Monson's Servo Auto Scanner

[aeturneus]

Re drawings: right now the whole thing is torn apart while I change stuff and add things so I think drawings would be premature.

Looking forward to seeing what you cook up next!

[jck57]

Idea:

Our community collaborates on design of a 80/20 http://www.8020.net/version of this scanner.

Thoughts?

[daniel_reetz]

I love the idea, am interested in a copy, and for linear mechanisms (or maybe for everything) you should definitely be using MakerSlide by Barton Dring. It's an open source linear rail+extrusion that could potentially solve a lot of mechanical issues.

Store. Forum. Kickstarter (I'm a backer, so is Rob). I'm not sure if it's still going, but for a while Barton had a program where you could suggest an idea like this and he would sponsor the design phase with free materials. Maybe send him a note?

[jck57]

Two improvements:
1. Book size adjustment by screw crank with self-centering feature. Carriage halves are connected to each other by a crank screw. Each carriage half is clamped to a taut, braided nylon mason string run on four pulleys (patio door wheels) attached to the base. As the crank moves the carriage halves in relation to each other, both halves move the same distance in relation to the base, thus keeping book pages centered in camera frames for various book sizes.

2. Cradle face T-slots with T-nut secured book cover clamps made from aluminum window frame.

[aeturneus]

Looks like a solid and well thought-out improvement.

I don't know if I'm sold on an 80/20 or makerslide approach. I'm not sure the parts on offer are the right solution, and cost is a factor. I guess I'm just not sure how it would be an improvement over jck57's current approach.

If we can build it out of wood and standard steel, can't we make DXF drawings for milling both the wood and the steel, for the exact shapes we want?

I just received the parts for my CNC scanner, already painted black by the shop. I just need to pick up the glass (hardware stores here don't carry glass anymore) and I can put it together. The relative ease of sending drawings to a shop suggests to me that good drawings and CNC milling is the way to go.

[jck57]

Looks like a solid and well thought-out improvement.

I don't know if I'm sold on an 80/20 or makerslide approach. I'm not sure the parts on offer are the right solution, and cost is a factor. I guess I'm just not sure how it would be an improvement over jck57's current approach.

If we can build it out of wood and standard steel, can't we make DXF drawings for milling both the wood and the steel, for the exact shapes we want?

I just received the parts for my CNC scanner, already painted black by the shop. I just need to pick up the glass (hardware stores here don't carry glass anymore) and I can put it together. The relative ease of sending drawings to a shop suggests to me that good drawings and CNC milling is the way to go.

What eats up shop time is setting up each piece in the machine. That's why Dan designed his scanner to be cut from a single sheet of plywood. My scanner has a lot of parts that slide during operation or slide for adjustment. I think many of these bits could be made from 80/20 parts without expensive machining. 80/20 could even cut, drill, and tap to make a bolt together kit that arrives in a box.

[jck57]

While I'm at it, how did you cut the steel? A jigsaw or angle grinder or something else?

Nearly all the metal parts are aluminum. I made the slots with a poor man's milling machine: 1/4" end mill in a drill press with the work held in a cross-slide vise.

[revwarguy]

Really fabulous thread!

Couple of questions (out of about a thousand):

How did you find going from the Arduino to the Pololu? Were you able to just use their scripting language, or did you try to
port some of the Arduino code to the Pololu C language SDK? Does the Pololu handle inputs ok? Interrupts?

The reason I ask is I was thinking some input push buttons might be good - a stop and start cycling button, a clear button (for going back a page or two), advance one cycle and hold, etc. Perhaps a pot to control overall speed or camera pause duration. I know, feature creep, I can't help it!

Never used servo savers - can you get them rated by torque value? The ones I've seen don't specify any, so how do you know how much torque is applied before it slips?

I know I've seen them someplace before, but where did you find the acrylic plastic vee parts you use on the end of the pusher arms to clamp the book? Odd as it may sound, I know where to get everything else.

Anyway, Thanks for a great thread!

[jck57]

Really fabulous thread!

Couple of questions (out of about a thousand):

How did you find going from the Arduino to the Pololu? Were you able to just use their scripting language, or did you try to
port some of the Arduino code to the Pololu C language SDK? Does the Pololu handle inputs ok? Interrupts?

The reason I ask is I was thinking some input push buttons might be good - a stop and start cycling button, a clear button (for going back a page or two), advance one cycle and hold, etc. Perhaps a pot to control overall speed or camera pause duration. I know, feature creep, I can't help it!

Pololu scripting language is different but their graphic interface made things easier for me once I got the hang of it. Pins can be set as digital or analog inputs and although I'm not using any that way I think the Pololu can be set up to do the stuff you mention.

Never used servo savers - can you get them rated by torque value? The ones I've seen don't specify any, so how do you know how much torque is applied before it slips?

Would be nice if they were adjustable. The springs in the ones I bought are too stiff so I don't over-travel the servos as I wanted to do.

I know I've seen them someplace before, but where did you find the acrylic plastic vee parts you use on the end of the pusher arms to clamp the book? Odd as it may sound, I know where to get everything else.

Heh. 4" cube plastic storage boxes. Got mine at a rummage sale but I'll bet Target would have 'em.

BTW, I'm scheming up a new version of this that adapts to the Hackerspace scanner. It won't have the pressers with slotted aluminum arms and plastic vees, but will include the other servo gadgets.

Anyway, Thanks for a great thread!

You're welcome! I'm having lots of fun.

[revwarguy]

BTW, I'm scheming up a new version of this that adapts to the Hackerspace scanner. It won't have the pressers with slotted aluminum arms and plastic vees, but will include the other servo gadgets.

You're going to raise the book into the platen by motor control? Hmmm... That probably rules out R/C servos for it. Turning a 5 start screw by a stepper might do it, like a NEMA 23, allowing precise control around the glass. Perhaps a 12V windshield wiper motor would be cheaper, and it would certainly have enough torque. Not much room to place the turning arms inside the box and still get them out of the way of the platen.

Funny, I was thinking about how to flip pages while upside down so that someone bedridden and immobile might be able to read a book, but I guess that would still be best handled by converting the book to digital first, and then placing a display or tablet on a rolling arm.

Can't wait to see what you come up with!