now LEGO is releasing a “proper” Minecraft sets line, and I will review one of them really soon.

Model data

Name Minecraft Micro World: The Forest
Ref. Code 21102
Theme Cuuscoo/Ideas
Year 2012
Parts 480
Price £34.99
Minifigs 2 ( Microfigs )
Where can I buy LEGO 22102?
Amazon

Model background

Create, explore and play in a Minecraft microbuild!

Build a mini model of the game that’s sweeping the Internet with a LEGO® microbuild version of Minecraft! Selected by LEGO CUUSOO members, this build features a cool design with lots of 1×1 LEGO tiles and 2 buildable Micromob characters: Steve and Creeper.

Model Box

In a pretty nice homage to Minecraft the box departs of the standard LEGO boxes size and this one is an square block with a printed pattern that resembles that of a Minecraft grass block.

Manuals

Comes with two manuals that instructs how to build each of the 8 blocks that made this set.

Building experience

It is a quite interesting building and quite different to other LEGO sets. This set makes an extensive usage of 1×1 plates and bricks making it really extenuating to build it… and that’s really part of the fun :D

I have had a lot of fun building this. Here is the timelapse building

Complete model

This is the complete model.

It is is made with four different base blocks that has a dungeon with some water and lava and them over it you have a little house and a mountain with two trees. If you have played Minecraft you will know this is pretty much the first night setup :)

It has to micro-figures of Steve and a Creeper.

Overview

Miguel says 10/10

Building experience
Value for money
Playability
Parts

Pros

– I love it!

Cons

– Careful with your fingers :)

Does LEGO 22102 worth the money?

Every single pence you pay of it… given that you pay no more than £35 for it. Check Amazon for a bargain.

The post LEGO Cuusoo 21102 Minecraft The Forest appeared first on The Technic Gear.

Well, LEGO said a few years ago that they replaced the old 9V tracks by the actual plastic stuff because it would allow new vibrant track designs. #bullshit More than five years after that we still have exactly the same type of tracks geometry. We would love to see different size straight tracks and a wider curved tracks… but it looks like we will have to wait more.

But today let me share with you the fantastic work of Michael Skaako: A remotely operated switch track or a motorized point.

Even on the small tracks that I build on my house, it is really stressing to change switches fast enough when you have several trains running on the tracks. This little add-on built purely on LEGO parts will help you a lot.

These are the parts you are going to need

And this is HOWTO build it.

You can pay a visit to Skaako’s Flickr here

I hope to find the time to build a proper track that features this interesting addition. What would you built with it?

The post HOWTO Create a LEGO Motorized Train Points Track appeared first on The Technic Gear.

You can never get it wrong with Batman!

Model data

Name The Bat vs Bane: Tumbler Chase
Ref. Code 76001
Theme DC Comics
Year 2013
Parts 368
Price £39.99
Minifigs 3
Where can I buy LEGO 76001?
Amazon

Model background

Launch an assault from the sky to rescue Commissioner Gordon from Bane!

High above Gotham City, Batman™ spots Bane in the armored Tumbler chasing Police Commissioner Gordon. Bust through the road barricades in the Bane Tumbler with hidden dual flick missiles and flame exhaust. Then swoop down from the skies in The Bat and winch the commissioner to safety with the rescue rope before Bane reaches him! Includes 3 minifigures: Batman, Bane and Police Commissioner Gordon with assorted weapons.

Model Box

The box is moderately full… pretty much like all of these size for a LEGO set.
This is the front side.

And this is the back side of the box.

Manuals

The set comes with two small manuals.

Building experience

It is a pretty interesting experience to build this set. The Tumbler looks quite good and it is really solid. But perhaps the most interesting part is the Bat that it is quite more complex to build and has some interesting techniques to attach the engines to it.

Complete model

This is the complete model.

The Bat

It cames in black color ( no, it is not a very dark grey! ) and it is a really cool model with a few interesting techniques to build it. It features two big fans that works pretty much like engines and a windowed cockpit for your favorite superhero.

The Tumbler

Featuring a beige color, the Bane’s tumbler is really nice ( and as cool as the Batman’s one but still pretty cool ).

Minifigs

This set comes with three minifigs, Batman in a dark grey suit, Bane and Police Commissioner Gordon.

Overview

So here is my score.

Miguel says 8.5/10

Building experience
Value for money
Playability
Parts

It is a nice set and definitively a must-have if you are a die-hard Batman fan.

Pros

– It looks awesome.
– Exclusive Bane minifig

Cons

– The Bat doesn’t fly.
– Batman comes with no black suit.

Does LEGO 76001 worth the money?

Definitively! Check at Amazon for a bargain or have a look at the LEGO Shop if you are desperate.

The post LEGO 76001 The Bat vs Bane: Tumbler Chase Review appeared first on The Technic Gear.

I have had a really different summer and unfortunately I haven’t had the time I was hoping to have for building LEGO ( or anything else in fact )… but it is time to move forward so expect on the following weeks a few of these beauties reviews, the Montecarlo tutorial for the EV3 differential robot and trains! It is good to be back.

The post Back to LEGO Building & Reviewing appeared first on The Technic Gear.

Let’s review it.

Model data

Name Cargo Train
Ref. Code 60052
Theme LEGO City
Year 2014
Parts 888
Price £139.99
Minifigs 4
Where can I buy LEGO 60052?
As with the 60051 I got it from Amazon at a quite good price over the LEGO Shop.

Model background

Move heavy goods – and animals! – around the city with the super-powerful LEGO® City Cargo Train!

This awesome motorized train with 8-channel, 7-speed infrared remote control can transport almost anything. So it’s your job to make sure the cargo is in the right place at the right time to keep the city running smoothly.

Attach the cattle wagon and 2 cargo wagons together and pull them around the circular rail track with the locomotive. Operate the forklift to move the pallets safely between the wagons and truck. Keep track of all the cargo leaving and arriving in the office at the impressive cargo train station. There you can use the sliding overhead crane with hook to move heavy cargo between vehicles or onto the ground. With so many play functions and cool features, this really is the ultimate set for train enthusiasts!

