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IR signal question — Parallax Forums

IR signal question

dr hydradr hydra Posts: 212
edited 2015-03-02 11:43 in Propeller 1
I am looking at the IR kit from the object exchange. I am trying to understand how to use the propeller to send IR signals. The signal is modulated at 38K…however, looking at the IR_tx_nec spin file…the marks are set at 26.3usec total(I agree with) but the LED on is only 8.77usec…shouldn’t that be 13.15usec…half of the 26.3usec cycle??? What am I missing???

Comments

  • JonnyMacJonnyMac Posts: 9,105
    edited 2015-03-02 11:43
    I do quite a lot of work with sending and receiving IR signals. My strategy is to use a counter to create the modulation frequency, and then gate the modulation frequency by controlling the dira bit for the IR LED pin. This strategy works with active-high and active-low LED configurations.

    The Sony SIRCS protocol is one of the easiest to understand. I've attached my transmit object for it.
    spin
    spin
    jm_sircs_tx.spin
    25K
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