With Instructables you can share what you make with the world, and tap into an ever-growing community of creative experts.
Tell us about yourself!
This provides absolutely no isolation from the mains except via the relay. If the relay fails and shorts internally to the 5v your Arduino will be at 120V on the VCC supply line because the opto-isolator is not being used correctly (VCC on both sides of the opto-isolator making it useless). You need a separate 5v supply on the JD-VCC pin instead of the jumper.
Let your inbox help you discover our best projects, classes, and contests. Instructables will help you learn how to make anything!
© 2016 Autodesk, Inc.