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RPM read — Parallax Forums

RPM read

anita1984anita1984 Posts: 23
edited 2009-06-22 16:32 in Propeller 1
Hello forum , can someone guide me to connect IRL80a and IPT80a to the propeller ? I am using them to read the RPM of a motor .
Thank you in advance.

Comments

  • LeonLeon Posts: 7,620
    edited 2009-06-22 16:32
    Assuming that they are an IR LED emitter and photo-transistor, you just put a suitable resistor in series with the LED and power it from 5V or 3.3V, and connect a resistor (2k2, say) between the collector of the photo-transistor and 3.3V, and connect the collector to an input pin on the Propeller. If you get noisy transitions, use a 74HC14 Schmitt trigger to clean the signal up, or do it in software.

    Leon

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