Infrared activator for LED sequencer

Discussion in 'The Projects Forum' started by allenpitts, Mar 5, 2011.

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  1. allenpitts

    Thread Starter Active Member

    Feb 26, 2011
    Good morning All About Circuits,
    Experimenting with led flasher and sequencing circuits.
    Have built several like the Velleman Wheel of Fortune\Wheel_of_Fortune_E_110126.gif
    and the Chaney sequencer which is similar to
    and this forum's excellent

    These are fun to look at but a draw back is that one must have special
    knowledge (although it is only where the switch is and how to operater it)
    for the viewer to see the effect. In a query to this forum Nerdegutta
    suggested Mondotronics
    Modulated Infrared Reflective Detector (MIRD) Schematic:
    as a means of activation with only the presence of the viewer
    to activate the circuit.
    So the challenge, before I spend my twenty bucks on the infrared
    detector, is to figure out how to turn the LED sequencer circuits
    on using the infrared detector.
    The Wheel of Fortune takes a momentary switch as shown in the schematic is the GIF
    listed above. I think it is a normally off momentary switch so I think
    a pulse from a 555 timer acting in the monostable mode would get the
    job done. True? Do momentary switches come in normally off and normally on types?
    But that is more speculation since the project I am actually trying to
    master is the ten LED sequencer shown at All About Circuits. The activating switch in the
    at All About Circuits, the Chaney and the 4017-7 above would be a simple on off switch where
    in the 4017 portion of the circuit that is connceted to the LEDs would be connected to the voltage continually and the voltage
    connection to the 555 would be switched. In this case the 555 would be
    operating in bistable mode and turning the 4017s on for a set period of time as the 555 goes between triggered and reset.
    So I went looking for a circuit to operate the LED sequencer when I happily discovered that
    there was already 555 activator in all of these the 4017 cicuits.
    The most important question is about my understanding of 555s. I believe
    the 555 in the 4017 circuits listed above is in bistable mode as in
    and the resistors R1 and R2 control how long the timer is off and how long it is on. True?
    If all that is true the question is how to the MIRD (infrared detector)to turn on the 555 timer operating
    in bistable mode whixh would then activate the
    sequencer. In the MIRD schematic above
    there is a 'Signal Out' node. Is the solution as simpla as connecting the
    Signal Out on the MIRD to pin 2 (trigger) and pin 6 (threshold) of
    the 555 timer?
    Allen in Dallas
  2. bertus


    Apr 5, 2008
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