Three IR Flashlights

If I want to modify the two IR set up to use three IR lights and sensors how would I need to hook up the second lead on each IR flashlight? In the two IR setup one is in D/A 0 and the other is in D/A 1, how would I do a third?


  • You could connect all the IR LEDs to the same D/A pin (perhaps all to D/A0), then add the extra IR LED's anode to a new Propeller IO pin.

    Set D/A0 to the voltage you require, which would be the same as you are doing for the example your posted.

    How it works...

    Provided each LED has a unique Propeller IO pin connection, you can still decide which one is active, by toggling those one at a time.

    Looks like P1 and P11 and the LED anode pins in your example. So maybe you connect a 3rd LED to P21! (Of course, the IO can be any one that you like you choose, and which is spare!)

    Just remember to ONLY toggle one at a time and it will work fine. (Ie. only call the freqout or pulseout command at 38KHz one at a time). If you wanted to call multiple LEDs at the same time, you'd need to investigate first if the D/A can handle the amount of current you'd need to sink to drive multiple LEDs simultaneously.

  • Ok, so if I understand you correctly I could hook multiple IR lights to the same D/A pin but I would just need to make they both aren’t pulsing at the same time? So in my attachment if I move the blue wire in D/A 0 to directly adjacent to the other blue wire then both the IR lights would be using D/A 1. If I don’t pulse both at the same time it would work? Then I’d add my third light to D/A 0.
  • That's correct.

    And if you needed the other DA channel later, you could drive all 3 (or more) LED's from the one DA channel. Provided you don't pulse them at the same time- exactly as you said it.

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