Thank you, that was the issue.

I purchased a few air pressure sensors that communicate via i2c and am not having luck with raspi detecting them. Running raspbien stretch on a raspberry pi zero W Here is device drawing: https://i.imgur.com/AXQntXn.png The device is listed as being able to take supply voltage of 3.3v or 5v. Here's ...

Adding the flyback diode fixed the problem, thank you! Responses below for future users that land on this post. Does the 24VDC for the relays and the RPi share a common ground or power supply? The Relays should isolate the RPi from the output contacts. The RPi and the power to the relay coils should...

I have an RPi 3 B+ hooked up to a 4 channel sainsmart 5v relay, and the relays are hooked up to three 24v DC solenoid valves and one AC 115v compressor. The relays have their own power supply so they are isolated by the board, and the 24v circuit has a separate power supply. The AC motor causes some...

I wrote a program to control some relays that switch electrical components like valves and motors on and off. I have buttons that send signal to raspi, then raspi switches the 5v relays. I am using npm 'onoff' to control the gpios and debounce the buttons. I have the buttons hooked up to common on o...