Blue LED Flashlight Mod




Here's a quick 10 minute hack to turn an ordinary white LED flashlight into a much cooler blue LED one.

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Step 1: Dismantle the LED Part of the Flashlight

Take appart the top part of the flashlight, and remove the LEDs from the reflector part.
This may be hard, as it's stuck in there, but in the 2 that i've done this two, they aren't glued at all, so it should be easy.

Step 2: Remove the Old LEDs

Desolder the old LEDs from the round PCB, be sure to mark the direction of the flat side, as that's important.

Step 3: Put the Blue LEDs In

Put the Blue LEDs into the holes you just made. Be sure to keep the flat side pointing in the same direction, otherwise the circuit wont work.

side note, ultra bright white LEDs use the same current as ultra bright blue LEDs, green ones will also work, as should violet, and pink LEDs.
Red or yellow will not work.

Step 4: Put the Flashlight Back Together

That's it 3 and a half steps, super simple, and even though the blue LEDs are no where near as bright as the original white ones, the simple fact that they are blue makes up for it!

see some more pictures heresee some more pictures here

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    28 Discussions


    9 years ago on Introduction

    I read your instructable some time ago, but never really had a reason to switch out LED's in a flashlight other than just for fun. Recently though, I had the need for a portable and bright UV light source. I found two Guidesman flashlights, each under $10, at a local Menards and went to work. Thanks to the inspiration from your instructable I was able to convert both flashlights, one with 9 LED's and the other with 15, with relative ease. I don't know if I would of thought to do this myself, so I wanted to give you my thanks.

    4 replies

    no problem that's why i made it!
    I do have a question, how is the UV leds?
    Because I was recently looking to get a UV light for some stuff, and I'd much rather make my own if possible.

    what do you mean by defuse?

    like diffuse the light so it's not a point, encasing it in clear hot glue is somewhat usefull for diffusing it.

    i'm not sure what you mean by defuse though.

    I was more than happy with the ones I bought from . If you need the tech specs of the LED's look to the comments on that same page. If I have my flashlights on for a while, they get pretty warm though, but they are bright and that's exactly what I wanted.


    9 years ago on Step 4

    you could buy brighter blue LEDs that are made by the same manufacturer of the flashlight from, since I've only frys sells them. And of the three stores ive been to (all in one day lol) I've only found red. I think coast uses cree LEDs and brands them as their own.


    9 years ago on Step 3

    why don't you just color the LED lightbulb blue with a sharpie or something

    1 reply

    Reply 9 years ago on Step 3

    because you'll just let the blue light out, and the rest (white is a mixture of all colours, after all), and the rest will turn to heat. Blue LED's just turn most of the available electricity into blue light, so are more efficient.


    Reply 10 years ago on Introduction

    Accidently replied to Frogz instead lol You can make it "black" (as in ultra-violet) but not really black. This is because darkness is just the absence of light.

    Deadly Computerk300000

    Reply 11 years ago on Introduction

    it will work with red or yellow, but the voltages are different. the blue LEDs i used were the same voltage as the white ones. If you used red or yellow you would have to have more LEDs or a resistor of some sorts because they use less volts then the blue ones. i also used blue because, i like the color blue better


    Reply 10 years ago on Introduction

    Consult For a primer.
    Note though, that it is not exact.
    The blue led I ripped out of my broken external harddrive won't even dimly glow till AT LEAST 3.5 volts are applied. 3.7 volt Li-ion battery gives it 'just enough' power to run at 'normal' brightness. SOME leds, have resistors integrated, for 5 volt, or 12 volt applications. I even have one BRIGHT blue led, pulled from a toasted external harddrive, that requires 4.3 volt just to light, and begins getting 'warm' at 5.2 volt.As far as i can tell, that one has no resistor in it.... but it may be really tiny, and hiding in the plastic lens body so infer what you will from that.

    The problem with using lower voltage leds, with a higher supply voltage, is you are over driving them. they may light up nice and bright for a time, but then will burn themselves out from the thermal overload.


    10 years ago on Introduction

    a red mode would go along way. if im not mistaken , at night red is better on the eyes. helps with your night astronomy software on my laptop is lit up in red for night..


    wwell atleast we know that your not color blind LOL. (it's blue) ah no offence saw an oppertunity and took it dude! \