I have several motors, and a microcontroller. The microcontroller sends 3.5v signals to the motors, which are powered by a separate 5v source. (The microcontroller also runs off the 5v.) Problem is, it seems like the power supply is insufficient. When the motors start up, or when they're all trying to move, they often behave strangely, and the microcontroller sometimes resets. If I increase the voltage, they behave better - but I have to increase it to like 6v, and I'm worried about pushing it much farther, since the microcontroller and motors are only supposed to get 5v. Looks like the motors draw up to half an amp, collectively - which is a fair amount for small motors, but not THAT much. With a multimeter, I've seen the voltage drop by over a volt. I've tried two variable power supplies and a set of 4 AA batteries, and they each show significant voltage drop. (One of the supplies was supposed to provide up to 3A. Note that both supplies seem fairly inaccurate in the voltage they claim to be producing vs the voltage they're actually producing.)
How do I get the voltage to STAY at 5v? (Or at least within 50mv of, say, 5.5v?) Is there a particular style of power supply I need, or a special intermediate box, or do I just need a massive stack of batteries in parallel? I wasn't measuring voltage AT the battery tips, merely at a convenient spot a little further downstream; only wires/connectors in the way - maybe the wires were adding some resistance??
Here's a video demonstrating the setup, and the problems. Demonstration video