Full Spectrum Flashlight





Introduction: Full Spectrum Flashlight

I've wanted to build a full spectrum flashlight for a while and seeing the Flashlight Contest advertisement enticed me to build it, asap.  Once I finished this flashlight it turned out a lot better than i had expected.  I now want to make modifications to it to improve it for my next flashlight. I will definitely use this at work now.

Step 1: Obtain Part and Tools


Used or new flashlight casing. I used Military type Flashlight P/N MX-991/U

The following can be found at Radioshack
4.5 vdc power supply (make sure it will fit inside casing with the wires)
     I used a 3v battery holder in series with a 1.5 volt battery holder
     White LED
     Ultraviolet LED
     Infrared LED
     Red LED
     Yellow LED     
     Green LED
     Blue LED
Round PCB (to fit inside flashlight casing and also backside painted silver to help reflect)
     2x 33 Ohm      IR
     100 Ohm         Red
     47 Ohm           Yellow
     68 Ohm           Green
     15 Ohm           Blue
     33 Ohm           UV
     22 Ohm          White
6 Position Switch
22 AWG wire


Soldering Iron
Dremel or Drill
Silver spray paint (not absolutely necessary)
soldering iron

Step 2: Observe Wiring Diagram

Check out wiring diagram so you know what wires go to what component. Since i was only able to find a 6 position switch i had to chose only six colors to use. I chose IR, Red, Green, Blue, UV, and White. I know i'm missing a few colors to make it an absolute full spectrum, but you can add more LED's if you desire.

Step 3: Start Building

Solder connections carefully. make sure all points have contacts where there supposed to have them, you should also be sure to think out how its going to be put together. for example when i put mine together i realized that i had to put the lights on one end of the flashlight casing then feed the cables through and solder the other end on at the other side. Also be sure to solder the LED's in their proper direction or they will not work. another thing i did was use the existing switch on the flashlight and separated the ground by it, so that i could control its on/off function with it.

Step 4: Assemble and Test

Piece together you flashlight and see what you've got. Here are my colors; IR is invisible to the human eye but visible with a camera, Red, Green, Blue, Ultraviolet, and White.

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    I often thought about converting my tactical flashlight to LEDs. The damn things eat batteries, and then not only you have to pay for the batteries, you also have to carry spares batteries and bulbs! I'd definitely convert one to work with white LEDS if I hadn't lost mine and eventually needed to buy a new one. The full spectrum would have no use for me. Adding a switch on the outside would make it inherently less reliable (there's one more element that can fail) and I'd still get all the colours I needed using filters. If you'd do a "tactical flashlight that won't make you carry a pound of extra batteries" instructable, I'd give it a 10, just like that.

    3 replies

    hello, if you not yet buy a flashlight with leds there its available military angle head flashlights with 5 led head from the companies mil-spec and mil-tec, and they are cheap too. and you can also use the color lences too!. i buy 2 mil-tec ones one with D cell batteries and one with C size batteries.

    I also use a tactical flash light ( a right angle torch) with lenses and as good as it is the only problem with it is it is awkward to change the lenses in the dark without loosing any and the lenses also dim the light.

    Good suggestion! I'll keep that in mind for the modification update for this mod. I've got some other ideas to improve this as well that you may like.

    that round board you used...
    THAT can be bought at Radio shack?? and it does not have to be cut down?
    I have a 2 cell(3 volt) flashlight that I want to convert to LED, & with that round board, I can see me using that + about 18 - 20 LEDs... :)

    TY for sharing Sir.

    You can try adding near IR, deep red, red, red-orange, amber, yellow, green, cyan, blue, royal-blue, violet, near UV, and white. The CRI should be as good as using a halogen lamp.

    I'm doing a similar project, but I'm trying to give each color its own potentiometer so that there's an infinite number of color possibilities.

    So, I'm guessing that this doesn't give off radio waves, microwaves, x-rays, and gamma rays! Boy, what a cool invention that would be...

    2 replies

    LOL, instant superhero: just set to gamma rays, point, and click!

    more like instant cancer!

    Could you be more descriptive about how to go about soldering/wiring this? Also, how do you control which LED is on?

    1 reply

    yes, as soon as I get time (within a week or two) I plan on improving this instructable with a better wiring diagram and more descriptive instructions on how to build it. The six position switch on the bottom of the flashlight controls the current flow through the appropriate resistor connected to the appropriate diode. On the center pin of the switch is the ground wire which is connected to all the diodes grounds (cathodes) through the on off switch built into the flashlight. When you turn the six position switch you control which diode lights up.

    You don't need any more led's too achieve a full (visible) colour spectrum, in fact you don't even need the yellow and white. Contrary to what Sharp would want you to believe you can generate the entire visible spectrum using just red, green, and blue. You would just need to create a better way of controlling it as you would need to mix different values of each of the leds/led (you can get RGB leds) Though you could go with adding all the colours between and extend it just through simple blending like this. Overall nice instructable, I might have to build my own full spectrum flashlight now. It would be nice to have a high brightness one for photography (though it would have to be very bright >_>)

    4 replies

    Hi, someone already made a RGB flashlight, including mixing colours and brightness control: http://www.youtube.com/watch?v=s4nZe5M_kyA RGBW led is driven by microcontroler driver, modes are being changed using only a single on/off tail switch ;)

    That would be quite hard to be able to control how much of each color you get, but it is possible.

    Well a simple way would be to have one potentiometer for each led, so you can manually control the colour, and it would allow for added mixing like, UV+red+green or IR+UV.

    Still not an easy way to control it.

    This'll be great for watching the Persied meteor shower! I won't lose my nightvision looking at the star chart or finding my way back to the car!