how to build a drawing machine

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PraveenAlexis
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Re: how to build a drawing machine

Post by PraveenAlexis » Wed Jul 27, 2011 2:13 pm

Imagei could find some motors from my old brocken DVD-Rw ;)
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Neo
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Re: how to build a drawing machine

Post by Neo » Wed Jul 27, 2011 7:27 pm

New topic added, How to control Hard Disk motor using a microcontroller ;)

Rksk,
Remember I was talking about the tray motor of the CD ROM. Accidentally I found a video on that. It's a stepper motor.

Ability to control position accurately without a feedback system (such as using an encoder) is a feature in a stepper motor. Since the angle movement per pulse is well defined, it is easily possible to control the angular velocity using a little microcontroller.

[media]http://www.youtube.com/watch?v=dSKac6EPkrc[/media]
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Re: how to build a drawing machine

Post by Neo » Thu Jul 28, 2011 1:09 pm

Information here are related to donation topic here.

According to the doc How it Works.docx, you will need to apply an edge detecting filter to convert the source picture to machine printable drawing. This subject comes under Computer Vision -> Edge detection. I would like to propose either Sobel or laplacian filters.

Source Picture
original.PNG
original.PNG (118.44 KiB) Viewed 14660 times
Destination machine printable drawing
sobel.PNG
sobel.PNG (97.39 KiB) Viewed 14660 times
First you need an image reader (Such as JPG reader) and then apply this sobel filter to get the edges that are ready to be sent to the printer. Finally output the data line by line (called vector graphics).

I can help you to do this since I have done these in past. Let me know.
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Re: how to build a drawing machine

Post by Neo » Thu Jul 28, 2011 3:29 pm

Keep these circuit diagrams with you guys.

Power supply
Since the motors are 12V, find a 12V / 2A transformer to suit both needs. 7805 will provide essential 5V and power to the uC (microcontroller).
Power supply.jpg
Power supply.jpg (29.95 KiB) Viewed 14659 times
Stepper motor control with ULN2003
uln2003.gif
uln2003.gif (12.27 KiB) Viewed 14659 times
Oscillator & MAX232
MAX232.jpg
MAX232.jpg (252.53 KiB) Viewed 14659 times
Lots of exiting things to happen ;)
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Re: how to build a drawing machine

Post by PraveenAlexis » Thu Aug 11, 2011 11:00 am

motors.jpg
motors.jpg (33.9 KiB) Viewed 14633 times
1) The two accells
2) Cartridge Holders
3) Stepper Mortes x 3
4) Normal DC motors x 2
5) Belts x 2

Neo, can you make this pic small :) i dont know how to do it :roll:
Last edited by Neo on Thu Aug 11, 2011 11:40 am, edited 1 time in total.
Reason: Image resized and uploaded :)
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Re: how to build a drawing machine

Post by Neo » Thu Aug 11, 2011 12:56 pm

So you have enough items to give a start. Next thing is to give a start. I'll give you some guidelines.

First thing is to design the structure. I think threaded rods can be easily used for moving parts. You can easily find them in local hardware shops.
  1. Sample structures
    struct.jpg
    struct.jpg (61.59 KiB) Viewed 14632 times
    1, 2 and 3 are 3 threaded rods that are fixed to 3 stepper motors to move along x, y and z.

    Another sample structure:
    struct1.jpg
    struct1.jpg (18.31 KiB) Viewed 14632 times
    The one in https://robot.lk/viewtopic.php?f=75&t=2594#p7607 is also a good example.
  2. Threaded rod
    threaded-rod.jpg
    threaded-rod.jpg (11.88 KiB) Viewed 14632 times
  3. Mounting motors to threaded rod
    threaded-rod-motor.jpg
    threaded-rod-motor.jpg (34.99 KiB) Viewed 14632 times
    threaded-rod-motor1.jpg
    threaded-rod-motor1.jpg (16.71 KiB) Viewed 14632 times
  4. Fixing the other end to a Ball bearing
    threaded-rod-ballbearing.jpg
    threaded-rod-ballbearing.jpg (35.9 KiB) Viewed 14632 times
  5. Fixing a nut to moving part
    threaded-rod-move.jpg
    threaded-rod-move.jpg (15.97 KiB) Viewed 14632 times
  6. Once we are done with the structure, it's about moving the motors in x, y and z directions using electronics.
Since you have few people on the group, you can ask someone to identify the wires, voltage & current ratings and angle per step of each stepper motor.

We can discuss about the electronics part later.
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Re: how to build a drawing machine

Post by PraveenAlexis » Thu Aug 11, 2011 1:22 pm

shenal is working on the electronical parts, and im working on the structure ;) shenal have an idea about moving the pen up and down without the stepper, he will explain you when hes done with it, :)
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Re: how to build a drawing machine

Post by Neo » Thu Aug 11, 2011 2:51 pm

shenal have an idea about moving the pen up and down without the stepper
I guess he is going to use a solenoid? If that is the case, I think it's a good idea as long as he can control the pen on hitting the paper slowly (using a spring may be) to avoid damage to both paper and pen. We can discuss that later.
im working on the structure
Good luck!!!
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Re: how to build a drawing machine

Post by PraveenAlexis » Sun Sep 04, 2011 10:45 am

we finished making the structure! Nw we have to do the electronic part! I wish shenal will reply here soon!
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Re: how to build a drawing machine

Post by Neo » Sun Sep 04, 2011 1:38 pm

A picture is worth a thousand words !!!

Can you update with some pictures.
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