I am planning to try multiplexing additional analogue inputs through a decade counter and an opamp in a summing configuration -
1) Decade counter outputs are connected to pots
2) center tap of the pot is connected to the opamp summing circuit
3) only one counter output is high at a time, so (hopefully) the summing circuit will output its value
Lots of assumptions on my part namely
Assumption 1: low outputs are effectivley grounded
Assumption 2: grounding one or more of the inputs does not impair the summing circuit
I know there are dedicated parts available I am just hoping to build something from the parts I have today and this seems viable.
Speed is not important in the given application, accuracy within several % is also fine.
Any comments or well know alternatives using generic components ?