Pictures from latest Heartbeat project:
PIC-chip sends serial data at 9600 or 19.2k speed direct to a PC or Linux box, without needing digital storage for the amplifier signals. Circuit-boards were created by a milling machine controlled by Extended Gerber files produced by gerb20.exe converting a fleXYcad circuit text file.
 

PIC chip a/d converter board ...	... is a milled board created from files generated by gerb20
detail from milled circuit board	D9 connector mounting hole
gerb20 8x6 pad-size option (in ViewMate) Red is copper, yellow is a drill hole. Not enough copper around the 3 lower drill holes.	gerb20 9x7 pad-size option More copper around the lower drill holes. Top holes are 0.040", lower holes 0.052"