Hyperspectral Flashlight



About: I am an eight grade student and I just love making cool (sometimes maybe even useful) devices.

I made a compact, powerful and versatile flashlight which has both UV and IR light in addition to the white light. The white light has a power of 6W and should have a lumious flux of around 560lm. It's equivalent to a 20W LED light or to a 100W halogen light (it's very bright). It can be used as a normal flashlight. It's also very useful for photography and filmmaking. I use it all the time. It's really a very versatile tool. The IR light can be used for night vision. And the UV light? That's just awesome. It can be used for checking money validity or at a party.

I found similar projects on the internet (such as this one) that are really nice but they don't deliver as much power as mine. This device cost me about 30€ but you can reduce this to 20€ if you get the li-ion batteries from old notebook.


Some technical details:

white light intensity and power = 560lm, 6W

UV light intensity and power = 80lm, 6W

IR light intensity and power = 50lm, 6W

weight = 300g

size = 10x5x9 cm

battery life = 2 hours

charging time = 2 hours


Note: This is a reupload of my previous instructable. I needed to delete the original instuctable because of some private reasons. But it's back and there have been some improvements.

Step 1: Parts List

For this project, you'll need following components:

2x 3W cool white LED with PCB

2x 3W UV 395-400nm LED with PCB

2x 3W IR 850nm LED with PCB

2x samsung 18650 2600 mAh li-ion battery

3x constant current regulator board

1x 18650 parallel battery holder

1x li-ion battery charger module

3x black 12mm push button switch

UV protection glasses (optional but recommended)

1x charging connector (I used DC barrel but nearly any other connector would work as well)

200x280x3mm (8"x11"x1/8") black acrylic panel

1mm thick aluminium panel

couple of wires

some M4 nuts and bolts

screw terminal

Estimated project cost: 30€/35$

Step 2: Tools

These tools could come in handy:

laser cutter

wire stripper

soldering iron



glue gun



Step 3: Safety

The danger of UV radiation is a big concern for many people. It is hard to tell whether my flashlight is safe or not because it is still a theme of ongoing research. 80 lumen UV light source is very bright, but the wavelength is 400 nm, which can be barely considered UV. But even violet light can be harmful. One thing's for sure: you will be fine if you won't look directly into the light source and if you won't use the flashlight for very long. But in case you want to use it for longer periods of time, you should consider buying UV protection glasses, such as these.

Step 4: Cutting the Case

You'll need to use a laser cutter to make the case. I used GCC SLS 80. If you don't have acces to a laser cutter (as me) there are many local services (I cut my case at Lab.cafe), that you can give these vector graphics to, and they will cut it to you for affordable price. All needed files are included in this step.

Note: This case was drawn for 3mm (1/8") thick material. Make sure that you have this thickness.

Step 5: Cutting Aluminium

The whole case of this project is made from acrylic but this panel that holds the LEDs in place is from aluminium. That way it acts as a heatsink and the LEDs will not overheat. I have very small experience with cutting aluminium. My friend did cut this part for me so I can only point this instructable out to you. Anyway, the dimensions for the panel are 92x72mm. The holes are 4mm wide. You can use the files from the previous step as a template for cutting.

Step 6: Making LED Array

You need to have a LED array that holds all of the LEDs in right place. We start by soldering white LEDs in parallel, UV LEDs in parallel and IR LEDs in series. Then, we place all LEDs into their pre made laser cut holes. After that, we spread thermal paste all over the back side of the LEDs. Then we can add the aluminium panel that holds all of the LEDs and screw it in place. You'll get kind of a LED sandwich. Then we add a screw terminal on the back of the array in order to have the connections more organised.

The white LEDs and the UV LEDs should be connected in parralel because they work on 4V and the li-ion batteries are at the same voltage level when charged. The IR LEDs should be connected in series because they run on just 1.6V, so 4V from li-ion batteries would damage them.

Step 7: Making Switch Array

Okay, so now we have the LED array so it's the time to make the switch array. Just screw tightly all switches to the acrylic panel and soler wires to them according to the wiring diagram. These switches will be used later to turn on and of the individual LED sections.

Step 8: Power

Because this flashlight draws around 1.5A we need pretty strong batteries to handle this current. I decided to use two 18650 3.7 2600 mAh li-ion batteries. They're heavier and bigger than li-po batteries but they're cheaper and they fit in the case too. The device should work for about 2 hours and it should be charged for about 2 and half hours when using 5V 2A charger. You'll need to make a battery pack. The best option is to use battery spot welder but since they're pretty expensive I decided to just glue two 18650 battery holders together and connect them in parallel. I used 5.5/2.1mm DC barrel as charging connector but you can use any other connector that you like. Just keep in mind that the adapter that you will be plugging into this connector has to have 5V 2A output.

Step 9: Putting Everything Together

Just glue all of the acrylic panels together. I used a hot glue gun to do this. Also, connect all the electronics according to the included scheme. The constant-current module is important for reducing overheating of the LEDs. If everything is working correctly, you can glue the last panel and close the case.

Step 10: We're Done

So, there you have it, a versatile, portable, 18W hyperspectral flashlight. I hope that you like this instructable and that you think that it is useful. If you have any questions, notes or suggestions, please let me know in the comment section below.

If you like this instructable, please vote for it in the Make it Glow Contest. Thank you!



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