The homemade 'green' LED tent light (Design + field test)

Recently I went looking for a small portable tent-light, that can be used during camping and overnight treks. I was targeting the LED's with a heat sink attached to it. I found a variety of such devices but they were not worth the price I was going to pay. Most of the devices used the 3xAAA size batteries which are quite inconvenient to use, especially in India. So I decided to make something much cheap, at home and as I want it to be, in terms of size, shape, circuit complexity etc. 

This time decided to something with the used batteries. Re-generating the wasted energy with the Joule thief ! Hence the name 'Green'. 

Knob on the left side is to control the intensity.
Right side is the switch.
I have used a small wire to complete the circuit

You can see two small PCB's mounted inside.  

Ultra bright LED!!

Once done, I put the setup inside a used plastic shampoo bottle. Used the empty space to keep the spare batteries as well as to maintain the balance of the bottle. In future I will write a blog on my trekking blog- The Mountain Tamers to describe the performance of this device.