Prototype USB to ST4 guide output
PIC based (18F2550) for USB interface as CDC interface (USB-serial port)
Use same ASCOM driver as the native USB-TTL serial 909 clone for guide control
Opto-isolated from scope
Update 5/13 PCB arrived, all works fine!
Shown with open collector chip PS2501-4
Same socket accepts 2 TLP227A-2 photo mosfets for solid state relay at higher costs
Update 5/1/2009, PCB ordered
Relay adapter board, plugs into socket of PS2501-4 chip
Anything or nothing may change in the future, this does work built as shown
Prototype parts list, note PS2501-4 now used, not PS2502-4
Prototype schematic (as built) (click on pic for full size PDF)
Note: change from below, RB7 is now RA3 in PCB version (SW2 to RA3)
Pic of first draft top layer PCB, no room for the led's yet. 25x400 mm
