This chapter ends with the concept for another robot, this time one that responds to light with photoresistors. I decided not to go all the way with that, because I just spent a whole lot of time on the last cart (much of it on fabrication), and because I plan to follow Charles' upgrade of Experiment 32 as published in Make Magazine (March 2015).
Actually, I had a little trouble with this. First, Charles said to use 12V motors, and I could only find 5V. I found a set of that came with UL2003A driver boards on Amazon. I did not get the results I expected on the breadboard just using LEDs...I expected to see the cycle of pulses repeat, but it only did one cycle at a time. I checked the connections many times, with no success. This particular breadboard has been flaky in the past, but I'm, not willing to rewire the whole thing.
I drove the stepper using an Arduino Uno and some code I found in a tutorial on Instructables.
I made a video.
On to the Picaxe in Experiment 34!