🔌 Enhance Arduino Projects with Channel Module Trigger Optocoupler Review

I am using this with two Raspberry Pi boards (one 3B+, the other 2B) both connecting 5V to power the magnet board and the PI 3.3V GPIO for in/out Use power off. One of the 4 devices was defective immediately, but the others work. For the money they are a good choice. Note that there is a hard limit to the current available to switch GPIOs from the Pi, so a single-channel model would be the only viable choice. I can use it to turn the 3D printer on and off by turning on the AC power. with the…

After a little searching it's actually pretty easy to use. The spec is terrible, but the manufacturer put these relays on a breakout board that allows you to use a HIGH or LOW signal to activate the relay. I'm using mine for a cool project with a temperature controller that turns on a fan or heating element depending on the temperature. Rated for up to 250VAC, they use an infrared optocoupler to isolate the digital control circuitry (lower voltage) from the analog output (higher voltage). Very…

Typically an optocoupler is used to isolate the input signal from other signals on both the high and low side. This circuit uses a common ground between input and relay power, which doesn't make sense to me. So the optocoupler protects the input signal from the back EMF of the relay, but I can use a 0.1 cent diode for that. I modified the circuit so that the input side of the optocoupler is isolated from this circuit, then I am driving a circuit that does not share a common ground with this…