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DAC for Stamp — Parallax Forums

DAC for Stamp

FlorezFlorez Posts: 4
edited 2005-11-17 20:59 in Learn with BlocklyProp
What type of D/A Converter would be good to turn a digital signal from the stamp into a analog signal?

Paul Florez

Comments

  • Martin HebelMartin Hebel Posts: 1,239
    edited 2005-11-17 05:43
    Instead of a DAC, here's something to consider.
    The attached image is adapted from the upcoming Process Control text (to replace Industrial Control).
    By PWMing P2 you can control the output of the op-amp buffer from about 0.5V to 5V, and the RC filter only needs to be refreshed every couple seconds.

    The RC filter will give an average voltage of the PWM value, which will be buffered by the op-amp (LM358) for driving a small load. It has an 8-bit resolution based on the PWM instruction

    PWM 2, 128, 100 'output would be approx 2.5V.

    Sorry, haven't figured out how to insert images yet....

    -Martin

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Martin Hebel

    Electronic Systems Technologies
    Southern Illinois University Carbondale
    Personal Links - ·Lot of BASIC Stamp info
    and
    SelmaWare Solutions
    StampPlot Pro Version 3 Release 4
    Graphical Data Acquisition for your Micro and Imagination!
    Now allows additional controls to be added, or developed.
    298 x 181 - 6K
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2005-11-17 20:59
    Try a DAC0806 or DAC0804.· They're 8-bit jobs, but for a voltage out you'll need to add the current-to-voltage amp (the complete circuit is in the datasheet/s.)

    www.jameco.com/wcsstore/Jameco/Products/ProdDS/14912.pdf

    Jameco has DAC0808 (MC1408) for less than $2.

    They're not the last word in DAC'ing, too slow to do Hi-Fi audio or anything, but they're easy to work with, and understand, and not uber-finicky like.
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