Geiger Counter + Arduino

Hi guys, I've just received my Geiger Counter ( and I'd like to connect it to my Arduino Uno board. What I know for the moment is that when a radiation is detected, the geiger counter lights a led and a beep is produced with the buzzer. So, I'm thinking to use the signal that drives the led in input to the Arduino Uno but, for the moment, I'm a bit confused about hot to realize it. I'm thinking to use a Schmitt's trigger but I'm not sure that is the best way. Do you have some suggestions?

Thanks in advance!



Quite possible, there is a resistor somewhere in series with led, so you probably could trace it down and take a signal from other side of resistor (which is not side connected to led) and ground or “-” of the battery. Then you can attach this to pin 2 or 3 and count pulses with hardware Interrupt.
The only things, use a voltage divider ( two resistor ), most likely impulse is 9V.
BTW, what that chip on board, can you read a marking?

Hi Magician,
first of all, thank you for your prompt reply!
The chip on the board is a NE555N used probably in this way:
because the geiger counter works around 500V, the 9V battery is transformed from DC to AC with the NE555N and then a small transformer converts 9V AC into 500V AC.
So, in order to work, what values do you suggest for the voltage divider?

Thanks again!

Agree, if it’s 555, than it’s part of voltage converter circuit. I was hoping for regulator or OPA :stuck_out_tongue:
Resistor could be any value between 10k and 100k, in order no to affect source.

Thank you so much, I'll post the result as soon as possible!

Bye! ;)