Analog to digital converter

Discussion in 'Embedded Systems and Microcontrollers' started by shiva Raj, May 30, 2013.

  1. shiva Raj

    Thread Starter New Member

    May 29, 2013
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    I have started newly working with AVR microcontroller.I hve an variable analog input from a pressure sensor n i need tht in digital form..can any1 please help me where to connect that input n how to get accurate output using ATMEGA32,,....thanks in advance
     
  2. t06afre

    AAC Fanatic!

    May 11, 2009
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    Can you edit your post, and write full words. This is not Twitter or SMS. So you can use as many letters as you want.
     
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  3. shiva Raj

    Thread Starter New Member

    May 29, 2013
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    0
    I have started newly working with AVR microcontroller.I have an variable analog input from a pressure sensor and i need that in digital form..can any one please help me where to connect that input and how to get accurate output using 16 bit Analog to digital converter....
    thanks in advance
     
  4. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    Atmega32 has only 10-bit ADC, so you will need to get an external one if you need better resolution. What sample rate do you require?
     
  5. t06afre

    AAC Fanatic!

    May 11, 2009
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    We need to know which ADC and pressure sensor you will be using, and also which AVR. It will be most likely that the ADC use SPI or I2C like interface http://www.byteparadigm.com/applications/introduction-to-i2c-and-spi-protocols/ I am also sure Atmel have some app-notes about this topic. The pressure sensor will also most probably have a differential output. So using an instrumentation amplifier will be required. Do not try to build one your self.
     
  6. John P

    AAC Fanatic!

    Oct 14, 2008
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    And, I have words of caution to share: don't assume that just because you can measure an analog signal to 16 bits of precision, you will be able to get useful information. You need a very quiet electrical environment (i.e. good design, shielding, the right kind of filtering, quiet power supply) to make a 16-bit converter useful. If you have a hand-wired setup and you try to use this wonderful converter, you're likely to appear here again and ask "Why is my measurement so noisy?"

    A lot of people say measuring to 10 bits (1 part in 1000, roughly) isn't too difficult, but beyond that you have to work at it.
     
  7. WBahn

    Moderator

    Mar 31, 2012
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    Ditto!

    I think 10-bits generally is fairly easy, 12-bits isn't too terribly hard, but 14-bits is getting pretty challenging, and 16-bits can be a bitch.
     
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