Saturday, October 18, 2025

The Red Light Therapy Light

Tonight on "why did this not work?" A red light thingamajig:

 
The issue: not maek light.Oughta should. The display comes on, but no light, red. IR, or otherwise.


So..... The AC adapter seems of good repute according to the sticker. FCC and proper CE listed. CUI Japan makes good power supplies according to easy research. The red accented sticker on the back of the unit seems confused though. You don't list the input voltage of your wall wart on the unit. You list the voltage the unit needs.... If you plonked 85-265v of any flavor into this thing it's let all the smoke out in dramatic fashion.

 
It's hard to read, but the electrolytic cap next to the input plug is 36v rated, not what you'd expect of a 12v rated device normally....


The 24v rated fan also points toward the 12vdc wall wart that came with this light being weird/wrong. It doesn't spin on it's on at 12v, but the most gentle spin makes it turn gently.

Traced down one stretch of the board. White solder mask on an aluminum substrate board is good design for a light, but annoying to reverse engineer. Blue sharpie shows it as 12 single LEDs in series, or 2.0VDC drop at 24v input. popping an 2032 cell across each LED confirmed they all worked fine. 3v may or may not be a little hot for non-blue/white LEDs, so don't cook em long.


Finished out that section, and it's a little odd. 10 LEDs, sharing the head and tail of a couple of the string of 12 LEDs on the top half. 2.4v is still fine, just an odd design. Either way, onward with the suspected 24v expected input.

Dug around the Bucket-o-AC-Adapters, and by God a 24v plug is just what the doctor ordered.

If you turn off the visible red LEDs the IR ones light with the typical "barely glowing to the eye/FIERCELY INTENSE to the camera" kinda blast.

Why did this device ship with a 12v adapter on a 24v device? The world may never know. But it blasts hella bright red blind spots to anyone interedsted.

Tuesday, June 17, 2025

Taming the wild LED bulb

A few years back BigClive did a great run of videos on the now ubiquitous Normal LED Bulb, how they're driven, how they're usually overdriven to make them die faster, and how to chill them out by replacing their current limiting resistors.
https://www.youtube.com/watch?v=5HTa2jVi_rc
I tried my hand at such a mod today, grabbing the first bulbs in my stash that looked about right.


Can you guess which I've already messed with? Anyway, the long and short of it is to clip or rip off the original surface mount current-setting resistors and plonk on a 220 ohm resistor to the same points, and it gives you a light that'll last for many many more years than it originally would, and divides the original output by 1/10 or so for most bulbs.


The unmodified bulb, original resistors by R4 and R3.

Modded with a 220 ohm resistor. The spring clip is common with the now empty right resistor pads.

 
The camera really mutes the difference between the two, but subjectively the one on left is about 1/4 or less bright than the one on right. The reflection on the ceiling tile/metal is a decent indication of the difference.


Now the kitchen can be minimally lit anytime.

The Red Light Therapy Light

Tonight on "why did this not work?" A red light thingamajig:   The issue: not maek light.Oughta should. The display comes on, but ...