Using your own microcontroller to run a Mindstorms robot has never been easier. This project shows you how to build and run a basic Lego Mindstorms EV3 robot using an Arduino Uno R3 and a Bricktronics Shield from Wayne and Layne. The bricks used to build the robot all come from the Lego Mindstorms EV3 Home Edition and you can get the rest of the parts from the Maker Shed and Wayne and Layne’s store. It’s a fun, easy, and educational way to level up your Lego skills!

You can also substitute an old-school NXT set if you desire, or use individual parts. This is what you’ll need:

2x data wires
2x tank treads
4x rims
2x motors
2x 15M beams
2x 7M beams
2x 3M beams
1x 2M beam with cross hole
2x 7M cross axles
2x 6M cross axles
2x 3M cross blocks
3x 3M beams with snaps
2 5×7 beam frames
2 5×11 beam frames
6x bushings
4x half bushings
21x connector pegs
15x cross connector pegs
2x 3M pegs
2x 3M beams

Project Steps

Add Pegs to Motors

Lets’ begin by adding pegs to two motors. Add two cross-pegs to motors as shown in figure 1 and four normal pegs and two more cross pegs, as shown in figure 2.

Connect Motors

Use two 5×7 beam frames to connect the two motors. You can see how to do it in figure 3. Add six more pins to the back of the combined chassis, shown in figure 4.

Construct Rear Assembly

Take a 5×11 beam frame and put two pegs in it as shown in figure 5. Next, connect a 7M beam and 3M beam with snaps like you see in figure 6. Finally, add another 7M beam and two more pegs as you see in Figure 7.

Continue Rear Assembly

This sub-assembly is so nuts, let’s keep going! Add another 5×11 beam frame to the top (figure 8) and then connect the whole shebang to the back of the motors (figure 9).

Work on the Underside

Add 3M beams with snaps as shown in figure 10, then pop in five cross-pegs and one normal peg just like in figure 11. Finally, connect two 3M beams and the 2M beam with cross-hole, as shown in figure 12.

Add Rear Axles

Add cross blocks as shown in figure 13. Next, slide two 6M cross axles through the central hole of the cross blocks. Position them just like you see in figure 14. Finally, secure the axles with bushings as shown in figure 15.

Add Side Beams and Axles

Add four connector pegs and two cross pegs as shown in figure 16, then attach two 15M beams along the sides. As you can see in figure 17, the final holes of the beam will accommodate the front axles. Finally, let’s add those 7M cross axles, position them just like you see in figure 18.

Add Rims

First, let’s secure the 7M axles with bushings, as shown in figure 19. Next, add rims to all four axle-ends… I only show two in figure 20. Then secure the axles with half-bushings, seen in figure 21.

Add the Battery Pack Support

Lets finish ‘er up! Add two 3M pegs to the top of the robot as seen in figure 22. Then, connect two 7M beams just like you see in figure 23. The penultimate step in the Lego build (figure 24) is to add cross pegs to the top so you can attach your electronics. The final step (not shown) is to attach the tank treads to the rims. You may need to gently stretch out the treads to make them fit.

Build Electronics Package

Begin with the battery pack plate. Attach the pack to the plate, and screw in the standoffs from below using the M4 screws. (Note I ended up using #4-40 x 1/4″ screws and nuts to attach the pack to the board.)

Connect the Arduino to its mounting plate using #4-40 x 0.75″ screws. Attach the plate to the standoffs using more M4 screws. Attach the Bricktronics Shield to the Arduino.

Connect the Wires

The Mindstorms wires connect from the motor terminals to the motor ports on the shield.

Program the Arduino

Use the “drawbot” example sketch from the Bricktronics library as a starting point for your tank. It’s not perfect for this robot but it will get you started!