Using digital pin as ADC? Or Arduino with tons of ADCs?

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1

Hey guys,

I posted a bit ago about making a capacitive slider. I was able to figure it out and make it using the ADCTouch library. This library relies on the ADCs, but I'm wondering if I can input an analog signal to the digital pins and it would still perform the same actions? i.e. do the digital pins also have an ADC?

If not, is there an arduino I can buy that has ONLY ADCs? I'm thinking in the range of say 10-20 pins. 10 might be good enough, but the more pins the better.

The reason I need more is then I can add more strips to input into the arduino and achieve higher sensitivity. Also, if you're wondering I tried to use the CapSense library but found it was not reliable or repeatable enough to use and required too much external circuitry for my application. That is why I want to use the ADCTouch library with more pins.

Thanks guys!

2

Well, guess I should have googled more. Found out all I need is a multiplexer

3

From a software perspective it may be easier to use a few ATtiny processors. For example...

The ATtinyX61 family has eight ADC pins that do not conflict with the SPI pins. It has alternative I2C pins that also do not conflict.

The ATtinyX4 family has eight ADC pins but they do conflict with communications which would give you five ADC pins per processor.

4

The tiny 1634 and x41 have 12 and 11 (12th on x41 is on the reset pin)

5

The ATtiny828 has 28 analog pins. After allowing for the I2C pins and RESET that still leaves 25. But I wonder if it might be easier to work with multiple smaller chips.

6

Try CapacitiveSensor. Arduino Playground - CapacitiveSensor