How do I increase range in IR sensors?

gdim

Is there any way I can increase the distance/range from the transmitter to receiver in IR sensors?· I purchased these sensors which have 8 feet maximum range, but I heard a convex lens can be used to increase it?· What are those, where can I find them, how do I use it and is there another·way I can increase my range without the lenses?

Thanks!

allanlane5

It's not the "sensor" which has the "maximum range" -- it all depends on the transmitter (IR LED), and how many IR-LED's you're using, and how much ambient light is around. 50 or 60 feet should be good -- after all, IR remote hand-helds control televisions and DVD players from across the room all the time.

Andy Lindsay (Parallax)

What's your application and what kind of sensors do you have? (Make sure to include manufacturer and part name/number.)

Beau Schwabe

Andy,

He does link to it, but it's not obvious...
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=177092


IR range can also depend on how well the circuit is tuned.· A simple L-C tank tuned at 40kHz (or whatever) on the
receiving end that is excited by the IR detector can increase your range >>GREATLY<< ...It does look like there might
be a coil, but since this is from a "kit", it probably isn't tuned all that well.







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Beau Schwabe

IC Layout Engineer
Parallax, Inc.

gdim

So, lenses are out of the question?

Mike Green

The problem with lenses is that they narrow your field of view. That delivers more power in a small area, but you have to carefully align the transmitting lens with the receiver and keep it aligned. With IR, you can't see the beam and that makes alignment much harder. You'd really need a converter scope. The other thing is that focal points are not the same for IR. There used to be special markings on professional SLR camera lenses that were usable with IR film. You couldn't use the visible light focus markings.

I'd stay away from lenses other than the ones built into the LED and sensor and concentrate on illuminating the "scene" better with more power (and more LEDs) and tuning up the sensitivity of the sensor.

Keep in mind that most IR remote controls can reliably work across much more than 8 feet without added lenses.

Post Edited (Mike Green) : 9/8/2006 9:09:11 PM GMT