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Photoelectric Sensor with linear spread

Photoelectric Sensor with linear spread

Photoelectric Sensor with linear spread

I am looking for a simple photoelectric sensor/switch that detects over a line not a spot.  It will be used to scan in between conveyor rollers and I need a scan length of 6-15".  I don't want to go the light curtain route.  Are these common?  Any brands or I should I be looking into a different type of sensor?  For some reason I can't find any.

RE: Photoelectric Sensor with linear spread

what are you trying to sense on the conveyor?
Large size?
reflective material?
how fast the the conveyor moving? and what is the end goal of the sensor?

StrykerTECH Engineering Staff
Milwaukee, WI

RE: Photoelectric Sensor with linear spread

The brand name that comes to mind is Banner.  No affiliation.
There are others.
Just get the catalogs and start reading; there has to be something appropriate.

You might search on 'line scan camera'.


Mike Halloran
Pembroke Pines, FL, USA

RE: Photoelectric Sensor with linear spread

It will be sensing clear flat glass.  I am setting up zones across the width of the conveyor and the glass could be 5-24" square.  I just need a simple normally open sensor/switch.  I use photoelectric sensors now in a diffuse configuration and they work well to see the glass.  The only problem is the sensing area is ~ a 1/2" spot.  I need it to be more like a line.  I've browsed through Banner, Sick and Omron, couldn't easily find what I was looking for.  I'm not entirely sure if sensors with this sensing area exist.  I would like to keep the diffuse configuration(one sensor that is the transmitter and receiver.)

RE: Photoelectric Sensor with linear spread

Getting it focused and aligned will be tricky, but try interposing a cylinder lens between the sensor and the object sensing area.  That should turn the active area into a long ellipse.


Mike Halloran
Pembroke Pines, FL, USA

RE: Photoelectric Sensor with linear spread

Sick also has a red LED array sensor called the WL27 that is a line instead of a spot, but not 15", more like 2". You could use multiples, I believe they can be set up to not have gaps. Couldn't you look at the side instead of down? That's how it's usually done (I just did a similar project for solar glass).

Click picture for video.

There are also inexpensive forms of light curtains for such applications, as opposed to the ones used for safety. As sensors, the beams are more spread out and the safety functionality being removed makes them a lot more affordable for things like this.

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RE: Photoelectric Sensor with linear spread

Thanks jraef,
Unfortunately I cannot look at the side as I need to split the conveyor into 3 zones and that would only do 1.  Also I must use diffuse as I cannot have anything below the conveyor, this pretty much voids non-safety light curatins.  
I think what I will do is just chain together a bunch of photoelectric sensors and create my own array.  It seems Automationdirect sells some for ~$40 or so and that is cheap enough.

Thanks everyone.


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