I am trying to recreate the sort of microchips that are on printer cartridges so that I can make cartridges that can have their data programmed and read? I only need to store 8 bits, so I was thinking a microchip might be overkill. How can I get 8 bits of data from a cartridge that is plugged in?
I was also thinking of simply connecting power through a switch (0/1), representing the bits. This would be connected through a pull up resistor and so where the switch was closed, you would get some voltage reading.
Another design I thought of can differentiate 16 distinct currents based on 4 switches and 4 strategically chosen resistor values. The switch being open represents a zero. The current was equal to the bit value (ie. switches being closed in 1010 gave 10ma of current). How reliable then is current ADC and would it be easy to repeat this for several cartridge holders?
Anyways, these are the potential solutions I have been thinking of today. Let me know if you all can think of another solution for differentiating between cartridges when they are plugged in.
Excuse the many tags but the solution could potentially be in any of these categories.