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Hi I want to make a label counter, I got this label rolls that look like this

I would like to move 500 labels at a time, from the big 3000 labels roll to a smaller one with 500 labels.
How can I count this type of label roll, I was thinking about a sensor of some kind.
Does any body know what kind of sensor that can do that, and with arduino  smiley-lol


I appreciate all answers  smiley-lol
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From the picture it looks like the roll material is more transparent than the labels, so an optical sensor could do the job. What speed do you expect when unwinding the roll?
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I was hopping for maybe 50 labels pr second, but off course, I don't want it to begin smoking or burn  smiley-lol
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- measure reflectiveness. Labels reflect more light
- measurement distance, small wheel with rotation counting
- measure the time you power the motor (how exact should it be 500? is +-1 acceptable?)
- measure the weight of the roll left
- measure diameter of roll left (difficult one)
...
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Rob Tillaart

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Hi robtillaart
When "Labels reflect more light" that's nice you pointing that out, then I could have a sensor only on one side, that transmit and receive, and when there is a drop in the light, that is being reflected, I know that's a gap between labels, ->one label
the speed is not important, the bigger the roll is getting, the faster the speed, so I was thinking about using a electric motor, that have fixed RPM.
I will put a electric motor, that's rotate on the side there is pulling, but I need some sort of resistance, on the other side, so the tape will be stretched.

will a QRE1113 Line Sensor do the job, or QRD1114 Optical Detector / Phototransistor
https://www.sparkfun.com/products/9454
https://www.sparkfun.com/products/246

or is there a better solution ??
I don't know alot about sensors, and the specs, on the sensors says nothing about refresh rate ??
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Quote
then I could have a sensor only on one side,
Yes, I wrote that in my original reply too but removed it smiley

Quote
or is there a better solution ??
(this always depends on the definition of the word better)
Don't know, if it is works, it is good enough I would say 
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Rob Tillaart

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will a QRE1113 Line Sensor do the job, or QRD1114 Optical Detector / Phototransistor

These sensors are made for a distinction of black and white. I'd guess that the difference in reflectance between the label and the carrier material isn't big enough for these sensors. You might have to choose a sensor where you can adjust the threshold level between object and not object states.
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I made some tests with QRE1113 sensors and I do not think that this will work for your requirements. You can try to use the sensor as analog device but the initial design goal was a kinde on / off switch.

If the backing film is more or less transparent you may try a fork light barrier. Even when a standard version is not working you can try to use a really bright LED on one side of the label rolls and an normal light sensor on the other side.

There are also Sharp distance sensors out that are designed to detect if a sheet of paper is feed in. They measure the thickness of a paper. This is also what you need. but I think 50 per second is really fast, and the fast moving process will also cause a jitter of the roll. You may try this one http://www.produktinfo.conrad.com/datenblaetter/175000-199999/185366-da-01-de-PRAEZISIONSSENSOR_GP2Y0AH01K0F.pdf 4.5 - 6 mm (0.1 mm resolution) but search it there is one out with a higher resolution that I oversaw.
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I built a counter for labels with a fork sensor. Worked pretty well with around 20 labels per second. Of course it depends on the material and the used sensor. But I guess a standard one will do the job.
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