proximity sensor reccomendations ?

[[email protected]]

Hello All,

I'm looking for a IR emitter/receiver combo that
could easily be integrated to a microcontroller..

This project involves detecting a presence
of a plastic sheet at a distance 5mm or less.
When the sheet moves and if there are no objects
near 5mm, the signal generated needs to be interfaced
to a motorola microcontroller.

As the plastic sheet surface may not be fully reflective,
will the sensors work for this situation ?
Ambient light should not affect the sensor operation..

Any reccomendations of components are greatly appreciated..

Thanks..
James

 

[CFoley1064]

Subject: proximity sensor reccomendations ?

From: [email protected]
Date: 10/21/2004 4:42 AM Central Daylight Time
Message-id: <1098351991.466735@sj-nntpcache-3>


Hello All,

I'm looking for a IR emitter/receiver combo that
could easily be integrated to a microcontroller..

This project involves detecting a presence
of a plastic sheet at a distance 5mm or less.
When the sheet moves and if there are no objects
near 5mm, the signal generated needs to be interfaced
to a motorola microcontroller.

As the plastic sheet surface may not be fully reflective,
will the sensors work for this situation ?
Ambient light should not affect the sensor operation..

Any reccomendations of components are greatly appreciated..

Thanks..
James

Hi, James. Classic problem here. I'm assuming the plastic isn't transparent.
That adds all types of problems.

If you want an off-the-shelf retro-reflective sensor to interface with a uC
(meaning operates off +5V, has open-collector TTL-compatible output) you could
do worse than the Omron EE-SB5V, available as Digi-Key P/N OR-506-ND. It
operates on 5V, has TTL/CMOS-compatible outputs, and costs $15.78 USD. The IR
signal and receptor are modulated to reject ambient light interference. Go to
Digi-Key, punch in the part number, and examine the data sheet to see if it's
good for your application. The only negatives are that it's somewhat slow (50
Hz max sensing frequency) and kind of small. Of course, if you want to spend
more, there's a wide variety of opto sensors for nearly all applications. If
your budget allows, I'd look at Banner Engineering products.They're reliable
and practically bulletproof. They also have an applications engineering staff
that are very helpful.

I's common, by the way, to affix a reflector to an object to be sensed if it's
transparent or has low reflectivity. Sometimes even a spot of white paint will
do the job. That's something else you may want to consider.

Good luck
Chris