What happens if you try to turn a stopped stepper?

[kingofkya]

Keep it simple guys

What about a small string with knots tied in it. the --- are string and the ++ are knots and = is a page. Note the last page is tied on both sides this lets it reset the entire stack.
-+=-------------------+=-------------------+=-------------------+=---------------+-----

Then just a small dc moters will pulleys on them. string is red. You could do it with one moter but you need to keep tension in the other side somehow. So it can unwind. I am assuming your pages are ridged.

ugh nvm physics are in the way. It would need some way to un hook the page on the other side. Or maybe multiple pulleys for each page?

 

[LightUp]

... And I was imagining that the book would be tilted back some (at say a 15deg angle) so that I could use gravity to help the pages fall into place when turning if need be. ...

Did you also indicate that there may be some text on the page for the audience to read? If so, would it not require a greater angle than 15 deg to read properly?

 

[toozie21]

I had thought of the string approach as well and came up with the same issue as well.

The 15 degrees was tilting the book back so it wouldn't be straight vertical.

Sent from my DROID BIONIC using Tapatalk

 

[kingofkya]

I think you could do it with 1 string per page but you would need some kind of clutch on each wheel. Or multiple moters.
There must be a simple mechanical way...

I think i got it if you cut 2 holes like this, then get some bouncy balls or something simmaler maybe a round bead. Then when the page is on the right the round thing is in the lower side that it cant fit in and once the page gets near the end the round thing then moves to the top and pops out the other side. You woudl have to place the pulley on the right above a bit higer then the other to do this.

 

[kingofkya]

OR going of the same though process a belt maybe made from http://www.uline.com/cls_09/Strapping
then have a pieces glued to it that just looks like and upside down T so it could pull though a slot in the page when it gets to the other side.

You would probably need to have some separation between pages so on reset the pages end up with the T tabs on the right side(hide in the box below maybe)




Then one more this is the pages would have to have an extra tab so you could use it as a stop when the pages go below. Like a file folder. Each tab would be in a different spot so it could stop at the bottom.

http://www.staples.com/Staples-Mani...9&srccode=cii_17588969&cpncode=33-269674710-2

 

[Roterhead]

Here's a different take on page turning..

Consider the use of Model Servos. One servo per page, so 4 servos needed. Adjust size of servo to handle torque needed to turn the pages. Page turning speed and slow / fast can be easily adjusted.

Mechanical: Use spring steel wire (very high strength, bends but will spring back, used a lot in Model aircraft) arranged in a brass tube acting as a bearing.

Take a look at the attachment and see what you think....

 

[toozie21]

I had a potential idea this evening, but I don't know how well I will be able to articulate it in words, so bear with me (and I definitely don't have the drawing skills to show you).

My thought starts with each page having the tabs sticking out of the bottom like kingofkya's manila envelope idea. These tabs will be at different points on different pages (say the first page has the tab 6" from the hinge, second page is 5", third page is 4", etc.). Next I have a disc underneath with pins sticking up vertically from it. As the disc turns, the pin would catch the tab sticking out the bottom of the page and rotate it (to turn the page). If I do the math right, the disc would never need to rotate a full 360 degrees, so the pins would be spaced around the disc. With me so far?

This is something that I've considered in the past, but what I thought of that would be different this time is to not have the disc parallel to the bottom of the book, but to have a downward incline so that the part of the disc that is closest to where the pages will land when opening the book is closer to the ground (sloped downward). By doing this, the tabs will be out of the way as the disc turns around, yet will also not be in the way as I reverse the disc and reset the book (also where my previous plans failed).

What I would need is one special pin that when the book is resetting, it catches the first page (even though there is an incline, so it would be taller) and pushes it (which pushes all the other pages as well) back to the starting position. If I put a microswitch to detect when the special reset pin is in a position that all the pages must be at the beginning, I will have a "home" position for the stepper, as well as a way to know that I need to stop the motor and not break anything.

OK, now is where you can poke holes in my idea. Seems solid to me, but so did the previous 108 ideas I had for this project...... One of my big concerns with this idea is, would a stepper have enough torque to handle this, in particular, the turning of the pages back to the beginning (since it has to turn all the pages at once).

 

[LightUp]

.... One of my big concerns with this idea is, would a stepper have enough torque to handle this, in particular, the turning of the pages back to the beginning (since it has to turn all the pages at once).

Once you build a prototype you then can pull the pages using a "fishing scale" to approximate how many oz. pull it takes to turns all the pages. You then compute a rough torque number. If your stepper is too low you could use gears, or pulleys, to increase the torque from the motor.

 

[toozie21]

Once you build a prototype you then can pull the pages using a "fishing scale" to approximate how many oz. pull it takes to turns all the pages. You then compute a rough torque number. If your stepper is too low you could use gears, or pulleys, to increase the torque from the motor.

Interesting idea on the fishing scale. A low-tech way to get an answer, something I would have NEVER thought up on my own!! I believe would would need to be done is take the measurement of the rotation point from the axis in inches, and multiply that by the value on the fishing scale (in oz), this will give me a oz-in measurement that I can use to compare to the ones on the stepper (like a 70oz-in stepper). Of course, any wind on it when trying to turn will add to that value, so I would probably need to pad my overhead quit a bit.

The one catch I've been able to come up with since my idea last night was that I might have an issue with the disc since it is a radial motion around a central access, yet the pages all have different axis points. By picking the center axis, it might be close enough (as long as I leave some fudge factor with the tabs), but I will probably have to play with it to figure it out.

 

[LightUp]

Interesting idea on the fishing scale. A low-tech way to get an answer, something I would have NEVER thought up on my own!!

Neither would I, except that when I did some work on reel-to-reel tape recorders, many years ago, we needed to make tension adjustments on some parts and we had special little "fishing scales" to do the job. Hence the idea stuck.