The firmware for the electronic stamp is downloadable here:
A movie of me using an earlier prototype (using another kind of cartridge) is
The pinout of the cartridge seems to be mis-printed in the magazine (amongst others,
R3 is missing)
so here is the correct pinout of the model 40 HP-cartridge:
Pinout cartridge. Seen when looked at the back of the
cartridge, with the printing head pointing downwards.
R0-7 en C1-4 are used in the schematic, the rest isn't.
© Jeroen Domburg