Hi there, I have a question about running a motor from a Raspberry Pi's GPIO via an L293D and hoped that somebody may be able to help me. I suspect it'll prove to either be completely nooby with a simple fix, or unresolvable because I broke something! I searched but couldn't find anyone with this specific problem.
When I connect everything up in what I believe is the correct manner I am able to run the motor in one direction (Pin 2 high, pin 7 low) but when I swap these the motor doesn't run. When running the measured voltage between pin 3 and ground was 4.85v and between pin 6 and ground 0.83v giving a difference of around 4v, enough to run the motor.
I have measured the voltages at various pins which look reasonable to me on the pins that I have connected -
1 (enable): 3.29v
2 (input1): 0v
3 (output): 0.17v
4 (gnd): 0
5 (gnd): 0
6 (output): 0.17v
7 (input2): 3.29v
8 (v source): 5.94v
9 (v logic): 3.29v
Everything seems much the same as when it is working in the other direction, except that the values at 2 and 7 are swapped over. Oh and I tried much the same thing connecting all the 3.3v pins to 5v on the Pi's output and the 0v control to ground instead, in case it needed more voltage - again worked in one direction but not the other.
I have pin 12 connected to my ground line which is connected to ground on the Pi and on my power supply. My power supply for v source is an old phone charger I chopped the end off supplying ~6v. My understanding is that I don't need to connect all 4 ground pins on the chip.
I simply don't know what the problem is. I tried swapping to using the 2nd set of pins on the other side of the chip and that showed the same issue - works in one direction only. I tried a different chip (I bought 2) and that one doesn't work at all in either direction. I wondered if I may have fried that somehow, and partially fried this one somehow. I'm not sure just how delicate these ICs are, I tried to be careful but I might have touched the pins to be honest. And I didn't ground myself or wear a wrist strap or anything like that.
If anyone can offer any advice I would be hugely grateful! I am a complete beginner so I've tried to provide all the information I can, but I understand I may well have missed something. Sorry if so - I'll try to fill in the blanks as best I can.
Thank you in advance!
Rob