Includes 4 minifigures: forklift driver, train driver, farmer and a truck driver.

Model Box

This model has a bigger box than the 60051 but pretty much like it, it isn’t full at all.

Manuals

This set comes with manuals to build the truck, the locomotive and all the train cars, as wheel as two manuals for the huge crane to take things off the car.

Building experience

Well, pretty much like the 60051, this LEGO Train is a pleasure to build. You can get it done in barely a one hour and a half with no stress. And there is a real focus on keeping the set simple.

Comparing this set to the Horizon Express, you realize how simpler is it. But the results are still impressive.

Perhaps the most interesting part to build is the crane.
Here you have the timelapse building.

Complete model

Well, here is the complete model

Locomotive

The locomotive is really nice, resembling those american freight trains and I say that it looks quite similar to the Maersk locomotive…

And here is photo from the other side

Cattle wagon

This wagon is lovely. It has a cow and a farmer that is milking it, it even has a buck full of milk.

Cargo wagons

There are two cargo wagons, one with huge green cable…

… and another with a gas tank and a forklift

Truck & Forklift

The truck won’t shake your world but it is nicely done.

The forklift on the other hand is quite fragile, so handle it with care. It is decent but I think I prefer the one in the 60020 Cargo Truck.

Tracks

Although this set comes with more tracks than the cheaper 60051 Passenger Train, it still has too few to build anything fun. At least it has two points tracks and 20 curved tracks as well as eight straight tracks.

My advise is go and get a few more.

Crane

The crane is big and impressive and it works quite well.

Overview

Miguel says 9/10

Building experience
Value for money
Playability
Parts

Pros

– Nice locomotive
– Easy to build
– The Crane is spectacular

Cons

– Too expensive

Does LEGO 60052 worth the money?

If you are reading this, maybe it is but… man… it is so expensive. I would go and check Amazon for a bargain and save a few bucks.

The post LEGO 60052 Cargo Train Review appeared first on The Technic Gear.

Time to review! By the way, I haven’t bought yet the 60050 Train Station but you can see a MOC I did based on it, as well as my own version LDD file ( with PDF instructions ).

Model data

Name Passenger Train
Ref. Code 60051
Theme LEGO City
Year 2014
Parts 610
Price £99.99
Minifigs 3
Where can I buy LEGO 60051?
I bought mine at Amazon because it was already on release 15€ cheaper than at LEGO Shop.

Model background

Travel around the city in no time with the motorized LEGO® City High-speed Passenger Train!

Operate the 8-channel, 7-speed infrared remote control to power around the curved tracks at top speed.

This streamlined, super-efficient train has a high-speed front profile and electricity contact points on top. Lift off the roof of the front car to place the driver inside at the cool dashboard and open the passenger cars to access the seats and tables. Wait for the train with the traveler at the way station, and pedal safely across the crossing with the cyclist once the train has gone past. Includes 3 minifigures: train driver, traveler and a cyclist.

Model Box

This set comes in a big box that contains all the parts and the tracks. As with most big LEGO boxes I am not totally sure you are getting what you paid for…
This is the front side of the box

Manuals

This set comes with four instructions manuals, one to build the little station and the rail crossing and the other three to build the train.

Building experience

After building a few LEGO Advanced models on a row ( I have right now the Townhall in mind… ), this set is quite easy to build. No exotic techniques, a reasonable number of parts and some new parts.

If you see the photos, you will realize that the front of the locomotive is a single big plastic piece. This could have been done with LEGO parts instead but I think it really add to the model to have such a strong part there, my 7939 front detached from time to time.

Overall, when I built this model I had the feeling that there were too many shortcuts but the building itself was quite straight forward ( and simple ).

Here you have my timelapse video.

Complete model

Well, this is the complete model

Train station and rail crossing

The station is almost a joke and a clear step back over the one that was available at the 7939 ( that wasn’t as nice ), I suppose that when you spend 130€ on a set you can¡t expect anything else…

The crossing it done with two ramps and has semaphores that look really nice.

Tracks

Pretty much the same that I complained with 7939, if you want to build anything remotely fun you need to spend money ( a lot of money! ) on tracks, just go and check some of my train layouts.

This set comes with 8 curved tracks and four straight tracks and really… you can’t do anything else than a small oval with them.

Locomotive

I have to say that when I saw the set for first time a few months ago, I was severely disappointed with the way it looked but once I have built it, I have to say that it looks decent enough and when moving on the tracks it looks quite well.

Both ends of the train looks exactly the same, but one of them has the IR Receiver, the battery box and the motor.

The driver cabin is extremely simple but well I suppose it is more than enough.

Passenger Car

If you compare this model with the Horizon Express the result is disappointing ( how many times I have wrote this?! ) but again, I suppose that for a simple set like this the result is decent enough.

There are no extra details inside the car beyond a few chairs and a block that works as a table.

Minifigs

This set comes with three minifigs, one train driver that was driving and had no time for a photo and the two others that you are watching here.

Overview

Miguel says 8/10

Building experience
Value for money
Playability
Parts

Pros

– It looks quite nice when moving on the tracks.
– It is quite straight forward to build

Cons

– Expensive
– As with 7939 Passenger train, I really miss more tracks.

Does LEGO 60051 worth the money?

Nah, it doesn’t matter what I say… if you are a train hardcore fan you will get it. If you are new to LEGO Trains, do yourself a favour and order a few ( no less than four ) Tracks boxes when you get this.

Always check at Amazon for a deal of the 60051 Passenger Train before anything else.

The post LEGO 60051 Passenger Train Review appeared first on The Technic Gear.

If you are interested in buying some of them you better hurry up because many of them has already been retired…. so without more delays…. here they are, the best LEGO Lord of the Rings Sets, and also some from The Hobbit.

1. LEGO 9474 The Battle of Helm’s Deep

This was my first LEGO The Lord of the Rings set. It is a expensive set but it is really HUGE, with lots of minifigs and bricks.

