My 2nd and 3rd robots, the first one was disassembled(Sumo Robot), I used some parts of it to build the obstacle avoiding robot. The chassis is made of aluminum, The left robot is just a black line follower robot and the right robot is an obstacle avoiding robot, the LED light on while moving, create sounds when there is an obstacle in front and the sensor moves left and right to calculate the distance where the robot will go. LMR is really a good place if you want to build robot and find some references.
This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/line-follower-robot-obstacle-avoider-robot