1-0 Ammeter

[trennonix]

Hello,

I want to build an AC ammeter that i want to interface to a pic micro.
It should be able to detect devices from 8 to 1000 W running on 220V.
I'm not actually looking to get any specific values, i just want to tell the chip if there's a device that is running or not.
I have an idea about how to detect that current: toroid inductor surrounding the wire that is carrying the current.
However, it is with the values\kind of wire\inductance\number of turns that i get lost and you guys come in.
It would be best if there are inductors that do just that and that i can get ready made from any local electronics store since spinning one of those is a pain...

Thanks

 

[smanches]

Search for Current Transducers on Digikey. They have clamp on ones so you don't have to rewire the main circuit.

They generate a small AC voltage directly proportionate to the amount of current. Just rectify and measure.

 

[mneary]

You can also look for Current Sense Transformers. Your local electronics store might have something like this. Here's an example.

 

[trennonix]

Thanks for your suggestions this is exactly what i was looking for.