I built "Auto page flip Scanner"

[cday]

Does anyone know how the platen box is programmed to stop at exactly the book gutter?

Presumably the vertical position of the book gutter will vary depending on the thickness of the book, and probably how far through the book has been reached? A mechanical microswitch might be one easy, readily available and inexpensive solution?

If the gutter position does not in fact vary, a microswitch would certainly a good starting point.

There are also, I think, photo-optical sensors that might provide a non-contact solution, some research needed there, but this is one that can be used as a limit switch might be usable, the limit distance would probably vary with the paper reflectivity, but that probably shouldn't be a serious issue. Another type might use a light source emitting at an angle and a light detector also set at an angle.

Are there no clues from close examination of the video? Probably little chance of a Japanese speaker reading the thread in the near future, but you could always try contacting Moose...

[bokks]

Thanks cday for providing some options. I will investigate these. Since the gutter position varies, some sort of pressure sensors might be a good option. But I was thinking on where to place it? do you have any suggestions?

Also i did try contacting moose, but received no response from him. It looks like he is not active in this forum for quite some time. I have got the files which he shared earlier, attaching it along side so that if you or anyone else knows arduino code can go through it and provide some information.

[Konos93a]

https://twitter.com/AlexReibman/status/ ... kGimAOryeA

i will try to communicate with these people to have some results for bigger books

[cday]

Thanks cday for providing some options. I will investigate these. Since the gutter position varies, some sort of pressure sensors might be a good option. But I was thinking on where to place it? do you have any suggestions?

You are right, I think, that using either of the types of sensor identified above comes up against the problem of where they could be placed without compromising the basic operation of the scanner!

Two other at least theoretical possible ways of determining when the platen is in contact with the book being scanning could be to monitor the motor drive current which would be likely to increase when the motor is stalled, or to detect the end of platen travel by monitoring the rotation of some part of the travel mechanism which would cease rotating, that could in principle be detected electronically using some kind of sensor.

But trying to deduce more information from the videos and drawings would seem best initially.

Edit:

I've taken a look at two of the files bokks posted above, the 'Controller block diagram' and the Arduino code in the file with an ino extension, which can be viewed in a text editor if the extension is changed to txt.

The block diagram shows a photo interrupter apparently located below the book cradle, which I suspect may be the sensor used to halt downward travel of the platen. That possibly implies that there is no direct adjustment as the gutter height varies, which might conceivably be satisfactory if the platen is lowered gently with, if necessary, part of the weight counterbalanced?

That hypothesis seems to be supported by the following code in the code file:

Code: Select all

//Go to Bottom position 
 void g2bot(){
   int x=0;  //kick motor and waite for Photo int ,

controller block diagram.pdf

(47.08 KiB) Downloaded 15 times

Scanner20141219.ino.txt

(15.96 KiB) Downloaded 14 times

[bokks]

Thanks cday for your inputs and ideas. I still couldn't make out from the video's or the diagram how the photo interrupter (apparently located below the book cradle) could sense something because as i understand it has a small gap between the IR LED and the photo transistor as seen in the below picture of a photo interrupter. Maybe there is a different type of photo interrupter available which I am not aware of, or it is placed differently from what is shown in the picture, either way it is still confusing to me.

[cday]

I still couldn't make out from the video's or the diagram how the photo interrupter (apparently located below the book cradle) could sense something because as i understand it has a small gap between the IR LED and the photo transistor as seen in the below picture of a photo interrupter.

The photo interrupter would determine that the platen had reached a certain position through something thin attached to the platen passing between the infra red emitting IR LED and the receiving photo transistor, interrupting the IR light and producing a change in the photo transistor output that can be detected by one of the Arduino inputs.

I agree that it isn't too obvious from the information given what the probably small piece of thin plastic that interrupts the light is attached to, probably more obvious where it could be attached when viewing the assembled scanner, and possibly many alternative places not necessarily actually below the cradle.

The design as we currently think we understand it doesn't address the consideration you originally raised of how variable platen heights when the platen contacts the book being scanned are accommodated: seemingly everything works without specifically accommodating it. There is also probably no fundamental reason for using a photo interrupter rather than one of the other sensor types previously mention, or a Hall effect sensor and magnet, although there may possibly be practical reasons.