EEVblog® Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: rodrigopires on November 27, 2025, 09:55:51 pm
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I have a very nice USB-C rechargeable flashlight, but the problem is that it has that annoying 3-mode (high, low, strobe), and I only want high mode. The thing is that the flashlight switch is not switching power on or off but giving a signal to the "controller" chip to power the light. The MOSFET (to the right) always has power on the collector, just waiting for the gate signal. How can I bypass/destroy the 3-mode programming chip and still use the same button to power the light?
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You can't. You need to replace the controller IC with your own circuit. A 6 pin microcontroller might do the job, but you'll need one with the power pins in the same place.
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I found with mine that if I shake it, it will turn off without having to click through the other modes. The battery spring allows the shock to momentarily disconnect the circuit and reset it.
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I found with mine that if I shake it, it will turn off without having to click through the other modes. The battery spring allows the shock to momentarily disconnect the circuit and reset it.
add an on-off switch?
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Does the button pull low or pull high? If it pulls high, remove the chip and wire the button to the MOSFET gate. If it pulls low, you'll need to add an inverting circuit, could be as simple as a PNP transistor and two resistors. Or rewire the button to pull high, if that can be easily done.
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You can't. You need to replace the controller IC with your own circuit.
This. I have a few like that and I have a couple that do "High, Low, Flash, S-O-S". What a stupid fucking function. Let's give a child a light that flashes SOS and see what happens.
I've thought about replacing the micro. then I've just decided to not let the kids play with that one.
On/Off would do me fine, but for the $4 the thing costs I can't be arsed replacing the micro.
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This. I have a few like that and I have a couple that do "High, Low, Flash, S-O-S". What a stupid fucking function. Let's give a child a light that flashes SOS and see what happens.
The vast majority of lights seem to come with either lesser braindamage, Low, High, Flash, or greater braindamage, Low, Med, High, Flash, SOS, with a few being Low, Low-med, Med, Med-rare, High, Turbo, Extreme, Slow Flash, Fast Flash, Macarena, SOS, Shave-and-a-Haircut, Beethoven's 7th, Orgasmatron.
I have no idea which genius decided this was a good idea.
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Many years ago, I modded some flashlights to get rid of that annoying strobe mode. In the easier cases, it was sufficient to remove/bypass/mod a capacitor they used to "remember" the last mode while switching off/on.
In the more sophisticated cases, I could usually find a way to bypass the "blinking" IC.
E.g. I has some flashlights using a fake PAM2803 IC which is usually used like this:
[attach=1]
They added a small SOT-23 ("CX2859A") in the circuit to implement the annoying mode selection:
[attach=2]
By bypassing this IC, I could remove the mode switching:
[attach=3]
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These days they may be too "cost optimized" for that. Mine runs on 3 AAA cells and is a single "chip on board" connected to the battery, LED and button.
add an on-off switch?
And annoyingly, it doesn't start by itself after restoration of power.
Full replacement is the only option and it would need to handle both toggling and current regulation, like the original.
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I have a very nice USB-C rechargeable flashlight, but the problem is that it has that annoying 3-mode (high, low, strobe), and I only want high mode.
Many of these torches cycle through the modes when you press the button several times in quick succession; high-low-strobe-off. If you switch on and don't press the button for some time e.g. 30s, the next time you press the button it should just go off. So it is effectively an on-off button, if you leave it on for long enough e.g. >30s. But yeh, other more annoying types exist.
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I wonder if SOS is still a thing in China? I doubt that 95% of the population in the US today would even know what SOS means and I doubt that 99.8% would be able to read a visual or an audio SOS. I don't know about the rest of the world but for the US today, the SOS function in a flashlight is about the most useless function that anyone has ever marketed. At first it appears to be a clever addition to a flashlight but only until you try to to use the flashlight for what it's intended for.
The Chinese (and others) software engineers would be a lot more clever if that included a way to allow the users to permanently turn all of these unwanted features that we getting in all of out electronic products today.
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This. I have a few like that and I have a couple that do "High, Low, Flash, S-O-S". What a stupid fucking function. Let's give a child a light that flashes SOS and see what happens.
The vast majority of lights seem to come with either lesser braindamage, Low, High, Flash, or greater braindamage, Low, Med, High, Flash, SOS, with a few being Low, Low-med, Med, Med-rare, High, Turbo, Extreme, Slow Flash, Fast Flash, Macarena, SOS, Shave-and-a-Haircut, Beethoven's 7th, Orgasmastron.
I have no idea which genius decided this was a good idea.
someone was playing around with software and it ended up being sold, there rest is just people blindly cloning the software and hardware
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Another Mod from 2018:
[attach=1]
And another one:
[attach=2]
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Orgasmastron.
wow up neddy,a torch that plays moterhead? i'll take 2
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There are two satisfying solutions to the problem:
1. Widlerize it (after removing the battery, of course) :-+
2. give it to somebody you don’t like >:D
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Orgasmastron.
wow up neddy,a torch that plays moterhead? i'll take 2
Actually so would I, as long as it had an everything brighter than everyone else mode.
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I just had to repair one of these little sods. Not this one : https://www.evertronics.net.au/products/800-lumen-mini-usb-torch (https://www.evertronics.net.au/products/800-lumen-mini-usb-torch), but pretty much identical.
Most of mine have 14500 cells in them, but the first ones I upgraded have 16340's. They just friction fit in the body past the switch wires, but have a lot of slack space up near the head. My son dropped one on its head and the battery slid up, shearing off the wires from the button and pulling a couple of pads off the control board.
This one I have a bit of an emotional attachment to. Turns out with sufficient patience the head screws off, so I de-soldered the whole lot and managed to get the head off. I could then get a soldering iron down the barrel to re-solder the 4 wires on the switch (B+ / Green Led / Red Led / Button). Once I had that I could bodge up the board and its missing pads, fabricate a foam spacer to ensure it never happened again put the head back on with blue loctite and re-assemble it.
Soldering those wires on the switch I think I understand how a gynecologist feels.
I didn't try and bypass the flasher circuit. Frankly with my shakes these days I struggle to solder a small pad, let alone re-work one of those boards.
I won. Disaster averted and one cheap and nasty Chinese LED torch saved from the bin.
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gynecologist with soldering iron - go away you pictures!