First time poster, here - thanks for keeping up this great resource!
I'll get right to it...
[u]My goals (using Arduino)[/u]
- Replacing 20 (40 for stereo) analog pots with digitally controlled pots
- Ability to read DCP settings on an LCD.
- Ability to store settings for recall.
I am only mentioning 2 and 3, in case they impact the solutions for 1. If not, Ill leave them out completely for now if not.
I know nothing about digital, and I am just looking for advice to make some purchases and get started with some experiments.
I'd like to use the AD5291 DCP. It seems to meet my basic requirements, which are precision (1%), and at least +/-15V operation.
Alternatives are welcome, but I figure Ill get a dosen of those to get me started.
[u]Choosing the right Arduino (and mystery parts)[/u]
I need to interface 20 pots. I am worried it will represent an awfully high capacitance build-up on the clock and data transfer ports.
Eight of the pots I am replacing are actually 4 x 2 gang pots, which means, they will never need separate control. At first, I thought this would mean I could just put them on shared SS pins to pull two low at once, but that was a dead end.
I considered daisy chaining all pots in pairs of two, so I am left with 10 x 2 in parallel. After doing a bit of reading, I get the impression that daisy chaining can be finicky, and I dont know if mixing parallel with serial that way is even possible - It also takes 32bits of code to interface the daisy chained pots.
For multiplying available ports, I have come across multiplexing, but I am blank as to which device to look at.
If I weren't worried about potential problems running 20 SPI devices in parallel, I would just get a MEGA board to have plenty of ports. I am not above brute force solutions.
I would really appreciate some help getting started, and getting some parts home.
Half a dosen AD5291 An Arduino xxx? And?