Fingerboard LEDs

Discussion in 'Luthiery, Modifications & Customizations' started by foreright, Apr 12, 2013.

  1. foreright

    foreright SS.org Regular

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    Hi all - I have a question about the practicalities of using fingerboard LEDs.

    I ask as I'm having some issues finding LEDs that are small enough height-wise to fit "in" a fingerboard... Originally I had planned to use 5mm LEDs but those are typically pretty deep - usually around 9-10mm not including the cable so I can't see that they can be used which leaves me looking at 3mm ones. Now even these are typically 5-6mm deep, which leaves a little margin for error as the fingerboards I use are typically 7mm thick. Actually, given that I plan to use "domed" LEDs, I would be sanding the top flat once they are installed which should remove a little height.

    Q) Has anyone come across any "low profile" LEDs, preferably with a flat top, or is 3mm "normal"?

    If I use the typical dot configuration (ie. single dots aside from two dots at 12 and 24) I end up with an array of 12 LEDs. The LEDs I have to test with are blue and have Vf=3.2v, If=20mA. So by my calculations, if I pair them in series and connect the pairs in parallel with a resistor for each pair, the whole array consumes 104mA, assuming it's powered from a 9v battery.

    Now given that a typical 9v alkaline battery has a capacity of approx 600mAh, that only gives me a battery life of 4 hours or so right?

    Q) Is this normal/expected as this sounds pretty short to me?..

    Of course, I could go down the route of running two 9v batteries in series but it sounds kinda silly to be running multiple batteries just for LEDs!

    Lastly, I will be running fibre optic cable for side dots also (powered by a single LED in the control cavity. The stuff I'm using has a pretty small bend radius - I wonder if it would be practical to use this for the front facing dots also - anyone tried this?
     
  2. sibanez29

    sibanez29 Si

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    Fiber optic cable all the way. Only one LED is needed, and color can be changed with the bulb. If the led dies, just replace it rather than having to remove the entire fingerboard. Also, I personally feel that face dots as LEDs will require the removal of too much of the fingerboard due to the wiring, especially when coupled with the fiber optic cable for the side dots. Just my opinion.
     
  3. foreright

    foreright SS.org Regular

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    Agreed - actually one plan was to use a multi-coloured LED with a selection switch for the fibre optics. I would say however that with regard to how much material is removed from the fingerboard, it's not actually that much. Besides, once the wiring is installed (and tested!), the cavity will be filled with epoxy so I'm not sure this is a concern...

    The problem with fibre optic cable for face dots is that the bend radius increases rapidly with the diameter... for example, 1mm cable has a min bend radius of approx 5mm, 2mm has a 25mm radius, 3mm has a 40mm radius.

    Would a 1mm illuminated face dot be big enough?
     
  4. Pablo

    Pablo Resident Wanker

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    I would suggest using a regular face dot with a small hole for the 1mm fiberoptic cable.
     
  5. sibanez29

    sibanez29 Si

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    I would probably use 1.5 mm cable if you can find it. Bend radius is something to experiment with, as some light decrease may not even be noticeable. Here is an excellent demonstration of installation (part 2 is linked within the page):

    How To: Fiber Optic Side Markers Part 1! - TalkBass Forums
     
  6. foreright

    foreright SS.org Regular

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    Yep I have seen that tutorial before - very good explanation and that is exactly the way I plan to do it although I had planned on putting the channel on the treble side for various reasons. I think 1mm is probably best for the face ones as I suspect that even 1.5mm would have a min bend radius that is too big unless you thread it through the face at an angle.

    Time permitting I'm going to do some experimenting this weekend with some ebony off cuts and the 1mm fibre I have knocking around in the other room :)
     
  7. foreright

    foreright SS.org Regular

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    Ok, I knocked together a quick test this afternoon as it's raining outside - there's two sets of fibre here... all the fibre is 1mm but two of the fibres thread through a blue plastic tube although that's hard to see in these pics...

    Unfortunately the blue plastic tube was stained slightly by the ebony and is not really all that visible. Regardless I quite like the look when the dots are not powered!

    [​IMG]

    [​IMG]

    [​IMG]

    What d'ya reckon?
     
  8. pondman

    pondman Build Whore.

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    Looks good to me , I've been wanting to know how to do this properly for ages :yesway:
     
  9. sibanez29

    sibanez29 Si

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    Very nice! 1 mm always seemed too small to me theoretically, but it looks plenty big enough from the pictures.
     
  10. BlackMastodon

    BlackMastodon \m/ (゚Д゚) \m/ Contributor

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    I think that looks pretty great! Does each dot have to have it's own LED/wire?
     
  11. foreright

    foreright SS.org Regular

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    Hey, they are fibre optics - single led powers them all :)
     

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