the only problem i see is that this will be extremely complex. i can see using a few standard configurations and using CMOS analog switches to select component values, but to be able to arbitrarily "build" a circuit sounds more like you would need multiple crosspoint switches in addition to the component value selection switching. at least 5 pairs of crosspoint switches, one pair for each of the following: noninverting input, inverting input, negative feedback path, positive feedback path, and output. the crosspoint switches could be used to select one or more components (resistor, cap, etc) and also select where that component terminates (+V,-V,GND,block input, block output). even with that level of complexity, there still may be certain circuits that just can't be done, that would be much simpler to implement with a soldering iron...
Analog cross point switch matrix... that's EXACTLY what i intend to use. I also came to the same conclusion that it would be very complex. And i wouldn't have came and opened that thread if i didn't have a solution for this
. Basically, The user will still need to use a soldering iron to populate the components he needs on a "disposable plug-in board", that will look like a proto-board, more or less. The big advantage, however, is that user will not have to populate the wires: He will draw the circuit on PC, and then the wiring will be done by the device. He can rewire the circuit in 50 different configurations without having to touch the soldering iron.
I know that he will still need to use the iron again to choose different components, but at least, the use:
- won't risk having wiring mistakes (or the risk will be minimal)
- will be able to safely build 50MHz + circuits without having to worry about breadboard capacitance, long wires problems
- will be able to use SMT components (personally, that's one of my big problems, many times i have to solder wires to SOIC leads to be able to use it on my bread board...)
- and all the other advantages stated above...
To be able to make the circuit more affordable (maybe around ~70€) it can be a 14 node circuit (2 of them being VCC and GND). With the same design concept i have in mind, you can have around 8 resistors/capacitors/diode (any 2 leads components).
I took as a reference National Instrument's famous application-note 31, which shows basic op-amp circuits, and there are many circuits here that have far less than 14 nodes.
Anyway, i am defending my idea because it's the logical thing to do! but to be honest, i have my doubts about this project. Not technical, but doubts about whether one would pay 70€ for that. This kind of product has never been made before (correct me if i am wrong). It may be a top seller, and may as well be a big fail...