[Mike Copioli]

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Originally Posted by marcan

The digital pots do look like a good solution, and they're not too expensive either. Specifically, these (from Microchip, hah) look like a pretty good choice at $2.65 each (we'll probably use three or four of them to give 6 or 8 inputs).
http://www.digikey.com/scripts/DkSea...604125&Site=US?

http://ww1.microchip.com/downloads/e...Doc/11195c.pdf

If you choose to use the digital pots, make sure you read the data sheet very carefully. They have a tolerance of +-30%. So that means you could get a pot that has a value of 70k to 130k. Also in order to use the pots you must interface the to a device with SPI or I2C. Another words you will need a processor. Processors need power, usually more than the 10mAs supplied by the digital outputs. In short you will need an external power source, which you know, is illegal. This is one of the difficulties that we were faced with when developing the Chicklet.