LEGO Digital Crawler with EV3 Controlled Gear Box

This LEGO remote controlled crawler uses a sequential gearbox from Sariel and a Mindstorms EV3 to control the car. The remote control used force feedback and offers proportional control over speed and direction. It also allows you to change gears and change the forward and backward drive. The two EV3 Mindstorms communicate using Bluetooth. The remote uses two rotation sensors to measure speed and direction.

The building instructions are available for LEGO Digital Designer and Please notice that I had to replace the 35188 Technic Changeover Rotary Catch with another gear in the digital model and I could also not include Mindsensors Glide Wheel Rotation Sensor. These bricks do not yet exist in digital form. I also put up the model are ReBrickable and the inventory there is almost complete. Feel free to also use different wheels. In the LDD model I also had to use other shocks.

Here is a video that explains the model’s function:

And here is the crawler in action:



Simple LEGO Mindstorms Mars Rover

This is simple Mars Rover model using two LEGO Mindstorms EV3 and a total of eight motors. The two EV3 are daisy chained and the model can be controlled using the EV3 IR Remote Control. The model uses the rocker-bogie suspension system including a differential in the middle axis. The two EV3s are suspended and remain horizontal in any position. There are much more complex Mars Rover models already available using many more Mindstorm bricks. My design goal was to keep it simple and experiment with the rocker-bogie suspension system. The principles works, but there is a bit too much flexibility in the model.

The 3D model and the building instructions are available for LEGO Digital Designer. The parts list and instructions are also available at Rebrickable.


TicTacToe Playing LEGO Mindstorms Robot Using Computer Vision

You can play TicTacToe with this LEGO Mindstorms EV3 robot. It uses three motors to drop the balls into the right field. It uses a NXTCam to view the board and then calculates the best move using a MiniMax Algorithm. All future moves are explored an rated according to their winning chances. The work is based on the TicTacToe code of Thomas Kaffka. An IR sensor detects your hand when you drop your ball. The robot is using red balls and the human player uses blue balls. The Java code is available over at Github. The building instructions are available for LEGO Digital Designer. I used the MinuteBot baseplate, which is useful for building static Technic/Mindstorms models.


LDD does not have all the required pars in its database. You will have to replace 22961 with 27940. You will also need to add a worm wheel 27938. In addition you should use a lamp to provide consistent lighting. I used a USB powered LED circular lamp the can be powered through the USB port of the EV3. I only had to take out the lens in the middle so that the camera fits through the hole. A rubber band holds the light in place. To calibrate the robot I added a little arm at the end of the base plate against which the robot arm rotates. The position of the camera can be centered on the board using the wrench and through sliding along the axles.

You can also find information about the robot over at Rebrickable. The inventory there is correct and complete. Except for the base plate of course.


Tutorial on connecting LEGO Mindstorms EV3 to WiFi

This video shows how to connect your LEGO Mindstorms EV3 to your WiFi network so that you can program it away from your computer. I use the Netgear N150 Wireless Adapter (WNA1100), which is the only officially supported WiFi dongle for the EV3. The N150 is difficult to get these days, since Netgear has moved on producing newer sticks. So buy them now before they disappear completely. On the plus side, they are also very cheap right now on eBay and other market places. I got my for only 19 NZD from TradeMe.

It would be great if LEGO would support more dongles, in particular smaller ones. Furthermore, it would be great if it would be possible to use WPS. Entering your WiFi password on the EV3 is tedious. It would even be better if the EV3 would remember the WiFi password. You need to enter it every time you switch the EV3 on.