Here is my timelapse building

2. LEGO 10237 The Tower of Orthanc

I have this on my wishlist. The tower looks awesome and it is really tall. Also it features and Ent as well as Gandalf the White. Must have.

Here you have a video review by Jangbricks

3. LEGO 79003 An unexpected Gathering

This is Bilbo Baggins’s home and this set in particular is based on The Hobbit when all the dwarves meet in Bilbo’s house to go and claim Smaug’s treasure.

Here you have The Brick Show review

4. LEGO 9473 The Mines of Moria

When I saw this part on the movie I got really excited… building it now with LEGO is as exciting. I love the way the Troll looks.

Here you have the video review

5. LEGO 79008 Pirate Ship Ambush

Big? Check. Lots of minifigs? Check. Lots of parts? Check. Who wants anything else? Maybe a few ghost more would have been interesting but it is a very nice set.

Here is the video review

6. LEGO 79006 The Council of Elrond

This is a small set that it is the Council of Elrond that appears on the first book of The Lord of the Rings when men, dwarves and elves meet to decide what to do with the ring. They really get a fantastic result for the size.

Here is my video review

7. LEGO 79013 Lake Town Chase

This is part of the sets released for the second part of The Hobbit and I have to say that I love the way it looks.

Here is a video review

8. LEGO 79004 Barrel Escape

Released in 2013 as a preview set of The Hobbit 2nd film, it is based on the scene where the dwarves and Bilbo escape from Mirklwood using barrels of wine.

And the video review…

Is your favourite missing?

Drop me a comment and let’s discuss it!

The post The Best LEGO Lord of the Rings & The Hobbit Sets appeared first on The Technic Gear.

What happens when you move one meter straight with different wheels?

So the best way of understanding the problem was to force a big wheel difference so I just replaced with two different wheels: one of 56mm and another of 44mm of diameter. So let’s begin to see what happens with the simplest case.

Differential drive movement theory

If you need to know a bit of the Maths behind straight line movemeny, I explained them in this short video.

Different size wheels and movement using biggest wheel diameter

The simplest approach is using the biggest wheel diameter and cross your fingers.
The code is pretty much like this:

      double maxWheel=leftWheel;
      if(rightWheel>leftWheel) {
        maxWheel=rightWheel;
      }
      
      degrees=(int)((length/(maxWheel*Math.PI))*360);
      
      left.rotate(degrees,true);
      right.rotate(degrees);
      left.waitComplete();

As you can see on the video the robot steers clearly to the side with the smallest wheel, and that is because the biggest wheels is moving more distance that the smallest one.

Different size wheels and movement using average wheel diameter

We can try to compute the average diameter and move the average diameter… will it be useful?
The code is pretty much like this:

      double meanWheel=(leftWheel+rightWheel)/2.0;
      
      degrees=(int)((length/(meanWheel*Math.PI))*360);
      
      left.rotate(degrees,true);
      right.rotate(degrees);
      left.waitComplete();

Again, as you can see in the video it still moves to the side with the smallest wheel for the very same reasons that the above case.

Using different amount of rotations for each motor

The problem is that the smallest wheel runs less distance than the big wheel so we could try to make each wheel rotate a different amount of degrees with a code like this.

      degrees=(int)((length/(leftWheel*Math.PI))*360);    
      left.rotate(degrees,true);
      
      degrees=(int)((length/(rightWheel*Math.PI))*360);
      right.rotate(degrees);
      
      left.waitComplete();

Now both wheels will move one meter… but as you can see on the video it is still not enough. Why? Because despite the fact that both wheels moves the same amount of distance, they do it at different speed.

Using different speed for each wheel

Ok, if you are still here you should have realized that we need to apply different speed to each wheel… but how do we set speed?

v = d/t

So we can write

vl = dl * π/t
vr = dr * π/t

As we want them to arrive at the same time, t is the same for both expressions so we can write:

dl / vl = dr / vr

We set vl to any value we want and then we can define vr as

vr = dt * vl / dl

So, this is the code:

    int lspeed=400;
      left.setSpeed(lspeed);
    int rspeed=(int)(lspeed*leftWheel/rightWheel);
      right.setSpeed(rspeed);
  
      degrees=(int)((length/(leftWheel*Math.PI))*360);    
      left.rotate(degrees,true);
      
      degrees=(int)((length/(rightWheel*Math.PI))*360);
      right.rotate(degrees);
      
      left.waitComplete();

So you can see the result on the video and … WTF!!! It doesn’t work. Why? WHY! oh, Why!? Look again the video and see how the biggest wheel reaches its top speed sooner than the smaller resulting in a small but noticeable turn.

Using different accelerations for each wheel

So, in our last step to solve the problem we are going to calculate the new acceleration for each wheel. Again, we can define acceleration as:

a= Δv / Δt

If we consider the time from zero to top speed we get:

al = vl / t
ar = vr / t

As we want to reach the top speed at the same time we can write

vl / al = vr / ar

And as we did before… we set the left acceleration to some reasonable value and calculate right one with

ar = vr * al / vl

So we get this code…

  lspeed=400;
    left.setSpeed(lspeed);
    rspeed=(int)(lspeed*leftWheel/rightWheel);
    right.setSpeed(rspeed);

    int lacceleration=400;
    left.setAcceleration(lacceleration);
    int racceleration=(int)(lacceleration*rspeed/(double)lspeed);
    right.setAcceleration(racceleration);

    degrees=(int)((length/(leftWheel*Math.PI))*360);    
    left.rotate(degrees,true);
    
    degrees=(int)((length/(rightWheel*Math.PI))*360);
    right.rotate(degrees);
    
    left.waitComplete();

And as you can see on the video it does work! Yes!

Download source code

You can download here the code for EV3 leJOS

Just import these two files in a leJOS Eclipse and you are done. Or simply put them on the same folder and make it an Eclipse source folder.

Miguel says…

It is really cool to see the asymmetric robot moves straight and as I have been writing lately I wasn’t expecting something so simple to be so hard. Good luck implementing this using EV3 software…

The post What happens when a Robot has different size wheels? appeared first on The Technic Gear.

