I am looking for a simple, low cost solution to control on/off of mains supply to certain equipment. The control will be done using one of the output pin of Arduino Uno.

The input trigger and how to control it is application dependent. e.g. controlling an equipment or controlling supply to section of home but in principle mains control module implementation remains same. So looking for solution which is safe while doing connections as well as while in use in indoor conditions for years.

  • 4
    Your question brings up an important point: make sure you know what you're doing because anything that involves mains is potentially deadly. While you are specifically looking for something safe, you will likely have to tweak and debug it, which won't ever qualify as safe. If you're just trying to do something useful or didatic with your Arduino, please choose something else to play with. Prefer to power your stuff with a quality wall wart or ready-made power supply.
    – Ricardo
    Commented Feb 15, 2014 at 14:32
  • 2
    I don't mean to be rude, but your question seems to lack research. Have you google for a solution? Did you find anything similar to what you're looking for? If you found something but it doesn't quite serve your purpose, show us and tell us why. Share your research with us.
    – Ricardo
    Commented Feb 15, 2014 at 14:38
  • 1
    I second Ricardo's comment. Handling mains in any way can be extremely dangerous. Do not do so on your own just for the sake of experimentation or if you haven't handled mains before. The smallest mistake can result in major damage, in more ways than one.
    – asheeshr
    Commented Feb 15, 2014 at 14:49
  • >Have you google for a solution? OK I should have mentioned it in first place. The googled solutions where on the lines of playground.arduino.cc/uploads/Main/relays.pdf. Which I thought not safe while assembling as well as in use, as typically putting everything in box in home might not be temperproof. So looking for solution which is actually takes care of issue pointed by Ricordo and Asheesh.
    – Rajendra
    Commented Feb 15, 2014 at 17:25

2 Answers 2


The PowerSwitch Tail 2 is a great way for experimenters to control mains voltages. It is insulated and internally decoupled, so you only have to hook up 5v, gnd, and a signal line to control it.

This model supports only 120V, but there are also kits for 230V.

enter image description here

image from sparkfun

  • Safe but not cheap. But +1 for addressing safety over cost.
    – Ricardo
    Commented Feb 15, 2014 at 15:47
  • Note that this model supports only 120V (US) whereas the OP needs a solution for 230V. Might be good to look for an equivalent for European market.
    – jfpoilpret
    Commented Feb 15, 2014 at 17:11
  • 2
    Oh, right. EU version here
    – TheDoctor
    Commented Feb 15, 2014 at 17:31
  • Thanks TheDoctor, I am looking for this kind of solution.
    – Rajendra
    Commented Feb 15, 2014 at 17:33
  • 1
    That link points to a page with US and EU kits
    – TheDoctor
    Commented Feb 15, 2014 at 17:35

Playing with mains is dangerous - so best to use a kit designed for that purpose. Be careful with units designed in the US - their safety requirements are a bit different from UK and Europe.

For example the Power Switch Tail kits do not include a fuse - if the appliance being controlled goes faulty and starts drawing a bigger current, the switch could burn up.

Here is one designed with Uk safety features in mind:


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.