Laser tag update 2/22/15

From last week, I had the following deliverables:

1. Get a larger lens/lenses 2"+ in diameter.
2. Build test set up and test 2" diameter lens (inside and outside) and record transmission distances at standard currents

So, I got a 4.5" lens from an old box of science stuff. I found its focal length by putting it under a light on the ceiling and measuring the height the light was off of the ground when it focused the light on the ground. I then built a (oh so sturdy) cardboard cut out to hold an LED at roughly the focal length away from the lens (I also learned that a hole punch is a little wider than a 5mm LED. I used that to make a hole. This is a test. Quick and dirty is the way to go. Does not need to be exact).

Now for the set up:

Basic Settings
Voltage for LED: 5 V
Resistance for LED: Three (x3) 24 Ohm resistors in parallel, resulting in 8 Ohm total resistance.
Current for LED: .6 (max is 1A)
Lens Diameter: 4.5"
Lens Focal Length: ~9.1"
Max Transmission distance: ??

Secondary components:
Voltage regulator: LM7805C
Transistor: TIP101G.

My goal for this iteration is to build a module that I can run around with and play laser tag with. I need to build a durable version that I can run around with and play laser tag. Then I can start adding things like different lenses, game types, etc.
However, before I build a durable model, I should max out the settings and get tag distances.


1. Change IR LED current to 1 A.
2. Get distance tests for 1 A with 4.5" lens and 1" lens.

Leave a Reply

Your email address will not be published. Required fields are marked *