So, if you recall our squares drawing robot, we needed to travel around the four legs of a square turning 90 degrees on each corner so that we ended in the initial position using nothing but the encoders available at the EV3 Large motors. That’s called odometry: the usage of data from motion sensors to estimate change in position over time.

So, in order to do our task we needed to know the wheel diameter and the wheelbase. Every one knows what the wheel diameter is ( in fact you can see the measure printed on the sides of the LEGO wheels… ) but the wheelbase is a bit more complex to define: it is the distance between the effective point where the wheels touch the ground. Unfortunately our LEGO wheels don’t cover point but a wide area, so it is unknown were the wheels in fact touch the ground, and that will surely depend of many factors like robot load, floor surface, etc…

So calibration of a differential drive robot using odometry allow us to get a more precise knowledge of where our robot is when it is moving and this will be quite helpful when running more complex techniques as localization.

Sources of error in differential robots odometry

So why the hell does the robot get the path so wrong? Well, we have two kind of errors: non-systematic errors that are those errors of position as a result of wheel slippage, uneven floor, robot bouncing against an obstacle, fast turning, etc… we can’t do anything with just odometry about them.
Systematic errors on the other hand are due to unequal wheel diameters, incorrectly aligned wheels, uncertainty about the wheelbase and the limited resolution of our encoder.

By correctly calibrating our robot we can reduce systematic errors increasing the precision for robot localization and saving battery life and CPU power.

Some basic Math about differential-drive robots

Before reading about how to calibrate, I wrote two little videos ( literally! ) about the Maths behind differential robots. It is good to refresh the idea even if it is too simple.
There are two kind of movements that we want to do:

Straight movement

Rotation movement

The brute force approach

Before explaining you the UMBMark method of robot calibration, let me explain you how you can achieve the same result with a hell less of maths and perhaps a bit less of time.

What do I need?

Obviously you need your differential-drive robot at hand, a measure tape and paper.

Initial differential-drive robot configuration

To begin, we are going to use the supplied wheels diameter and we will measure how big the distance between the center of the wheels is, that is going to be our wheel base.
For my robot.

Wh. Diameter = 6.24
Wheelbase = 12.8

Brute force calibration program

We are going to reuse our square path program, so we are just going to make five 1 meter-side square and at the end of each square it will wait for us to press a key.

Much like this ( Don’t worry. You can download the source code at the end of the article ).

    System.out.println("CW Run");
    brick.getAudio().systemSound(1);
    Button.waitForAnyPress();
    
    for(int j=0;j<5;j++) {
      for(int i=0;i<4;i++) {
        /* Move straight the squareSize centimetres */
        int degrees=(int)Math.round((squareSize/
          wheelCircunference)*360.0);
        left.rotate(degrees,true);
        right.rotate(degrees);
        left.waitComplete();
        
        /* Rotate on the spot */
        degrees=(int)Math.round((((wheelBase*Math.PI)/
          4.0)/wheelCircunference)*360.0);
  
        left.rotate(-degrees,true);
        right.rotate(degrees);
        left.waitComplete();  
      }
      
      System.out.println("CW: "+(j+1)+"/5");
      brick.getAudio().systemSound(0);
      Button.waitForAnyPress();
    }

Get the calibration data

So we mark a point on the ground with a bit of black tape, and measure the distance to a L shaped wall next to it ( the closer the better, but allow at least 40-50cm ). Now, place the robot with extreme care over that point ( and from now on, on the very same position and orientation ).

Press any key and let the robot do one square. Now measure the distance from the ending point to the L shape wall and write it down. My advice is to give a name ( X and Y for example to each of the walls so you use the same everytime ).

Ok, make the other four patrols and write down all the results.

So now we need to know how big is the error, so we subtract the initial position from the finish position and that will give us a nice idea of the error. The bigger, the worse.

Xerror= Xfinish_pos - Xinitial
Yerror= Yfinish_pos - Yinitial

So unless you are incredible lucky you will end with one of these two situations.

Over-steering in differential-drive robot

The robot turned more that 90ª on each of the turns so it ended steering more than it was supposed to do.

Under-steering in differential-drive robot

In this other case the robot turned less than 90 degrees on each corner.

Estimate new wheelbase

In both cases the path is wrong because of two reasons: differences on wheel diameter and error on wheelbase. The first is quite small for LEGO parts, around a 0.01% on the experiments I have done, so my advise is to just dismiss it (for simplicity) and fix wheelbase.

If you recall the Maths about how much to turn we get that

wheelbase / wheeldiameter rotations for a complete 360º turn.

So how do we write a new wheelbase for the robot? It is quite simple . If you robot over-steers on the square path, decrease the wheelbase and if it under-steered increase it. How much? The worse the bigger the change needed. I won’t go beyond 5% of the wheel base changes on a single step.

Iterate

This fine-tuning of our differential-drive robot is an iterative process so configure the new wheelbase and run it again and again until you are satisfied with the result. In the end the robot should on average land over the initial point, the existing errors, mainly due to non-systematic errors, are something you are going to need to live with until we add sensors to our robot.

The UMBMark calibration process

Perhaps you arrived here from Google looking about how to do this. On this paper, Borenstein and Feng proposes a systematic method for calibration of differential-drive robots. You can read the original paper here.

What do I need?

As with the brute-force approach you will need the differential robot and measuring tape… or three sonar sensors with a 2mm precision. [ Yep, I preferred too the measuring tape ]

Initial differential-drive robot configuration

To begin, we are going to use the supplied wheels diameter and we will measure how big the distance between the center of the wheels is, that is going to be our wheel base.
For my robot.

Wh. Diameter = 6.24
Wheelbase = 12.8

This is going to be our nominal measures… but before explaining how to do it, let me explain the Maths behind the idea on the paper, it is pretty interesting, it is simple enough and you will have a clear idea of why it isn’t optimal.

