Picture of Joule thief bicycle light (front)
Transform cheap bicycle light into Joule thief bicycle light
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Step 1: Introduction

Picture of introduction
I want to apologize for my poor English, but i will give my best to explain and include a lot of pictures for the illustration

First of all, Im not going to explain how j.t. circuit works, or how to make one, for those information you have to look for other sources.
I will explain how to use j.t. circuit with bicycle light and convert it to efficient and relatively cheap source of light.
Ive bought cheapest bicycle light for this project (1 euro) and a small lever switch.

Step 2:

Picture of
First you need small ph screwdriver to disassemble board with leds and electronic switch (circuit).
Electronic switch cant be used with 1,5 volts or less so we are going to dismiss it and use small lever switch which will make whole project little more bulky than original one but that’s the price of transferring from 4 AAA cells to only 1 AAA cell.
Take out leds with soldering iron.

Step 3:

Picture of
Take out battery terminals , cut one in a half (because we will use only one cell, which one to cut you can see in the pictures), than we need to flatten one side of the battery holder to make place for j.t circuit. ( cut out the plastic which is dividing the battery compartments). Its important to flatten it as much as we can to make enough place for the board. You can use sharp knife, scalpel, sandpaper or dremel with sanding stones, as you can see in pictures i like to use small chisel which ive made from an old screwdriver and piece of sandpaper for finishing. Use coarse sandpaper because glue will hold better for the rough surface.
brankomaster (author) 2 years ago
If you think about original version (new) it had three modes

full brightness
half brightness
brankomaster (author) 2 years ago
No it doesn't, on and off only.
I was thinking about that too, something like this


but than it will always blink, for me its better to continually shine.
does this light have a blinking mode?
brankomaster (author) 2 years ago
Here is the link for instructions how to make Joule thief bicycle light (back)