Homemade Flashlight, Part II

Now for the making of the flashlight. I needed to find a few elements, but the ITP shop has a lot of hidden gems. I found this little guy in the junk bin. Who knows what it did, but it had the perfect little ON/OFF switch I was looking for.

Something with an ON/OFF switch

Knowing that I had a working flashlight with 2 double A batteries made me at least confident that I can at least replicate the functionality of this object.

Using a free LED from one of the shop bins, I started to see if I could build out the DC circuit to the batteries. Really I just wanted to see if it worked and if I could get through this exercise without using a soldering iron.

This LED turned out to be not very bright… but at least all the pieces worked together.

Still sticking with the plan to use a bottle as the housing, I developed a simple design for a bottle flashlight with an ON/OFF switch in the cap. The cap can also act as a mechanism by which the batteries can be removed. 

With the design more or less finalized, I worked on building out the cap mechanism. I pulled out the switch from the piece of junk and realized that I would need to fasten it to an intermediary material because the screw holes were facing the wrong way. I found a piece of plywood that I cut, sanded down and drilled some small holes that would fit the screws of the switch.


Using wood as an intermediary meant that I wouldn’t be relying on glue to fasten it to the plastic cap I was using, I could screw it right in. I drilled a few holes in the cap and put it all together.

After adding the batteries, I was able to create essentially the bare minimums required to call something a flashlight.

Final steps remaining are:

  • Make sure this fits in a bottle.
  • Switch out the light for something a little more serious.
  • Figure out a way to squeeze in a material that could make a good focusing chamber.

See other related flashlight posts here.


  1. Nice work.
    Good idea using the cap to connect to the bottle. And good use of scrap from the junk shelf.
    I’d like to see a image or two of the flashlight fully assembled with the bottle.

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