Electronics make our life very easy but i never thought it can save our life too.
In this my project i show how to save our life from electric shock.
This project is very simple,Its turn off main switch or cut off power if you bi-mystically touches high voltage power line.
Step 1: Principle
Human receive a electric shock when he or she is part of part of electric circuit.Human body resistance changes with person to person and several more environmental condition.But normally dry skin resistance is near about 100K ohm.
if you came contact with 230V AC voltage(RMS 160V) ,as per ohm low the current flow from your body is
I=160/100K (R=100K human body resistance)
This small current sense by transistor and switch the mains power supply off by using RF link.
Step 2: Schematic Dig. of Transmitter Section
We saw the purpose and principle of project,Now lets understand its exact working.
9V battery used as power supply for the project which is connected via IC7805 to regulate constant 5V supply.
The BC107B act as a switch.The BASE terminal is connected to human body.At COLLECTOR(C) terminal +5V supply is provided and EMITTER(E) terminal is connected to the DATA pin of 433MHz transmitter.433MHz transmitter powered by 5V vcc.
Even small(1mA) current through BASE terminal is enough to conduct collector to emitter current.Which produce DATA signal at the DATA pin of 433MHz transmitter.
Step 3: Schematic of Receiver Section
433MHz receiver power up by +5V supply.The DATA pin of receiver is connected to the BASE terminal of transistor C2073. If DATA is present then it cause to produce current from C to E otherwise remains ideal.At emitter terminal 9V relay is connected which operates when +9V are applied across it and then it switch from NC(normally connected) to NO(normally open). At initial condition relay is always in NC condition,means the mains power supply is connected when it shifted to NO it cut the power supply.
Step 4: COMPONENTS
Step 5: Lets Make It
Start with receiver section.
place component one by one.
place all components and solder it as per schematic dig.
Step 7: How to Make Safety Belt(transmitter Section)
find belt and buckle from old bag pack.
Lock the belt in buckles in such manner that it can be wear on wrist.
ok its ready.
Insert the Base terminal of BC107B from top of the belt.
and bend it with parallel to belt surface.
so it can easily comes in touch with human body.
Insert 433Mhz transmitter in socket.
Arrange all circuitry as per schematic and place on a belt
i use wire and glue for fixing it.
you can use anything
Step 15: How to Make Antenna
use 50ohm wire to make coil of 6.5mm about 20mm length.
sorry,i forgot to clicks photo at the time of making antenna.
but you can make it with help of google.
Step 16: How to Test It
connect 100K(2W) resistance terminal to the base of BC107B and another terminal insert in 230V AC mains plug.
take precaution while testing, use insulating gloves.
At receiver side use bulb to connect in series with 9V relay and observer it.
when you connect resistance to mains power supply the bulb turn off.