UMBMark Calibration program

We are going to reuse our brute-force program, so we are just going to make five 1 meter-side square and at the end of each square it will wait for us to press a key. When the five squares are done we will make another five squares in the counter-clockwise direction.

So the resulting program is pretty much like this.

    /* Initialize motors */
    left.setAcceleration(400);
    right.setAcceleration(400);

    left.setSpeed(speed);
    right.setSpeed((int)((cr/cl)*speed));
    
    System.out.println("CW Run");
    brick.getAudio().systemSound(1);
    Button.waitForAnyPress();
    
    int degrees=0;
    
    for(int j=0;j<1;j++) {
      for(int i=0;i<4;i++) {
        /* Move straight the squareSize centimeters */
        degrees=(int)Math.round((squareSize/
          (wheelDiameter*cl*Math.PI))*360.0);
        left.rotate(degrees,true);
        degrees=(int)Math.round((squareSize/
          (wheelDiameter*cr*Math.PI))*360.0);
        right.rotate(degrees);
        left.waitComplete();
        
        /* Rotate on the spot */
        degrees=(int)Math.round(wheelBase/
          (4.0*wheelDiameter*cl)*360.0);
        left.rotate(-degrees,true);
        degrees=(int)Math.round(wheelBase/
          (4.0*wheelDiameter*cr)*360.0);
        right.rotate(degrees);
        left.waitComplete();  
      }
      
      System.out.println("CW: "+(j+1)+"/5");
      brick.getAudio().systemSound(0);
      Button.waitForAnyPress();
    }
        
    System.out.println("CCW Run");
    brick.getAudio().systemSound(4);
    Button.waitForAnyPress();
    
    for(int j=0;j<1;j++) {
      for(int i=0;i<4;i++) {
        /* Move straight the squareSize centimeters */
        degrees=(int)Math.round((squareSize/
          (wheelDiameter*cl*Math.PI))*360.0);
        left.rotate(degrees,true);
        degrees=(int)Math.round((squareSize/
          (wheelDiameter*cr*Math.PI))*360.0);
        right.rotate(degrees);
        left.waitComplete();
        
        /* Rotate on the spot */
        degrees=(int)Math.round(wheelBase/
          (4.0*wheelDiameter*cl)*360.0);
        left.rotate(degrees,true);
        degrees=(int)Math.round(wheelBase/
          (4.0*wheelDiameter*cr)*360.0);
        right.rotate(-degrees);
        left.waitComplete();  
      }
      
      System.out.println("CCW: "+(j+1)+"/5");
      brick.getAudio().systemSound(0);
      Button.waitForAnyPress();
    }    
  }

Get the calibration data for UMBMark

So as we did with brute-force approach, we mark a point on the ground with a bit of black tape, and measure the distance to a L shaped wall next to it ( the closer the better, but allow at least 40-50cm ). Now, place the robot with extreme care over that point ( and from now on, on the very same position and orientation ).

Press any key and let the robot do one square. Now measure the distance from the ending point to the L shape wall and write it down. My advice is to give a name ( X and Y for example to each of the walls so you use the same everytime ).

Ok, make the other four patrols and write down all the results.

Now, place the robot on the oposite direction and run the counter-clockwise part of the test. Write as before the results. ( Make sure the robot doesn’t collide with any wall or your will ruin the data ).

So now we need to know how big is the error, so we subtract the initial position from the finish position and that will give us a nice idea of the error. The bigger, the worse.

Ok, now you have the measure you should have something pretty close to this. ( You can use LibreOffice Calc to draw it ).

Ok, now we calculate the center of both sets of points CW and CCW ( It is the mean value of both x and y ).

Xcgcw = 32.5
Ycgcw = -19.94

Xcgccw = 30.36
Ycgccw = -16.2


Now we calculate β and α as explained above. For my example the results are:

αx = -0.15715
αy = 0.00935

βx = -0.00535
βy = 0.09035

Both results are in radians. On the original paper they say that you can calculate α using either X or Y values… and there is implicit there that the value is the same ( f@$% you! I lost a full day on this stupid thing. ). But it isn’t, so don’t despair, either use one of them or use the average. I used αx and βx.

So once we have β and α we can calculate the Effective Wheelbase ( Eb ) and the Effective wheel diameter (Ed). Much like this

Eb = 0.9090538881

Ed = 0.9993154352

So this means that most of the error comes from the Effective wheelbase ( what a surprise! ) and that the wheels are quite similar with the one 0.9993 smaller than the other.

Fixing your robot with Eb and Ed results

All the changes you need are done on software. We are going to fix first the most simple one, Eb.

In order to correct wheelbase we recall that we defined Eb as

Eb= Bactual/Bnominal

So we just need to alter the wheelbase as this:

wheelbase=wheelbase * Eb

Now we may want to correct the Ed. From the results I have gotten is several runs of the tests the difference between one wheel and the other is below 0.1%. You should (really) ask yourself if it is worth the time. I really think it isn’t mainly because EV3 doesn’t work with enough precision to make the change noticeable… unless you plan to run your robot on a wide open room.

Once we know Ed we can calculate a correction factor Cr and Cl for each wheel. So we correct the amount of degrees each wheel turns by multiplying the amount by Cl and Cr. Done? Well no, in fact if you fix Ed like that one wheel will stop moving sooner than the other so we need to change the speed of each wheel so both finish at the same moment.

So the amount of time each wheel is going to take to move is

degrees · Cl · vl
degrees · Cr · vr

Where vl and vr are the speed each wheel moves.

As we want both amounts to be the same…

degrees · Cl · vl = degrees · Cr · vr

vr = (Cl/Cr) * vl

Edit it and you are almost done. Now we need to change the acceleration of each motor so they both reach the maximum speed at the same time so we get a straight line.

So as we define acceleration as

a= δv/δt

We can write

t=Vr/ar
t=Vl/al

As we want that top speed is achieved at the same time for both motors…

Vl/al=Vr/ar

So we can set

al=200
ar=(vr*al)/vl

So we change the acceleration on the code and voila.

