This device detects mains and has tested more reliable than commercial models.
NOTE:If this device fails and you are hurt, i will take no responsibility. Test the device before use.
That said, this is what you need:
1)5 npn transistors
3)9v & clip
Step 1: Wire the Circuit
The circuit is simple.
Wire up using the picture below.
Step 2: You Are Done.
You are done.
To use it put the antena by the mains you will hear a buzzing sound from the speaker if they are live.
It should sound like this: