how to focus an infrared light?

Other Hardware Sensors
21

For very-near IR (which is what IR LEDs produce) most standard lens materials will work fine - the focus point will be close to
that for red light. Even a cheap plastic lens and holder should generate a good beam.

For further into the infrared range exotic lens materials are required - salt, germanium, etc.

22

SeanD:
Hi there mjkzz,
If I do get the 3w ir led, wouldn't that fry my arduino?
According to dc42's link:https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcQiEBg44h_5hg9FqHss6SMdKKP7yU7FvG438oU4XvOGS_-sR80D, would I connect uc_out to one of the arduino pin?

This is why I suggested using MOSFET and current limiting resistor to drive it because a 3W ones probably draws 1000mA.

Just a thought

23

Sean,

are you still working on this ?

I use:

  • TSAL6100 IR led for sending from Vishay, it's an IR emitter, does no harm to eyes and such, it's not a laser... lasertag does not use lasers (at least: most do not)
  • TSOP34836 sensors, it's like the radioshack sensor but cheaper; there is a chance it's even the same, but without the metallic housing

You focus the IR beam with any concave lense. Take any magnifying glass, take out the lens, let sunlight fall into the lens and focus the beam on a piece of paper so you can burn a small hole in it. Measure the distance between paper and lens. That will be the distance you want between IR led and lens. You can use any tube construction you like (carton rolls will work as well, though not that sturdy)

Coding wise: Ken Shirriff's IR library for Arduino is a good starting point.

I have a lasertag system running based on Arduino, range ~200 meters confirmed in sunlight. So it is possible.

There are lots of people in the interwebs building lasertaggers, for instance Miles Tag (google). The laserforums provide useful information as well.

Cheers,

Jack

24

this can be a good idea for this?