UMBMark Calibration program

Just measure your robot positions and fill the data, this Excel sheet will return you the correct Eb and Ed for your robot.
Fill only the area in grey.

Bidirectional Square Path program

You can download both the leJOS version

and the EV3 version

And this is the EV3 file.

Miguel says…

Well, you have seen both methods… and I still really prefer brute force approach.
I have run around four times the UMBMark method and every time I run it, it doesn’t beat my brute-force approach.
I decided to give it a last try with my calibrated robot so I got these results when I ran the bidirectional square path on my calibrated robot.

And these are the points

As you can see the clockwise movement is very nicely calibrated but the counter-clockwise is surprisingly wrong. I suppose this is the different wheel diameter error appearance. I re-tuned it with the params that were result of running UMBMark on the above data and the result was worse than above. It made the clockwise movement as bad as the counterclockwise movement. Not sure it is what I want…

Still… I prefer the brute force approach. But I agree it is quite hard to guess the difference between each wheel with my brute-force approach.

The post HOWTO Calibrate a differential robot: UMBMark Explained appeared first on The Technic Gear.

When I bought it I found the mountain bricks are in fact a few big parts… but anyway… let’s review it.

Model data

Name Gold Mine
Ref. Code 4204
Theme City
Year 2012
Parts 748
Price £69.99
Minifigs 4
Where can I buy LEGO 4204?
Amazon

Model background

The Mine is a busy place, full of miners digging for gold!

Break up the rock with the big drilling machine and transport it out of the mine with the train. Then load it onto the conveyer belt with the crane and haul it away with the truck! There’s even a safe to keep the gold inside. Help the miners find even more gold by blasting with the dynamite! Includes 4 minifigures: crew chief, crane driver, driller and truck driver.

• Includes 4 minifigures: crew chief, crane driver, driller and truck driver
• Features mine, drill, truck and crane
• Accessories includes 3 dynamite packs, (1 with a timer), 2 detonators, 2 rocks each containing 6 gold nuggets, 36 small rocks in a selection of colors, 2 gold bars, explosion warning sign, storage box, jackhammer, fence with hazard lights, wheelbarrow, broom, shovel, pickaxe, walkie-talkie and coffee cup
• Mine features train, train track, mine door, safe and working conveyer belt
• Drill features spinning function
• Crane features rotating cabin, moving arm and lowering shovel
• Truck features articulated cab
• Drill for gold nuggets!
• Haul the rocks with the train!
• Operate the conveyer with the crane!
• Load the truck!
• Lock the gold in the safe!

Model Box

This set comes in a big box like it is the norm on expensive LEGO sets. This sets comes with seven plastic bags with all the parts.

And this is the back part of the box.

Manuals

This set comes with four manuals.

Building experience

This is a fun set to build. I have been a bit disappointed with the mountain bricks as I was expecting real bricks and not that cheap alternative. The truck head is quite nice and the mine train looks great for its size.

I just really don’t understand why LEGO decided to use such strange parts for the crane, the truck loading part and the mountain…
Here is the timelapse building and video review.

Complete model

This is the complete model.

Let’s review each part.

The Mine

The mine has several interesting parts.

It has a superb office/safe box were the gold is stored next to the train tracks.

Just over it there is a crane that it is use to load the bucket with gold and rocks from the train and a bit to the right you have a transport track that takes rocks from the bucket to the truck.

The crane

The crane is nicely done with very little but highly specific parts: LEGO this is quite close to cheating!. It can rotate over its axis and lower or raise a claws that takes rocks.

The drill machine

It looks good but really I feel like cheating… that big part on the front doesn’t look like LEGO…

The train

I really love the way the train looks. It is a narrow track train with only 4 studs width but that looks really nice and close to the original.

The truck

I have mixed feelings with this truck. It really looks quite good but the way the back part is done… so few parts… it feel pretty much like a Playmobil. Still… it is a good looking LEGO truck.

Overview

Miguel says 8/10

Building experience
Value for money
Playability
Parts

Pros

– It is big
– It is highly playable
– The built set looks really nice.

Cons

– It is expensive
– The mountain is built with just a few huge pieces

Does LEGO 4204 worth the money?

Dunno. I have mixed feelings. The full set looks nice and it is big but on the other hand there aren’t so many parts on a set so expensive. Decide yourself, if you have an extra pocket money, this set does a nice acquisition but it won’t be my first option for LEGO City.

The post LEGO 4204 Gold Mine Review appeared first on The Technic Gear.

Most of the documentation available for leJOS is oriented to Mindstorms NXT and unfortunately the EV3 uses a new API that is going to be the standard in 1.0.0. What that means for you? Well, that unfortunately there are very little options to learn on your own and the samples provided for leJOS EV3 are so complex and with so many hard to follow concepts that you will have a hard time learning from them… so… here I am to the rescue!

Understanding the basic leJOS program

Let’s get back to our Hello World example.

So to create your first leJOS program you need to create a new leJOS project and then create a new Class and make sure it has a main method. Our code is so simple we can directly write the code on the main method, no need for other methods or classes.

So first thing we do is use a helper class called BrickFinder that try to determine if we are running on a EV3 and if not it tries to contact a remote EV3. On case of success it will return an EV3Brick object or an exception if it fails to find an EV3 brick.

So once we have the brick we can access some of it features: buttons, sensor ports or LCD. You could just directly print using System.out.println at this point but it isn’t as exciting… isn’t it?

So once we have the brick, let’s get access to its LCD object and let’s draw a string on the screen.

Got it? Well, let’s do something more interesting. I am going to show you two ways of doing things… one manipulating motors and sensors directly and another way using classes available at leJOS to make your life easier. Personally I think it is a bad ( BAD! ) idea to use the latter directly without really understanding what it is going on. The good thing is that source code is available and you can study them.

Using EV3 Motors with leJOS

The EV3 Set comes with two kind of motors two large motors and one medium motor with more speed but less torque. There are two different class to handle them.

The Large motor is quite powerful and has a 160rpm speed

The Medium motor is smaller and easier to attach to your robot and although it has less torque it is faster.

