Need Help Alligning IR lasers

[berry_bryan]

Greetings,

I am currently developing a product that uses two alligned Infrared laser diodes for data collection.  Unfortunately, as you all know, I can't "see" the IR beams and so have an incredibly difficult time focusing the side-by-side diodes on the same area, which is essential for proper data collection.  Does anyone have any ideas that could help? Is there an inexpensive way to "see" IR lasers?  Any help would be much appreciated. 

[audioguru]

A video camera sees IR. Technicians use a plate of something that glows with IR.

[berry_bryan]

I thought about that - I wonder if I could use my home video camera (which has a night sight mode) to see the IR spots on a surface... I wonder what surface I could use?  Thanks for the reply!

[STEVE]

You could also introduce a small circuit which indicates when the IR beam passes over the photodetector.  Circuit consisting of an Op Amp and an LED (visible one!) for the output.

Attach the input of the Op Amp across the photodetector, turn the IR diodes on, try directing the IR diode towards the photodetector.  The visible LED will light when IR beam hits photodetector.

Probably a bit more complicated than just using your camera but still another way of doing it!

[awright]

Video cameras inherently have near IR sensitivity but optical filters are added to suppress the IR sensitivity.  I have heard of some people advising that you can remove the filter, but don't know if that is true.

IR sensitive screens are available from some optical component suppliers.  I think that Radio Shack sold such a screen at one time.  Check their catalog.  It looks like a slightly yellow piece of white plastic "paper" and after activation, it glows where the IR beam strikes it.  I know nothing about its sensitivity, but I think it is recommended for aligning IR sources (near field only).

Check out Thor Labs, Inc. ITEM # IRC3,5, or 7 at $110 each.  They have 1.5" x 0.75" sensitive areas on 2.25" x 1.5" cards.  The catalog blurb says, "...providing the user with an instant visible pattern for determining beam location and beam size."  IRC3 is sensitive from 700 to 1400 nm.  IRC5 is sensitive from 800 to 1700 nm.  IRC7 is sensitive from 700 to 1600 nm.  www.thorlabs.com.

You can buy IR viewers for a few hundred dollars.  Check out Edmund Optics at www.edmundoptics.com.

Have fun.

[ante]

Hi berry,

I made an experiment with my cellphone camera and my TV-remote, the IR is clearly seen (flashing) in the almost dark room! :D

[awright]

Neat, Ante.

awright

[Shahriar]

I have not done this, but think about it....

Use a laser Pointer (Those use in Conferences) and fasten the pointer to the IR Tx. then Once you adjusted RX and TX when they are close to each other, then Mark the Laser pointer Somewhere on receiver. In this way you can adjust them in far distances...

I hope I could write what I meant... ???

HTH - Shahriar

[steven]

look in the forums, somewhere i posted key chain laser power supply, the receaver circuit for it is allso an infrared activated switch, or relay circuit it has an led that goes out when the laser is lined up with the photo transister