Split one electricity cord over two appliances with different voltage inputs

[OptiGE]

I'm designing an enelctronic timer for a project. It's basically a box that will be able to break a 220V circuit, controlled from a phone or computer. It uses an arduino connected to a relay to achieve this.

Basically it goes like:

Wall socket --> box cointaining arduino and relay --> appliance (in this case a pump for an aquarium)

But right now I have two cords running to the box in the middle. One 220V cord that is connected to the relay and one to power the arduino. I would like for there to be only one cord.

How do I achieve this without using a power strip? (that would make the box very big)

 

[chopnhack]

But right now I have two cords running to the box in the middle. One 220V cord that is connected to the relay and one to power the arduino. I would like for there to be only one cord.

You could put a transformer inside your box to step down your 220vac along with a bridge rectifier and a voltage regulator to give you a steady 7-12 volts for your arduino. I would recommend to find a step down transformer that is intrinsically fused or add a fuse inline. That would give you one cord in. Of course you would have another cord to plug into the box to power your appliance.

 

[BobK]

How many conductors are in the cord? If it is 4, you are luck. You can get 120V by using either hot wire and the neutral. If it is only 3, you can't do that, it is not kosher to use the ground wire for return.

Bob

 

[OptiGE]

I solved it by copying what this man does in his video, just adapting it to the european style phone charger: