/diy/ - Do It Yourself

>>1619587
>does it work
Well, the boost converter worked fine until I shorted the cap on one too many screwdriver and it stopped working. This was while the geiger tube was connected (via a large resistor), and I don't think the tube (SBM-20) will have been hurt, but for now it's just sitting half-complete on a breadboard. The actual counting circuit is a bit ambiguous, but last I remember I had one side of the tube grounded, the other side tied to the boost converter output via a 10M resistor, with a high-pass filter coming off the top of the tube. Pic related. The LEDs are to clip any voltage higher than 5V, because zeners are for nerds. Might need them going to the 5V rail too. I know during startup the high-pass will see a high-amplitude voltage spike, which I'm hoping to eliminate. I might feed the signal through one of my opto-isolators after the trigger if it looks like a good idea.
The output of the filter would either go to an amplifier then to a schmitt trigger, or straight to a schmitt trigger, feeding whatever MCU or FET+piezo or whatever I wanted. Probably an ATTiny85 with a small display on it, but arguably I could use a specialised frequency-counter+display driver chip. Like the one that's inside my function generator I guess, and since it has an int/ext switch for the counter, I guess I'll use it for the testing. Now that I have a decent scope (400Vpk max) I can likely get back on this project.

The boost converter itself was a comparator oscillator with the second comparator in the IC being used as feedback to shut off the oscillator when the voltage had been reached.