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Detection of AC analogue signal — Parallax Forums

Detection of AC analogue signal

Donald WheelerDonald Wheeler Posts: 10
edited 2006-04-06 22:36 in BASIC Stamp
I am trying to have my basic stamp tell when a metal detector is showing metal. The signal from the speaker is incredibly nasty AC spikesfreaked.gif· All I want is a conditioner that gives a high with detection (Presence of signal). Any ideas?confused.gif

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-04-06 16:42
    Donald,

    ·· You could use a comparator or you could just feed the speaker output to the Stamp pin with a ZENER diode (5.1V we sell)·shunt to ground.


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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Donald WheelerDonald Wheeler Posts: 10
    edited 2006-04-06 21:51
    Two questions. On the comparator do I have to worry about voltatge difference between inverting and noninverting inputs being larger than 5V?smile.gif On the zener diode, which side shunts to ground?·confused.gif
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-04-06 22:36
    Donald,

    ·· On the comparator that really depends on which one you use and its specifications.· You can always clamp the input to the BASIC Stamp with the Zener.· This Diode is a 2 lead device with an anode and a cathode.· The cathode goes to the I/O pin and the anode goes to ground.· The end with the black ring/line is usually the cathode side.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
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