Easy 5 Step Guide to Build a Phone Flashlight

Are you annoyed by the dim light of your phone, is it so dull that it can barely serve its purpose, with the help of this article you can build your very own flashlight for your phone and this is completely beginner friendly, you do not need any prior knowledge on electronic material to understand this article. Just use the links to get hold of the material, follow the steps and you’ll find yourself building a phone flashlight.

Materials needed

OTG cable

Micro voltage regulator


Mouldable rubber

A phone

Hold on! Before you get all excited about building your very own flashlight, take a look at the specs of the phone you will be using, this is to make sure that the phone can support this project, since we will be using an OTG cable. If it does then you can follow the subsequent steps.

Step 1

Take out the recommended USB OTG cable and chop it off, tale the end that will be inserted into the phone and use a wire cutter to expose the wires inside. You can cut off the white and green wires as they will not be needed for the project. You will be left with a black and red wire, solder them so it is easier when using them later.

Step 2

You will need a micro voltage regulator; this is essential as it helps step down the 5v output transferred from the phone. The LED draws too much light and with the help of the step-down board you can regulate this. This is preferred over a resistor as a resistor heats up too fast.

Flip the board and check out the input and output pads underneath. After adding a little bit of solder on them, the wires of the OTG cable can be hooked up on the input side, with black being negative and red being positive.

Step 3

The LED. This is the star of the project. the type of LED you will be needing for this project is a 3 watts unit, use the link provided to get your hands on one. The LED used in this project had a built-in lance, with a heat spreading aluminium base, it also has solder pads and fortunately for you the pads are marked, so all you have to do is attach the wires onto them, with red being positive and black being negative.

The other end of the wires can then be wired to the voltage step down board, pay heed to the polarity of the wires.

Step 4

Your devise is now somewhat ready. When you plug the cable into the phone you will, for just a moment, see the flashlight flicker before dying down. Don’t worry your efforts are not gone to vain, it is not broken, it can be fixed.

This happens when the step-down board is not set up and because of this there is an overflowing amount of power that is being transferred, when the phone senses this it shuts down the power.

To fix this you will have to go through a process of trial and error, by adjusting the micro knob that is present on the board, slowly in an anti-clockwise motion turn the knob. Reinsert the cable into the phone each time until the LED does not flicker flashes of light. Continue turning the knob in an anti-clockwise motion and you will see the brightness gradually increase. When the brightness reaches its peak point the phone will cut down its power, this indicates that you’ve passed 500ma.

When this happens back tract very slowly. Now the devise is set up and make sure that each time you plug it in the phone, the flash should remain long and consistent.

Step 5

You can’t possibly walk around with the way the devise looks right now, this final step is where you’ll be turning your devise into something cute or pleasing to look at. Use some glue to keep it all together, this will make it look like a single unit.

Use some mouldable rubber and wrap it around the devise (make sure you leave out the area when the light flashes and micro knob area just in case you want to adjust it in the future), you can even mould it into different shapes. Once you’ve got the shape that you wanted, smooth out the surface, get rid of any imperfections that can be seen. Now your flashlight is complete and ready to use. Enjoy your bright light.

    Leave a Comment
    Subscribe to our Newslatter

    Sign up for free and be the first to get notified about new posts.