Also you need to understand that EV3 motors are Regulated. It is not easy to notice this on the EV3 software because all the blocks give no indication about it… but on the advanced blocks there is a unregulated motor block. So what the hell means regulated? You may be aware that your motors have a built-in rotation sensors that can track changes of their position with a precision of up to 1 degree. Well, using these rotation sensors and a PID controller ( pretty much like the line following one ) LEGO coded the blocks to that when you say to a motor to move at 60% of power the motor will move to that power level but if for any reasons it is slowed down ( an obstacle, different kind of floor, more weight ) the block will increase the power given to the robot to make it move to the desired power using a PID controller. The very same thing happens when you ask it to rotate 75 degrees.

So the EV3LargeRegulatedMotor is pretty much the same that the EV3 Large Motor Block. You can check the methods on the EV3 leJOS API but I will show you the most useful.

Interesting EV3 Large Regulated Motor methods

First is the constructor, we need to pass the port to which the motor is attached. So using the method brick.getPort(“A”) we get access to the A port. This is the new way of accessing ports.

EV3LargeRegulatedMotor motor = new EV3LargeRegulatedMotor(brick.getPort("A"));


forward and backward

This class has two methods to make the motor move forward ( or backward ). The speed and acceleration is determine with other methods. So once you call any of these methods the motor will start moving.


motor.foward()


flt and stop

So eventually I am sure you will want to stop the motor and we have two options.

The flt method will stop the current to the motor and will left it floating.

motor.flt()


The stop method on the other hand will actually brake and stop the motor.

motor.stop()


Both methods have an optional boolean parameter immediateReturn. If it is true the method will issue the order and return to its caller ( that it is usually the behaviour you want, specially when you are operation two motors in parallel ), if you skip the parameter or set it to false the method won’t return until the motor is actually stopped and that can take a few hundred of milliseconds.


motor.stop(true)
// do something else unrelated to THIS motor
motor.waitComplete();


rotate

The above methods are perfect but on most situations you want to measure how many degrees your motor moves, and this is the perfect method. It will turn your motor with a precision of +/-1 degrees. And negative degrees works :)


motor.rotate(10)


As with the previous methods, this one accepts an extra boolean parameter to return as soon as the order is issued or wait for the task to complete.

setSpeed and setAcceleration

These methods set the speed in degrees per second and the acceleration. They are really cool because let you implement the ramp up and ramp down operation of motors so you can reduce slippage to the minimum.

Creating a robot that does a patrolling squared route

Please don’t skip this step. Even if you think it is stupid and too simple, give it a try. You will be as surprised as I was when I realized how hard ( impossible? ) to get this right.
The first step is to build a little robot to accomplish the task, so my advice is to build a differential drive robot much like this.

If you have problems building it, use Simplebot instructions. We are not going to use any sensor in this step.
So, now that we have a robot we are going to make it move over a 50cm square so that it ends on the same position that it started.

Do you want to do on your own? I am here waiting…

Ok, are you back? Did it work? ( drop me a comment and better a photo! )

Now get a measuring tape and measure the diameter of your wheels (B), the width of the wheel (C) and the distance between the wheels (A)… much like in this image.
We will use this data to calibrate our robot.

I am going to use two different ways of doing this in leJOS, one is low level, much like EV3 and the other is the simpler way leJOS offers. But before this, let’s see the two types of movements that we need to do in this robot: moving forward and steering.

Moving 50 centimeters forward with a differential robot

This is the easy part of the movement. My robot has a wheels of 6.24 cm diameter so to know how much we need to turn then to move forward we do a simple

Each complete rotation of the wheel means:

distance moved = 3.1415 * diameter


So if we want to move 50 centimetres we need to turn our wheels…

amount of turns = 50 cm / distance moved


And instead of using rotations I prefer to pass degrees to the block so…

degrees = amount of turn * 360


So for my robot this would be

3.1415 * 6.24 = 19.60 cm

50 / 19.60 = 2.55 rotations * 360 degrees = 918 degrees


You can safely ignore the final degrees because EV3 rotation sensors has a precision of +/-1 degree.
If we do this with leJOS it would be like…

/* Move straight the squareSize centimetres */
int degrees=(int)Math.round((squareSize/wheelCircunference)*360.0);
left.rotate(degrees,true);
right.rotate(degrees);


Or using the DifferentialPilot class…

pilot.travel(50);


Rotate 90 degrees on a diferential robot

Ok, we just now need to rotate our robot 90 degrees on each turn to make a square. This is slightly more complex that moving forward but don’t get scared, it is still very simple maths.

As our robot can rotate over a point ( just make each wheel rotate on different directions at the same speed and you will see it ), it will create a cicle of radius around half the track of the robot, the distance between center of the wheels.

distance = track * 3.1415


So distance is how much would the robot has turned when rotation a full rotation but we want to rotate only 90 degrees so…

90 degrees distance = distance / 4


And using the amount of distance run for each rotation from the previous task…

rotations = 90 degrees distance / distance run by wheels


And again we translated this in degrees

90 degrees turn = rotations * 360


Let see the numbers with my robot…

3.1415 * 11.9 = 37.38 / 4 = 9.34
9.34/ 19.60 = 0.476
0.476 * 360 = 171 degrees


You can safely ignore the final degrees because EV3 rotation sensors has a precision of +/-1 degree.
If we do this with leJOS it would be like…

/* Rotate on the spot */
degrees=(int)Math.round((((robotTrack*Math.PI)/4.0)/wheelCircunference)*360.0);

left.rotate(-degrees,true);
right.rotate(degrees);


Or using the DifferentialPilot class…

pilot.rotate(90);


Try it yourself

With the above information you can try it already yourself. But if you prefer you many have a look at the finished programs.
This is the low level motor access program

