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Need a 4 channel ADC... — Parallax Forums

Need a 4 channel ADC...

dennodenno Posts: 227
edited 2011-10-04 08:36 in General Discussion
Good morning...could/would someone direct me to a 4 channel ADC that doesn't cost $30 some dollars. Need the ADC to of course work or interface with the BS2sx.

Thanks....DenO

Comments

  • sylvie369sylvie369 Posts: 1,622
    edited 2011-10-03 04:37
    Did you check out this one? $4.73, and free sample PBASIC code on the product page.
  • FalconFalcon Posts: 191
    edited 2011-10-03 04:42
    ADC0834
    See Experiments with Renewable Energy page 26 for code examples.
    http://www.parallax.com/Portals/0/Downloads/docs/books/edu/Web_EWRE%201.0a.zip.zip

    falcon
  • dennodenno Posts: 227
    edited 2011-10-03 16:53
    Thank you for the info on the MCP-3204-B. I do have two questions about the chips usage.

    First, I have used the LTC1298, alot, and I was wondering if you still need to use the 1 Kohm resister between the data_in and the data_out pins like on the LTC1298?

    Second, does the Vref get tied to the 5 volt Vdd for the 5 volt reference or is a seperate reference voltage needed? I will not be measuring anything over 5 volts through the analog inputs. More likely nothing over 2.5 volts or 2500 mV.

    Thanks...DennO
  • kwinnkwinn Posts: 8,697
    edited 2011-10-03 17:32
    You can use Vdd or any lower voltage as the reference. If you use the 5V Vdd as a reference your range would be 0-5V with a resolution of 1.22mV per bit.
  • sylvie369sylvie369 Posts: 1,622
    edited 2011-10-03 20:14
    I have no idea about the resistor, but on the 3204 you can use Vdd for your Vref. If you're sure you're not going to exceed a certain lower voltage, you can use a voltage divider to give a more appropriate Vref taken from Vdd.
  • ercoerco Posts: 20,259
    edited 2011-10-04 08:36
    Some $4 processors have 11 ADCs built in, no interfacing required.
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