auto page turner prototype

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dtic
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Re: auto page turner prototype

Post by dtic »

univurshul: thank you!

Tim: Right, moving the cradle will at least lessen the "page pile" height problem. I hope that can be enough but it needs testing.
There's still need for some way to adjust the finger position given different sized books. Though that's only needed once for each book and can be manual.

Motor control for cradle left moves sounds straightforward to do. Either a stronger motor and cradle friction. Or a weak motor, cradle on easy sliding rail plus something that autolocks cradle in place between moves. In the latter case a small RC servo with Arduino might work since the distance to move the cradle is so short.
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daniel_reetz
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Re: auto page turner prototype

Post by daniel_reetz »

All I can say is... start simple. Page fluffers, compressed air, servos, etc are great, but you got this far with nothing more than string. Great stuff.
Mathue
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Re: auto page turner prototype

Post by Mathue »

dtic wrote:
a.jpg
See attached video (zipped .mkv since upload form didn't allow mkv). The "big finger" is a rubber eraser. The "small finger" is a thick drinking straw. To use a double platen you'd need two (properly timed) forces. Reliable finger action is a challenge but the device now performs fine on a 30 page test run.

edit: youtubed video here
That is AWESOME!
dtic
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Re: auto page turner prototype

Post by dtic »

update: I'm stuck on moving the platen up/down. Mini servos powered by the Arduino board can't handle that even with counterweighting. Too much friction. I have salvaged some more powerful components from a printer but need to read up/"get adviced up" before proceeding. I made a post in the Arduino forum in hope of some help. But any feedback here is also welcome.
http://www.arduino.cc/cgi-bin/yabb2/YaB ... 429937/0#1
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rob
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Re: auto page turner prototype

Post by rob »

Make sure that your platen doesn't "stick" due to friction -- the platen movement needs to be smooth -- and also make sure the movement is not finicky before you can motorize it, otherwise you're just using a powerful motor to power through the original design problem. I want to emphasize "finicky" because on some platen designs the force you apply to move the platen needs to be at a precise angle: when you move the platen manually, you often don't notice this because you automatically adjust.

This is why I moved to a platen on an axle rather than on slides (see: this post). I found that the slides were just too finicky, while with the axle, all you had to do was turn it.
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dtic
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Re: auto page turner prototype

Post by dtic »

Ok, I use slides at the moment. I have two "platen slides towers" on each side of the platen so it can't wobble much. But I'm suspecting that I'd need a motor on each side. If I apply upward force only at the platen part attached to one slide then I get some friction at the other side. I added the extra tower in the first place because I worried the platen would sloop down if not secured on both sides. The friction is not enormous. It is just that the tiny servo motors are very weak.
dtic
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Re: auto page turner prototype

Post by dtic »

I tweaked the counterweighting and now think that a smaller motor (5v) is enough, and only on one side.

Are there any examples of motorized platen movement that I can learn from? My working idea is to put motor+cogwheels on the platen base and then a matching jagged plastic rail on the platen tower. An alternative would be a wheel, a motor+cog and a fan belt on the tower side and then something that secures the platen base to the fan belt. Any other ideas?
dtic
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Re: auto page turner prototype

Post by dtic »

Here are some images of what I'm trying to reuse for this. The 5v motor is too weak (at least in combination with the belt part). I need to use one of the stronger ones. But I need some way to attach the motor cog to the right plastic cog. Any ideas on doing that? I don't think glue will be enough for these motors. Plastic padding or something similar maybe? Any other secure-a-cogwheel-to-a-motor suggestions?
Jagged rail on platen tower, salvaged 5v motor+cogs on platen base. But too weak to lift the platen even with counterweighting.
Jagged rail on platen tower, salvaged 5v motor+cogs on platen base. But too weak to lift the platen even with counterweighting.
1.jpg (95.69 KiB) Viewed 10888 times
close up on 5v motor+cogs.
close up on 5v motor+cogs.
3.jpg (34.22 KiB) Viewed 10888 times
2 motors with more power + extra cogs.
2 motors with more power + extra cogs.
2.jpg (78.1 KiB) Viewed 10888 times
dtic
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Re: auto page turner prototype

Post by dtic »

I have scrapped the jagged rail idea. I instead aim to use the larger motor depicted (a stepper motor I think) to power a spool that winds a line secured to the platen. That allows upward lifting. Then I'll let gravity move the platen down when unwinding the spool.
I'm stuck on getting the parts needed, and figuring out the right circuitry, for the motor though. If anyone can assist with such things please see the arduino thread posted above.

I have the other parts of the machine in place. The "fingers" are working already. I also have a tiny servo driven rail that will move the book holder to the side, I just need to mount it in place.
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daniel_reetz
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Re: auto page turner prototype

Post by daniel_reetz »

If anyone can assist with such things
I can, but it might be a day or two before I type something up...
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