Alembic Guitars Club
Connecting => Miscellaneous => Topic started by: BeenDown139 on February 05, 2022, 10:35:02 AM
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A public service DIY hack presented by the local electrical engineering curmudgeon
i now have 3 basses that have a FretFx LED strip on them. While i think the concept of this product is extremely clever, it does have a glaring (pardon the pun) deficiency in that the LEDs are very, very bright - way too bright if you play in a dark room and all you need is something to guide your fretting hand without lighting up your face from the bottom making you look like something that just crawled out of the crypt.
so last night i had one of those spontaneous brain emissions that i'm prone to from time to time, usually brought on by a therapeutic dose of the lovely colorado high-potency weed that our fine state so proudly features.
i made up a lamination that sits on one surface (doesn't matter which one) of the watch battery that powers the LED strip with the battery surface the bottom layer, a 500-ohm resistor lead the second, a piece of metallized duct tape to stick it to the battery third, a piece of electrical tape for insulation and a piece of AWG 26 wire held down with another piece of metallized tape as the top layer that contacts the battery holder. This effectively puts a 500-ohm resistor in series with the LED strip. The adhesive on the metallized tape is aggressive enough to hold everything in place. The compressive spring tension in the battery holder keeps everything squished together and a little dollop of hot melt over everything keeps it all together so you can just remove the whole assembly like you would before the modification to turn it off. It’s not pretty, but it does what it’s designed to do. One of my design goals was no modification of the FretFx strip itself. I can think of a couple of ways that I could fabricate a thin PC sandwich that you could slip between the battery and one of the contacts in the battery holder. This is more or less a proof of concept exercise. BTW my first plan was to solder the leads to the battery, but it’s made of a metal that won’t solder, probably stainless steel.
The pre-mod current was 7.5 mA through the LED strip, adding the resistor in series dropped it to 1.2 mA and made LEDs much more subdued. I could probably drop this to 500 uA and still get plenty of light out of the LEDs. Alas, I can’t just nip over to the local radio shack for a handful of over-priced crappy electronic components like I could back in the days of my youth, so I had to use what I had laying around from another project. The pre-modification green LED strip was so bright with a fresh battery that it was almost blinding.
The batteries last so long in one of these, it takes forever to get one discharged to the point that the LEDs are not overpowering. I had one battery last almost 9 months of steady daily use, which I find remarkable. If you need full intensity, you can always put in a fresh battery.
Now on to the one-button switchover box to convert my bass rig to stereo for the Series I, mono for the rest of the crew…
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I tone down the brightness of my FRET fX LEDs by using a 2032 battery that has been drained from using it in my clip-on tuner.
Bill, tgo