1 Channel 3V Relay High Level Driver Module Optocoupler Relay Module for ESP8266 Based Board

I needed a way to control the power on my prusa i3 mk3 printer with octoprint.Octoprint has a plugin named PSU.My octoprint is running on a PI 3B+.The relay runs on 3v.Perfect for the gpio pin on the PI.Works perfectly and I highly recommend this relay for the PI.

I bought 4 of these. ZERO of them work.Powering these with 3.3V and using a digital 3.3V output from an MCU, these relays show the LED blinking, but the relay does not switch.As others have said, these are defective. DO NOT BUY.

Super easy to use and worked great. I’ve had one in switching for a few weeks now with no problem on an RPi Zero

Took me quite a while to figure out why the relay wouldn't turn on (nor would the power LED). In the end, I found bad solder joints on the optocoupler input side (x1) and output side (x2). After remelting the joints, everything worked fine.For anyone trying to figure out what the jumpers are for... if you want to power the relay coil separately from your input signal (this is probably recommended since the relay coil draws more current than most 3v3 IOs are capable of, then remove JP1 and connect your separate 3v3 to the "relay side" of the jumper pin, then disconnect JP2 and connect your separate ground to the "relay side" of the jumper pins.

This particular model needs to be researched online when you receive it. You need to solder a connection on the bottom side of the board due to an engineering mistake with this board. Otherwise it will not trigger the relay. Works great once you get that part figured out..

Relay worked for 24 hours then stopped.

Perfect for a high-current output for an Arduino project

this was just what I needed to finish a project. worked like a charm. very pleased