Laser Tag Update 2/15/15

So, about two years ago, I wanted to make a course to teach laser tag. I didn't make it a habit, and it didn't get done.

Now, I've made some progress towards that laser tag. However, like the me of the past, this is still a large project, and I haven't gotten very far.

So now, I'm going to (try to) use some of the advice I've got from Extra Credits. They make videos about video games, and their advice can be translated to other projects. I'm specifically talking about their series on making video games, and their rules video. I should refer to this every once in a while when I am unsure of what to do.

Completed Work

1. Create a program to send and receive tags
2. Build a prototype that can send and receive tags
3. Build a lens setup and test adding a lens - adding lens increased tag distance
4. Build LED test setup and increase current - increasing drive current increases tag distance
(Note: requires batteries that can supply the current, and capacitors)

In Progress

1. Increase range of tag unit send/receive


In my meanderings across the internet, books and the like, I have come across information on optics. I haven't done very much with optics, so this is a lot of trial and error on my part. However, I do know that I want to collimate light. Basically, I want to take light from an LED (emanating at about 25 degrees) and turn it into a beam that travels straight. Fortunately, if you buy a lens, they tell you the focal length, or distance away that a collimated light source will be focused. Put a light source that far away, and presto, instant collimated light.

However, what assumptions are they making about that light source? In the land of physics, everything is a point source, meaning it doesn't have any height or width. I tried using a 1" diameter lens to collimate a 5mm diameter IR LED. I got it to transmit about 50 feet, but it did not work very well outside. When I checked what the beam looked like with a red LED, the beam was not a column, but focused a few inches from the lens. If I want my lens to work more like the theoretical column, I need to make my LED look more like a point source. That means a larger lens or a smaller LED. Why not try both?


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

Future work

1. Add more light indication.
2. Make tag unit more sturdy.

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