How does one make light up knobs on a pedal?

[steveyraff]

Done a quick google search of this and I'm yet to find an answer.

I am presuming its just a clear acrylic knob, with an LED under it.

Two questions I have about this - firstly, how do you mount the LED to the enclosure? I can't quite work out how to do this so that the LED is flush with the enclosure surface and up until now, I've only ever built pedals using LED bezels.

Secondly, I can't figure out how the light would seem centred under the knob, considering it would have to be considerably off centred to allow room for the shaft of the potentiometer. Seems tricky fitting an LED so close to a potentiometer in general.

Thanks for your help guys,
If there is a guide about this elsewhere on here that I've failed to find myself, please link me to it.

Cheers.

[italianguy63]

http://www.diystompboxes.com/smfforum/index.php?topic=109326.0

This is one way.  But, potentiometer values are sometimes limited.

MC

[Brisance]

Now to think of it, one could probably drill through the center of a pot without hitting anything vital, but getting metal shavings in your pot would mess it up, so utmost care should be taken.

[roseblood11]

It has been done by a user named "haddock" at the musikding.de forum. He posted a good tutorial, but the gallery is down at the moment.

[PeterPan]

Done a quick google search of this and I'm yet to find an answer.

I am presuming its just a clear acrylic knob, with an LED under it.

Two questions I have about this - firstly, how do you mount the LED to the enclosure? I can't quite work out how to do this so that the LED is flush with the enclosure surface and up until now, I've only ever built pedals using LED bezels.

Secondly, I can't figure out how the light would seem centred under the knob, considering it would have to be considerably off centred to allow room for the shaft of the potentiometer. Seems tricky fitting an LED so close to a potentiometer in general.

Thanks for your help guys,
If there is a guide about this elsewhere on here that I've failed to find myself, please link me to it.

Cheers.

First, for the pots with LEDs built in, I'd say fabricating them from existing pots is going to be a frustrating challenge. Someone may have them already, but If you can use an encoder instead of a pot, sparkfun hass this...

https://www.sparkfun.com/search/results?term=COM-10596

It has built in Red and Green LEDs, which you can get 3 colors from.  have used it myself in a project in the works, I'm hoping to market sometime this year...



As for mounting LEDs flush with a top surface, I recently had a similar issue. What I decided to do was bring the LEDs flush with the top surrface, and then covering the whole top with a cut out layer of clear PETG plastic. This is a tough plastic, which even in thin sheets like 0.4MM thick, is flexible enough to punch holes for other controls without splitting. Here's an example from another component of that same product.




In this version, I do have one large (5mm) LEd that does protrude to the top, which I later made flush too. Still, next to each stomp button, there is a 3MM red LED, one of which is lit, and all those are already completely under the plastic.

[digi2t]

Pots have a hole in the shaft for the LED, and clear knobs. Get them at Smallbear. http://smallbear-electronics.mybigcommerce.com/clear-shaft-1/



The pots are PCB mount, and the LED mounts into a recess of the hollow shaft.

[steveyraff]

Hey thanks guys,

I'll have a look into this. Thank you all very much for the useful link, I'm going to go check them all out right now!

I am currently building a Dr.Boogie pedal - I was designed some graphics for it today and when I was arranging the knobs, I had this idea to centre the gain knob and also make it the LED so that it lights up red when the pedal is on. If that makes sense?

Also on smallbear is says you can get those clear Alpha Pots with or without bushing. What is bushing? I'm in Ireland/UK so I will try to find a closer supplier.

[italianguy63]

The "bushing" is the threaded part that you would put a nut on when the pot passes through the enclosure.  If you PC mount the pot, and the PCB is affixed somehow inside, you don't need the bushing.  I'd assume you want ones "with bushing."  MC

[steveyraff]

The "bushing" is the threaded part that you would put a nut on when the pot passes through the enclosure.  If you PC mount the pot, and the PCB is affixed somehow inside, you don't need the bushing.  I'd assume you want ones "with bushing."  MC

Yes - with bushing then! Great explanation. Many thanks

[Tony Forestiere]

I like the graphic. No too big of a "Skulls" theme fan, but the colors, fonts and layout work for me. Looks like an easy water-slide print onto a prepped, white enclosure. A bit of clear.

[steveyraff]

I like the graphic. No too big of a "Skulls" theme fan, but the colors, fonts and layout work for me. Looks like an easy water-slide print onto a prepped, white enclosure. A bit of clear.

Yep, I'm always working water slides onto white enclosures so thats what I was keeping in mind. Nope, not a skulls fan either per say - just came to mind for the theme for whatever reason.

Anyway, I'm mainly concerned about how to pull of this pot light idea at the moment - so hopefully the useful info here will help me out!

[amptramp]

If you can find some older surplus stock, concentric controls used to be common.  If you remove the rear control, you have a pot with a hollow shaft that will pipe light right from back to front.  These controls were common on televisions and oscilloscopes.  Some were used in stereo systems so you could have a left/right volume control ganged on one shaft so you did not need a balance control.  Other uses were concentric bass/treble controls on car radios.  Even some guitars had them:

http://www.allparts.com/EP-4585-000-CTS-250K500K-Concentric-Pot_p_1443.html

[steveyraff]

Thanks guys,


I'm having a lot of trouble sourcing clear shafted alpha pots in the UK. Mouser do them, but not 1meg - which is what I need!

Any ideas?

EDIT: Scratch that - I just bought 4 from Smallbear anyway! I got charged $10 for shipping, but hey, it saves me the hassle it was causing looking for some this side of the pond!

[roseblood11]

Tutorial: http://forum.musikding.de/vb/forum/diy-musikding/effektger%C3%A4te/17482-aluminiumdrehknopf-beleuchtung?t=27525&_=1422605710184
You have to be logged in to see the pictures.

[deadastronaut]

@steve:  ive never seen those clear pots in the UK...

[italianguy63]

This is an old post.. but the Duck asked me to post this...  an interesting thing he discovered:

You can used the cheap Tayda knobs, or the cheap Chinese knobs (splined, black plastic with the colored inserts) for this.  If you use a back-lit clear shaft pot, with these knobs, the colored plastic is just translucent enough to let the backlight through!

White and yellow (knobs) are really good.  Others, like green are interesting.

Sorry for the poor picture quality.  But here is a yellow knob with an orange/amber backlit LED:



MC

[duck_arse]

thanks, mark. these:



are the very parts I got from thebay seller "solaluna88"**. the coating is soft-rubbbery, and will need xacto-knifing to remove the flash here and there, and they could use a wash to remove the mould release and the smell. but they are green, pointy, and will be more subtle under-lit than a clear knob.


** I am so not-affiliated w/ this seller that they messed my trimpot order.

[Jdansti]

Mark-do you still have those little boards for lighted knobs, and would they work for this application?

[italianguy63]

Absolutely-- they are exactly for this John-- I sell them on eBay.  But, I give DIY peeps a bigger discount.  You can PM me.

MC

[Jdansti]

Thanks, Mark. I've got some that you generously sent me when I placed an order with you. I was just inquiring for others who might be interested.