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Looking at the schematics of the Intel Edison mini breakout board, there are no pins for analog inputs, e.g. for reading state of a potentiometer.

For a hardware workshop based on the mini breakout board, I am thinking to discuss analog inputs. What circuit or breakout board would provide analog-to-digital conversion in a "cheap" way? What about power rails for the ADC? I2C on the Edison has 1.8V while system voltage can be higher but is not stable/accurate enough for ADC maybe?

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Use an external ADC connected to one of the digital interfaces of the Edison, for example I2C. Sparkfun sells PCBs that are designed to attach to the Edison in a stack, and here is one for a 4 channel (single ended, 2 channel differential) Delta Sigma 12 bits ADC. https://www.sparkfun.com/products/13327 I haven't looked around, there might be cheaper alternatives.

Nothing prevents you from making you own "edison block" with other ADC chips / analog multiplexers. It's probably cheaper, but very often your time is more valuable than a 10 dollars savings.

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  • \$\begingroup\$ thanks, there is are brd and sch files provided too: github.com/sparkfun/Edison_ADC_Block/blob/master/Hardware/… - that is KiCad ? or how to read these on a MacOS ? subquestion might be how to do ADC on a bread board - 20USD to explain an ADC is not so cheap, but maybe an option indeed \$\endgroup\$ – poseid Jan 2 '16 at 13:09
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    \$\begingroup\$ It's Eagle. As I said you can make a breadboard yourself with components bought off Farnell, RS, Digikey, Mouser and such for a fraction of the price. To be on the safe side you could clone that board on a breadboard as everything is already available. Not sure what the cost saving would be though. \$\endgroup\$ – Mister Mystère Jan 2 '16 at 13:11
  • \$\begingroup\$ something on tindie which might work: tindie.com/products/SparkysWidgets/12-bit-adc-breakouti2c/… \$\endgroup\$ – poseid Jan 2 '16 at 13:59
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    \$\begingroup\$ You can use any I2C device as you want, however pay attention to the fact that you may need a level translator: the Edison operates at 1.8V. If your device has integrated pull up resistors and does not allow 1.8V in its supply range, you will have to translate from whatever supply voltage your ADC operates at to 1.8V. \$\endgroup\$ – Mister Mystère Jan 2 '16 at 14:41
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From documentation (https://www.arduino.cc/en/ArduinoCertified/IntelEdison#toc3), you can see that the ADC for the Intel Edison Arduino board is an SPI-based chip on the board and is not present on the mini-breakout board. Thus, as mentioned above, you should go ahead with an external ADC.

According to the Arduino board schematic (http://www.intel.com/content/dam/support/us/en/documents/edison/sb/edison_arduino_hvm_8_26.pdf), the ADC used is the ADS7951. Perhaps you could use this externally and recycle the MRAA ADC library.

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