I have built a bumper car with Lego Dacta. I also used the Lego RCX brick. The Lego RCX brick is the main part of the bumper car. The RCX brick is a small computer which allows the bumper car to go farther than the control lab kit because the RCX brick doesn't need any wires to go far. The RCX brick has 5 programs. I used program 1 for my project. I did a lot of downloading to the RCX to tell it what to do. I had to keep experimenting with the procedures to get it to work right. Each time I made a change I had to download the program to the RCX brick using the infrared tower connected to the desktop computer. The bumper car has touch sensors behind the bumpers so that when it bumps into something, the touch sensor button is switched on. The bumper car then backs up, turns left, and goes forward again. Below is a picture of the bumper car and procedures.
to start
forward
asetpower 4
csetpower 4
loop[drive]
end
to back
athisway
cthisway
aon
con
wait 5
aoff
coff
end
to forward
athatway
cthatway
aon
con
end
to left
athisway
cthatway
aon
con
wait 3
aoff
coff
end
to drive
ifelse switch1 [aoff coff back left forward] [aon con]
ifelse switch3 [aoff coff back left forward] [aon con]
end