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LED flashing/beating heart help/advice

Discussion in 'LEDs and Optoelectronics' started by carebare47, Nov 13, 2010.

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  1. carebare47

    carebare47

    66
    1
    Oct 21, 2010
    Hello,

    I was thinking of making a LED heart (maybe three concentric heart shaped rings of LEDs) that flashes/pulses/dims (or other patterns) for my girlfriend. I was wondering what pattern to use and how I would go about creating something that will do that. I know a little about astable flip-flop circuits and have tried to use a 555 timer before (didn't succeed last time, but I have improved much since then). I was going to build the final design on strip board. I could make one that just alternates two series' of LEDs but I was hoping for something a little more complex. Any and all ideas are welcome =)

    Many thanks,

    Tom
     
  2. RAMSELECTRONICS

    RAMSELECTRONICS

    14
    0
    Nov 4, 2010
    It's nice!
     
  3. carebare47

    carebare47

    66
    1
    Oct 21, 2010
    Help with the 'circuitdiagram.net/flashing-heart-circuit' circuit!!

    Hello again,

    Firstly, thanks for the links. I decided on the http://circuitdiagram.net/flashing-heart-circuit.html one. I have constructed the circuit on a protoboard (but have used BFY51 transistors as it is rather difficult to find and 2N3643s near me. Will the BFY51 still work? It seemed similar enough). So far I have only put a few LEDs in (to see if the circuit works before I construct it on strip board). There is one LED coming from Q1 (which flashes just fine), and two each from Q2 & Q3 (Q2 LEDs flash, Q3 do not). I am not really sure what the dotted lines on the schematic mean. If I connect these dotted lines then LEDs from Q2 & Q3 flash at the same time. If I don't, then only LEDs from Q2 flash. The Q2 LEDs are flashing at a frequency of about 1Hz (didn't have a potentiometer for R9 so I used a fixed resistor and improvised with 4x 4.7uF capacitors in parallel for the capacitors between pin 1&3). Also, the LEDs from Q2 don't flash on and off, they flash from bright to dim(ish). Any ideas? Could someone please explain these dotted lines? ^_^

    Many thanks,

    Tom
     
  4. barathbushan

    barathbushan

    223
    0
    Sep 26, 2009
    if you have a multimeter check the base of q2 and q3
     
    Last edited: Nov 19, 2010
  5. carebare47

    carebare47

    66
    1
    Oct 21, 2010
    The bases of both were fine, but the actual Q3 transistor was not. Tested it with my multimeter and it wouldn't give a hFE reading. Still don't really understand the dotted lines though. Swapped it with a working one and all is good. Now to order masses of LEDs and start transferring it to strip board =)

    Many thanks,

    Tom
     
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