DIY a Geiger Counter

It's very easy to build a geiger counter from various parts.

A Geiger counter consists of a power supply, a tube containing a gas that ionizes when a particle passes through it and a speakeror even a galvanometer.

The first thing to do is to buy a Geiger tube. Do not try to make one.

The main difficulty is that we must supply it with "high voltage".

To resolve this problem, I bought EL-Wire.

http://en.wikipedia.org/wiki/Electroluminescent_wire

Electroluminescent wire (often abbreviated to EL wire) is a thin copper wire coated in a phosphor which glows when an alternating current is applied to it.

The first step!

On ebay, we can find a EL-wire for under 10€, and it works with two batteries of 1.5 V = 3V!

With 3V EL-Wire power supply, we are left with 125Vac 1kHz output (remove EL-Wire).

There remains to add a Dickson multiplier (parallel capacitor voltage multiplier)

With the tube that I bought, I need 700V (it's a 6107/bs212 tube).

The diagram below is enough and easy to build. (Blue: EL-Wire power supply, black: Dickson multiplier)

Dickson multiplier:

3x capacitor = 4.7nF 4kV

3x Diode = 1N4007

Direct test with piezo speaker!

I was advised on my tube, the power to 500V. So I added a 10Meg resistor to load the output of my power supply. I am now below the 650V.
To test my geiger tube, I first started looking at the pulses with an oscilloscope to the legs of the resistance of 10M connected to the case of Geiger tube.
Then I connected a Piezo speaker with resistor 1k.
We hear many clicks! ;) About 5 clicks per minute! The background noise!
It's not a good idea to connect a piezo speaker direct to 10Meg that prematurely ages the tube.



Add an Arduino!
I remove le piezo speaker and add piezo buzzer and arduino mini pro ATmega168 16MHz.
Now the arduino is programmed as a monostable.
Each ionization, a 50ms beep is emitted.

------------------------------------------------------------------------
/*gm code Arduino beep */
//pins
const int GM=3; // IN
const int beep=8; // out buzzer

//variable
long countGM = 0;

void setup() {
pinMode (GM, INPUT);
pinMode (beep, OUTPUT); // Buzzer

// demarrage des interruptions
attachInterrupt(0, GMcount, FALLING); // IT sur PIN2
digitalWrite(beep, 0);
}//fin setup

void loop() {
  if (countGM !=0)
  {
  digitalWrite(beep,1);
  countGM=0;
  delay(50);
  digitalWrite(beep,0);
  }
}// fin loop

// interruption
void GMcount()
{ countGM=1;}

------------------------------------------------------------------------

To be continued... and thank you Google translate ;)
F4EGX - 5 october 2011