I have a bot that is almost
I have a bot that is almost exactly like this, that I built to play around with code on before intergrating ‘intelligence’ into my large mobile platform. One thing I noticed, is when running the arduino off a 9v battery, and the motors off 4 AA batteries… my ultrasonic sensor was not working exact, I removed the 4 AA batteries and the 9v battery and now power the entire thing from a 11v 3cell R/C battery and it functions perfectly. Plus the battery weighs less and holds more of a charge.
I’d love to see your code, just to see how it compares to mine.