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IR Reflections

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Musicmanager

Active Member
Hi Guys

A bit of maybe useful info .. .. .. .. .

I've a project on the go at the moment that includes collecting a signal generated from an IR LED and a photodiode which are 'looking' at a large nylon sprocket.
I milled some slots in the sprocket just wide enough to house a suitable strip of reflective tape, however, I discovered that centrifugal force kept loosening the tape until it disappeared.

I tried various 'standards' of white gloss paint and whilst they reflect IR some of the time they are affected significantly by ambient light.

I've found some paint known as 'Starglow', actually intended for UV reflection, that copes very nicely with IR and of course, stays put. It is also unaffected by ambient light.

www.glowtec.co.uk will tell you all you need to know

S
 

jpanhalt

Well-Known Member
Most Helpful Member
Hi MM,

I think for that application the most effective solution will be a modulated IR beam and a matching receiver like this: http://www.vishay.com/docs/82463/tsop62.pdf

I believe it can be done with 555 technology for the modulated beam, but I used a simple PIC MCU. You will probably not need any reflecting tape

John

Edit: Just realized I simulated it several years ago:
If you have interest in that approach, I might actually have built the 555 version and can try to hunt it down.
 

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Musicmanager

Active Member
Hi John

Good to hear from you .. .. .

Although not that actual component, I did try for some time with a similar version driven by a 555.
The problem is the nylon sprocket, even with the minimum clearance, is 20mm wide and at that range the results are very temperamental.

I've solved the issue using a HOA1405 with reflective paint in the slots, it works a treat, very stable and not affected by any ambient light issues.

Thanks for your help .. .. .

S
 
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