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LED powering question

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PL1:
Disclaimer: I have not worked with the CDRs.

The low-profile rectangular buttons use a straight-pull to release instead of the the twist-to-lock switch-holder/LED-socket used by the round buttons. (or the twist-to-lock low-profile triangular ones)

Based on this pic by Louis Tully, the CDRs appear to have locking lugs of a similar location and size to the round LED buttons, but someone who actually has both would have to verify whether or not you can swap switch-holder/LED-sockets.



The downside if you can swap parts is probably losing brightness and maybe the evenness of the lighting (depending on how wide-angle the LED is) -- I recommend adding the second resistor instead.


Scott

j1345:
mvolke1:  How did you connect that to the LED buttons?  Can you detail that...  I'm trying to do the same thing.

mvolke1:
Hey Scott, you're right about the button differences. I emailed randy to see if he has a 12 lamp I could buy and replace. I'd rather do that than trust my skills messing with the existing lamp.

As for wiring, I ran wires from the hot, grouped them together with one of those twisty wire connectors and did the same for the ground. I cut the connector off an old 9v adapter and ran the hot to the hot and the ground to the ground.dies that make sense?

PL1:
:banghead:  Didn't think about this earlier, but you could just wire the two CDRs in series to drop 4.5v on each.

This will be the easiest way to wire it all together and keep everything well within the power supply specs.

9v ---- red wire - CDR - black wire ---- red wire - CDR - black wire ---- Ground
      |                                                                                               |
      ------------------------12v round LED button-----------------------
      |                                                                                               |
      ------------------------12v round LED button-----------------------
      |                                                                                               |
      ------------------------12v round LED button-----------------------
      |                                                                                               |
      ------------------------12v round LED button-----------------------
      |                                                                                               |
       And so on . . .

Wire the round LED buttons in parallel with prefab 0.250" daisy-chains if you have any.   ;D




Scott

RandyT:

--- Quote from: PL1 on October 20, 2014, 12:45:24 am ---:banghead:  Didn't think about this earlier, but you could just wire the two CDRs in series to drop 4.5v on each.

--- End quote ---

This probably won't provide the effect desired, unless the wiring is chained without removing the inline resistors.  These are what make them 5v. 

Running LED's at 12v is really inefficient, when there are not multiples in series, as the resistor needs to work much harder.  You can see this when using one of the online calculators.  The same LED which requires a 1/2 watt resistor at 5v, will require a 2 watt resistor at 12v.  In other words, expect it to get a lot warmer, as the differential between it's specified voltage and the supply voltage increases.

Something else to be aware of when running LED's in series is that the best case when one malfunctions, is that all of the units in series will stop working until the bad one is replaced.  Worst case is that you no longer have that voltage drop you were relying on, resulting in the destruction of the others in the series circuit.

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