sumo lego mindstorm ev3 robot design with building instructions 20x20 

how can I get the pieces?

I didn't add it due to the weight You can use it, put it in the middle at the front side or attach it with the arm

@House_of_robots Great idea You can also change the position of the ultrasound sensors, one in the front and the other in the back, to protect against any robot coming from behind.

If your ultrasonic sensor range is good so you can find the other robot easily and no need for a color sensor . In programming: in case the two ultrasonic sensors didn't find another robot so your robot will rotate around itself in its axis so can scan the ground for the another robot. If you want to use color sensor so you can put it under the ultrasonic sensors and use 2 color sensors

Thank u🥰