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Thread: Led run thru/through/threw/thrue a cap

  1. #11
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    where are you trying to go with this?
    lol...nowhere i guess...after all it wouldn't be very useful even if i did get it to work...but was thinking with caps/transistors/resistors and stuff maybe
    it could work (for just a challenge) ...but after many tests ... and no future point ...I'm on to the next horrible project

    About APA102... on my stair case seems I have a few bad apa102 chips in the string ...I replaced 8 or more and I must of ordered some poor quality ones
    the apa102's work great for about a month then one goes wierd causing the rest after it to not to work
    but I am getting good at replacing the bad ones
    The cause of the problem are unknown ....could be the vibration from using the stairs.
    and everytime I replace the bad apa102 it always seem that its the chip it self behind the led
    I am going to try ordering some good quality apa102 and replace the ones i have

  2. #12
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    that's not good... perhaps static electric discharges from carpeted stairs? [low humidity in winter...] - Did you put bypass capacitors on the power lines every few feet? [.1uf type...] and last - is your current / voltage well regulated. these small IC & LED units are a bit delicate... If you are having vibration effects it would often show in mechanical de-soldering or breaking of chip pin and such...

  3. #13
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    The approach in post #8 also works well if you use a two lead RG led instead of two individual LEDs. Will control R or G with only 1 Picaxe output. Output pin high gives one color and output pin low gives the other color. JimS
    Never too old to learn. LXXXV years old.

  4. #14
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    Did you put bypass capacitors on the power lines every few feet? [.1uf type...] and last - is your current / voltage well regulated
    @ premelec.... no I didn't add no caps ...good idea tho...when i replace both strings I will ...its run from a PC desktop power supply should be perfect power.
    I don't think its static ...but could be ....I keep my house well humidified...with a big cool mist one (one of the few things in the house I didn't LED it).
    never is there a bad solder joint that i found ...its all internal in the chip its self ...and its never the ones I replaced that goes bad....well so far anyway


    @ jims yes thanks ...makes colors closer ....but after all my tests trying different things ...I graduated myself from learning unuseful uses with it all

  5. #15
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    PC power supplies are meant to feed large currents and may not regulate well at very low current draw... You might run you lights at less than full intensity - up to 50% - or run them on 4 volts...

  6. #16
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    APA102 LEDs are on a SPI bus. If there is a dodgy soldered joint somewhere, all of the downstream LED may stop working due to lack of data.

  7. #17
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    @ premelec ...I do have the brightness turned down ....i think brightness is 0 - 255 ...and with out sensor being activated I think its running 20 and with activated I think its 180
    so when I get back home I will try to go full brightness (255) and see if that helps once activated...but I believe adding the caps would help the best

    @ inglewoodpete ..I understand on a dodgy solder joint ... i seen many solder joints look perfect and still fail ...but it doesn't seem to be any
    on the chip connectors from all the tests I did ...the reason I believe its the apa102 chip its self is after i replaced the bad chip then the strip works like brand new
    and after many tests with the bad apa102 chips on my bench I could not get them to turn on with a different picaxe and make sure its connected right and continuity etc

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