At that time it didn't even include an LED to give any visible information to the outside world. Today was the time to create a small LED-buzzer interface (if you can call that) for the muon detector for demo purposes. In the first coincidence detection prototype I built, I used a monostable 555 circuit to lengthen the (previously shortened) pulse form the GM tubes, since I had these 555s lying around. The GM pulse is shortened, because you can achieve more accurate coincidence detection that way, but for us those pulses are too short to see, they need lengthening. Since there will be a little beeper and 3 different LED signals (on 2 bi-coloured LEDs) plus a button in this project, I decided to use an ATtiny microcontroller instead of the 555s. The package is going to be smaller and it can source/sink the sort of current these LEDs or the buzzer need. Also, it's quicker to write some C code than going through the whole circuit design process just for some LED - buzzer - button business. I had an ATtiny44A lying around. It's a tremendous overkill for this project with its 4kb flash and 256B RAM. The code even with a little self test is less than 1 kb. Considering the size of the prototype case, this dip14 was the sort of size I wanted to solve this problem with.
The prototype is in the making, here's the a short video about the progress so far. This is the LED interface. The high voltage connectors are in the case, too.