Electric shock protection and short circuit detector circuit

[PersianMan]

I need to a simple circuit for detecting electric shock by a micro controller etc.
Please refer me to a project.

 

[Gobbledok]

Being shocked isn't enough to detect it?


I mean to say what sort of electric shock do you need to detect? What is being shocked and what is it being shocked by?

 

[PersianMan]

Being shocked isn't enough to detect it?


I mean to say what sort of electric shock do you need to detect? What is being shocked and what is it being shocked by?

Dear friend,
Thanks for your reply.
I mean a electric shock to human body.

 

[Gobbledok]

Dear friend,
Thanks for your reply.
I mean a electric shock to human body.

Hmmm.... I can't actually think of a way to detect an electric shock to the human body.

Are you talking about a large, mains-powered electric shock or a small static discharge ?

 

[PersianMan]

Hmmm.... I can't actually think of a way to detect an electric shock to the human body.

Are you talking about a large, mains-powered electric shock or a small static discharge ?

Dear Gobbledok,
I mean mains power 220v 50Hz.

 

[Gobbledok]

Ah I think you a safety switch for your house, correct? If you do, it's called an Earth Leakage Detector. Also called a Residual Current Device.

It's not really a project you can do, it has to be installed to your meter-box by an electrician.

 

[Hero999]

A neon lamp.

Connect a high value high voltage resistor in series (between 470k and 2M2, 2kV) and it will glow when one lead is connected to a dangerous voltage whilst you're holding the other end. Don't worry, you won't get a shock because the current will be so low you can hardly feel it.

 

[PersianMan]

Dear Gobbledok,
Indeed i don't know it's name exactly. Yes, Indeed it for a switch but not for my house. I designed a smart switch controllable remotely and i want to add this capability.
I want to release the relay of smart switch since detecting the earth leakage (connection of Live line to human body). Exactly i want to send a signal to a microcontroller (AVR ATMEGA16). Just i want a circuit that detects the leakage and inform it to a microcontroller.

Dear Hero999,
Thanks for your help.
According to above comment, No need to holding another end (i mean neutral line). Just someone hold live line and is shocked because he/she is on the ground.

If there is a common solution for this problem in safety switch, What is it? How about short circuit?

 

[PersianMan]

Dear Friends,
Is there a Hall Effect sensor usable for 220vAC input?
Is it usable to measure the current and decide to release the circuit or not?
If it's possible, We can solve the problems of short circuit and earth leakage.
I think we can measure the current by voltage divide for detecting the problems. Is it suitable for it?

 

[Hero999]

Why not buy an RCD (GFCI in the US) which will be tested and guaranteed to disconnect the power before you die, rather than lashing something together which won't be so safe?

 

[olly_k]

Sounds like he wants to electrify a doorknob and be notified if any people / 'crooks' decide to try and open it / 'break in'...?

 

[Gary B]

I see that you are going to have a problem with this project because a human body is not unique. Skin resistance varies from person to person, weather, time of day and other sources of resistive shorts can have the same current profile.

Probably the best thing you can do is detect a current imbalance in the mains. If you bring a pickup loop near a wire caring a current, it will induce a current in the loop. If that same loop is in the field of the return wire as well, there will be no current detected because the equal currents flowing in opposite directions will cancel out. However, if something shorts one side of the line, like say you were to jam a metal coat hanger into one hole of an outlet while standing in a metal bathtub full of water in the rain, then some of the current will be flowing through you instead of returning down the other wire causing a small net current in your detector loop that you can use to trip your device. Sensitivity will be controlled by the size of the pickup loop.

Of course, this is not UL approved and should not be considered as adequate protection of human life.