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best way to control 20 photoresistors — Parallax Forums

best way to control 20 photoresistors

ouconvertouconvert Posts: 17
edited 2006-02-22 07:13 in BASIC Stamp
I need to read 20 photoresistors and be able to view·anyone of them at any given time. i assume i would need 20 input pins to be able to do this, i will also have a push button in there so I would need 21 if i assumed correctly. what would be the best stamp module or combination? Im looking for the most simplistic route, with cost, complexity, etc. thanks.
sean

Comments

  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-02-22 06:48
    Well, you certainly don't have 20 inputs on the BASIC Stamp so you might consider using multi-port ADCs, or some sort of multiplexing scheme using analog switches.

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    Jon Williams
    Applications Engineer, Parallax
  • ouconvertouconvert Posts: 17
    edited 2006-02-22 06:55
    where could i start learning about using those?
  • Bruce BatesBruce Bates Posts: 3,045
    edited 2006-02-22 07:13
    ouconvert -

    Merely by way of example, Analog Devices AD7490 is a 16-Channel, 1MSPS, 12-Bit ADC which only requires 4 pins for synchronous serial access (SHIFTIN/SHIFTOUT). Here is the Analog Devices web site:
    http://www.analog.com/en/index.html

    Regards,

    Bruce Bates

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