/**
 * This program runs on a differential robot that has 62.4mm diameter wheels and a robot track of 122mm.
 * This robot has a pen on the center of rotation and it will draw a square of 40cm. 
 * 
 * @author miguel
 *
 */
public class DrawSquare {
  static double wheelDiameter=6.24;
  static double robotTrack=12.2;
  
  public static void main(String[] args) {
    // Distances and sizes are expressed in centrimetres.
    int squareSize=40;
    double wheelCircunference=DrawSquare.wheelDiameter*Math.PI;
    
    Brick brick=BrickFinder.getDefault();
    
    RegulatedMotor left=new EV3LargeRegulatedMotor(brick.getPort("B"));
    RegulatedMotor right=new EV3LargeRegulatedMotor(brick.getPort("C"));
    
    /* Initialize motors */
    left.setAcceleration(400);
    right.setAcceleration(400);

    left.setSpeed(400);
    right.setSpeed(400);
    
    for(int i=0;i<4;i++) {
      /* Move straight the squareSize centimetres */
      int degrees=(int)Math.round((squareSize/wheelCircunference)*360.0);
      left.rotate(degrees,true);
      right.rotate(degrees);
      
      /* Rotate on the spot */
      degrees=(int)Math.round((((robotTrack*Math.PI)/4.0)/wheelCircunference)*360.0);

      // K is a calibration parametrer to turn the robot.
      double K=0.98;
      degrees=(int)(K*degrees);
      
      left.rotate(-degrees,true);
      right.rotate(degrees);
    }
    
  }

}

And this one is using the DifferentialPilot class

/**
 * This program runs on a differential robot that has 62.4mm diameter wheels and a robot track of 115.5mm.
 * This robot has a pen on the center of rotation and it will draw a square of 40cm. 
 * 
 * It is done using the DifferentialPilot class.
 * 
 * @author miguel
 *
 */
public class DrawSquarePilot {

	public static void main(String[] args) {
		Brick brick=BrickFinder.getDefault();
		
		RegulatedMotor leftMotor=new EV3LargeRegulatedMotor(brick.getPort("B"));
		RegulatedMotor rightMotor=new EV3LargeRegulatedMotor(brick.getPort("C"));
		
		DifferentialPilot pilot=new DifferentialPilot(6.24, 11.55, leftMotor, rightMotor);
		
		for(int i=0;i<4;i++) {
			pilot.travel(40);
			pilot.rotate(90);
		}

	}

}

Integrating and calibration of the differential robot

Ok, are you done? Now comes the fun part. Run your robot.

Surprise! Did it work? I would be quite surprise if it did. So we need to calibrate it so that it work correctly. You will surely have a small error on the forward movement but a big error on the rotation movement. Yes? Why?
The forward movement error can be caused by things like wheels slippage, different terrain , different level and the rotation sensor error but overall it should be quite small, maybe around 1%.

But the rotation movement is almost sure quite wrong. You don’t need any tool to see that the robot is steering a way more ( or less ) than 90 degrees. Why? Because your wheels are wide and you don’t really need where they touch the ground, so we need to calibrate this parameter to get it right. How? Just multiply the amount of degrees by a constant value K… and to guess the value of K you run your robot with different values until you get it right, start with 0.98, does it gets better? So keep going…

Once you get it almost right you should have something like this.

Ok, you are almost done. Keep calibrating the K param until you get almost a perfect square most of the times. It is the best you can do without any sensor.

Source code for leJOS EV3

Don’t want to write your own code? Download from here the EV3 source code and the leJOS code for both the lowlevel motor manipulation and the DifferentialPilot class.

Here is the EV3 code

And this is the low-level leJOS code manipulating the motors directly and the same program done using a differential drive.

Remember all the source code on The Technic Gear is release as open source GNU GPL 3.0

Take the challenge

If you complete the robot and write or run the programs and calibrate to the best you can… you will realize that there is still an error. So without using any sensor, how can we improve even more the result? Think about it and drop a comment. I will score ideas from 0 to 10.

Miguel says…

Hope you have enjoyed this introduction to leJOS. In the next article we will introduce sensor handling using leJOS. If you have any question, drop me a comment and I will try to help you.

Please, if you enjoyed this article share it with your friends.

The post Draw a Square: Using Motors in leJOS EV3 appeared first on The Technic Gear.

I have created two different layouts to work with slopes. First, the longest LEGO Train track with several switch tracks that I have built so far.

And then this past weekend I have built a two levels loop using ramp up and down to the sides and Horizon Express.

Now I am just waiting for the new LEGO Trains ( and Train Station )that are going to be release this summer so that I can get more tracks and more trains to make it even bigger and better! :)

The post Playing with LEGO Train Tracks: Slopes, x-crosses and levels appeared first on The Technic Gear.

Here is the review

Model data

Name Superman Metropolis Showdown
Ref. Code 76002
Theme Super heroes
Year 2013
Parts 119
Price £11.99
Minifigs 2
Where can I buy LEGO 76002?
Amazon

Model background

Stop General Zod with Superman!

General Zod is wreaking havoc in a downtown Metropolis Showdown against Superman. Stop General Zod from trapping Superman under the collapsing antenna tower by blocking it with the cool yellow car. Battle as you take Superman up the tower, flip him through the air with the catapult function and swing him on the antenna. Includes 2 minifigures: Superman and General Zod.

Model Box

It is a small box for such nice set… this is the front.

And this is the back of the box.

Manuals

Two manuals.

Building experience

It is a small model to build but the car is quite a experience in itself. It isn’t complex to build but it looks quite well done once build… not like other cheap LEGO cars… yes, I am talking about you LEGO Train Station Taxi!

Here is the timelapse building and videoreview

Complete model

Car

The car is really good looking although it has only room for the pilot.

Minifigs

This set comes with two minifigs: Superman and General Zod

Overview

Miguel says 6/10

Building experience
Value for money
Playability
Parts

Pros

– Nice and the car looks fantastic.

Cons

– Maybe a bit small and simple.

Does LEGO 76002 worth the money?

I have mixed feelings. Get it if you are a fan of Superman or if you love the car.

The post LEGO DC Superheroes 76002 Superman Metropolis Showdown appeared first on The Technic Gear.