solar powered Geier counter update

solar powered Geiger counter update

This has proven one of the most difficult things to solder together so far, no component is where I would like it to be, due to all sort of space restrictions, but in the end the wring and all the SMDs was possible:

I used the audio amp from the audio flashlight, simply broke of the relevant part of that PCB, and put it here. The big red HV capacitor sticks out, and to its left the logic level MOSFET that should switch of the Lipo battery below 3.2 V (IIRC).

Have not wired up the GPS module and fitted its power converter yet, that converter will be all the way on the right, and neither the SDcard, system is logging to the 24LC1025 (the 8 pin DIL).

Wiring side:

That blue thing at the bottom is a piece of coax used as HV capacitor to get some capacitance on the GM tube to work against the input amp. The SMDs have such low capacitance it did not work without some extra... The HV switcher transistor is top left, to its right a blue pushbutton that when pushed enables GPS (draws some more current). Note the plenty space left of the SDcard socket for its pullups and control. Organized a free I/O pin, and no longer is an transistor inverter needed I think. The big electrolytic and the sticking out transistors will probably stay that way, there is nowhere else space fro those.

BTW I did one optimization round on the asm software by replacing all goto-s by bra instructions and gained more than 500 bytes, so plenty of new stuff to add. The bra and preceding status register checks (still there for the gotos) can be replaced by brz bnz bnc ... Decided it was worth to actually read the 18F instruction set (datasheet), did not even know these bra things were there, just like I missed that tstsz or whatever it was, as it fell of the xpdf page, :-) So there is more space there for interesting things, but auto replace like goto by bra (only one goto remains, jump to interrupt vector), cannot be done here, needs tedious checking every instruction and testing again,. Anyways thing are taking form, until dropped probably...