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I want to create an apparatus (which might be called a paper feeder) to take a still image for each paper taken from a deck of 500 sheets robustly. Robustly means that the apparatus must guarantee all sheets of paper get captured by the still camera.

I am new to LEGO but I think creating the apparatus with LEGO can reduce the cost. I will use for processing more than 2 million pieces of paper.

My questions are

What peripherals are needed to pick exactly one piece of paper (from a deck of 500) for a single camera shot?

In essence I want to replace this scanner job.

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I think only you can answer your second question, since you're the one building it. –  BoltClock Oct 25 '12 at 19:53
Don't current photocopiers do that kind of job easily? If your company doesn't have one handy, you can probably ask for another company to do the job. I think it's a very interesting question, but since it appears to be for a professional environment, I have some doubts as to the feasibility of it with LEGO - at least with the reliability required. –  Joubarc Jan 1 at 10:21
I am also with the same idea... but not with LEGO.. Did you complete the project? If we can discuss it will be good.. –  DeepakJoseLopez Jan 1 at 17:10
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2 Answers

up vote 6 down vote accepted

There are many ways you can approach this problem using LEGO. I would recommend the 8547 Mindstorms NXT 2.0 set, as it includes the software required to program a basic paper feeder including a microprocessor (NXT Brick), three motors, four sensors (ultrasonic, two touch and a colour sensor) as well as plenty of other parts which you can use to construct the paper feed.

Set 8547 also comes with four wheels with rubber tyres which can be powered by the motors to feed paper. These tyres will have more enough traction to pull without damaging the paper.

A colour sensor can be used at a fixed point to detect the start of a new page or a motor can be calibrated to perform an X amount of rotations required to feed one sheet of paper. However if you wish to feed the paper, you need to consider the strengths and weaknesses of the method used as well as when and where it is likely to fail.


You may be able to reduce the costs by purchasing the essential parts from Bricklink. Although it can't be guaranteed that you'll be able to get all the parts in one purchase and it may be more expensive to buy the parts separately.


If you're looking for something reliable that can scan that many sheets of paper, you may find it more economical to have find a professional archival company that can process your documents/images.

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Thank you very very very very much for your answer. It is very useful as the starting point to go. –  Donut E. Knot Oct 27 '12 at 13:33
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Picking paper sheets from a stack shouldn't be too much of an issue with rubber wheels.

However, One of the problems you may encounter is that multiple sheets stick together. To avoid this, you'll first need to shuffle your stack a little (I only know the french word for this process: déramer, sorry.), but even then it can happen.

I've worked with an offset printing machine when I was a student, and the thing had a tendency to pick two sheets instead of one once in a while. There was a mechanism that would discard such sheets, and the way it worked was based on the thickness of a sheet: as the sheet was conveyed on a flat surface, if it was too thick, it triggered a small kind of lever which was finely tuned to rest just above the thickness of one sheet. It was very sensible, too; if there was one sheet it wouldn't budge, but two or more would make it move, and it would activate a trap to receive the offending sheets instead of feeding them to the machine.

To be honest, picking two sheets instead of one was the machine's less problematic behavior, and we were lucky if that's the only thing it did. Which means you'll have to be careful too, so that there is no way for a sheet to be somehow eaten - possibly irrecoverably - by the mechanism.

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