I currently have 4 Pi's, soon to have 40. I have them setup to take a picture when a signal is detected via GPIO. Individually they work.
I connected the pins on all 4 to one wire, and the grounds on all 4 to another wire. Then connected the wires and only one took a picture. I then broke it down and added one Pi at a time. Up to 3 worked, but the forth one threw it off again.
The weirdest thing is, I took the pin from the 4th Pi off the chain, and tried to get the first 3 to work again, and only the 4th Pi took a picture... Even though its ground was the only thing connected Where am I going wrong here? How can I trigger them all with one button?