Monday, May 07, 2012

Red light torch (update from earlier project)

So a long time ago I posted a project that loosly described how to take a handfull of red LEDs and put them into a torch.
The idea being that, when you are out at night, if you want to preserve yuor night image then you need as much rodopsin in your eyes as possible, and light bleaches rodopsin, well, most light does, but red light does not.

Which is why you want a red torch to look at stuff when you're out at night as then you can preserve your night vision.

This post is just an update of that project, to show some pictures of the modified torch, and the modified torch in use.

After a while it because clear that this torch was just a bit big and bulky so a new LED torch was made.

Original rechargeable torch from woolworths:

At the start is has a light bulb, which has been replaced with a cluster of LED lights, angled to point towards the reflector:

It's a little more impressive in the dark:

Especially for illuminating star maps when using a telescope at night:

Slimline Torch
After a few months of use it became clear that the old torch was big and bulky, having it in a pocket took up any space that could be being used for keeping sweets or gloves. so a new LED torch was made.

The body of the torch is a white LED torch/cycle light. this is the perfect donor torch because it's largly already setup for use with LEDs.

start with the torch:

you'll need 5 regular brightness LEDs (super bright will take away the point of having a dim red torch to preserve your hight vision:

Take the reflector and lense off of the torch, (this is how you change the batteries)
now using a solding iron remove the white LEDs from the circuit board. -be sure to note their polarity!

Now add the red LEDs to the board, again be sure to note the polarity

Finally test your new torch:

The costs for this project are as follows:

LED torch = £1 it came from poundland, for people overseas poundland is a stock surplus type store where everything inside the store cost just one pound.
5 x LED these are a few pence (because I buy them in quantities of hundreds at a time from Rapid Electronics.

The batteries came inside the torch and so are included in the original pound.

All in all the total price is not more than £1.10

No comments: