Build a Computerized Etch-A-Sketch

By Alan Nishioka

Maker Faire





Parts List

Description Quantity Manufacturer Vendor Price Notes
Etch-A-Sketch 1 Ohio Art Ohio Art 505 $12.99
Travel Etch-A-Sketch 1 Ohio Art Ohio Art 555X $8.99
Pocket Etch-A-Sketch 1 Ohio Art Ohio Art 515X $4.99
Unipolar stepper motor
12VDC 30ohm
2 GBM 42BYG228 Jameco 155432 $18.99 Red/Black/Blue, Yellow/White/Brown
M3 mounting screws data
Unipolar stepper motor
9.6VDC 32ohm
2 Oriental Motor StepperControl.com NEMA17 $20.00 Red/Black/Yellow, Green/White/Blue
4-40 mounting screws
Shaft Coupler 0.197" 4
Jameco 161998 $1.19 M3 set screw
Shaft Coupler Rubber Spider 2
Jameco 162000 $1.55
Plexiglass mount 1
TAP Plastics $20.00 drawing
Plexiglass mount 1
Front Panel Express $22.84 design file
Dual Axis Stepper Controller 1 StepperControl.com A-100 StepperControl.com A-100 $45.00
Dual Axis Stepper Controller 1 DIY Electronics Kit-113 Circuit Specialists Kit-113 $22.95 manual pcb software ZTX1053A data

Vendors

The Ohio Art Company
One Toy Street
PO Box 111
Bryan, Ohio 43506-0111

Jameco
1355 Shoreway Road
Belmont, CA 94002-4100
Phone: 1 650 592-8097
Fax: 1 650 592-2503
Order: 1 800 831-4242
Customer Service: 1 800 536-4316
Email: info@jameco.com

An excellent source for electronics

Circuit Specialists Inc.
220 S Country Club Drive #2
Mesa, AZ 85210
Phone: 800-528-1417 / 480-464-2485
Fax: 480-464-5824
Email: jr@cir.com

Another excellent source for electronics

Marlin P. Jones & Associates
PO Box 12685
Lake Park, Florida 33403-0685
Phone: 800 632-6733
Fax: 800 432-9937

DIY Electronics (HK) Ltd.
PO Box 88458, Sham Shui Po
Hong Kong
Fax: 852-2729 1400
Voice: 852-2304 2250
Email: ladda (AT) kitsrus.com

StepperControl.com
Unfortunately, they are out of business and no one seems to have continued their product line. However, their website is still active and has good information.

Oriental Motor
Makes stepper motors.

Front Panel Express
5959 Corson Avenue South, Suite I
Seattle, WA 98108
Phone: (206) 768-0602
Fax: (206) 768-0679

I like this service. You download a cad program from them and draw your panel. With a few clicks, the design is uploaded to them and you get parts in about a week. Supposedly for making front panels, you can make any flat panel out of plastic or aluminum in many different thicknesses.

TAP Plastics
3011 Alvarado Street
San Leandro, CA 94577
Phone: 510.351.0422
Fax: 510.351.0425

Will fabricate plastic things from your drawing. I used a Microsoft Word drawing, but I should have used DXF (Autocad).
They took about a week to laser cut 10 pieces. They have a $120 minimum order for laser cut projects.
I have the extras for sale for $20 each.

Mechanicals

Coincidentally, the Etch-A-Sketch knobs and the stepper motor shafts are all 0.197 in diameter. I used couplers and spiders so the setup is more forgiving. They also make it easy to disconnect for erasing.

I drilled holes to accommodate all the different models of Etch-A-Sketch I could find. Ohio Art recently changed the size of their large Etch-A-Sketch. Luckily all models have the same shaft size.

Software

I used Debian Linux as a development platform because I like Linux and it is easy to access the hardware directly.
These programs must be run as root because they write directly to hardware.

A flutterwumper is Don Lancaster's name for a sort of milling machine. He wrote some code to extract outlines from a Postscript file.
The .ps files below were run through Ghostscript to create the .flut files. flut.c was then used to plot the .flut files.

Inkscape is a wonderful vector graphics drawing program. I used it to create and edit outlines. These were written as Postscript then processed and plotted.

Picture Description Source Version Notes

Makefile used to build all source below Makefile 1.12

Library routines used in all source below libesketch.h
libesketch.c
1.6
1.17


Used to draw .flut files below flut.c 1.6

Used to draw .hpgl files below hpgl.c 1.6
Draw a spirograph spiro.c 1.3
Draw a spiral spiral.c 1.3
Draw string art string.c 1.3
Draw a star star.c 1.4
Draw snoopy snoopy.ps
snoopy.flut
snoopy.hpgl


Draw self portrait self.ps
self.flut


Draw the author's portrait alan.ps
alan.flut

Started with JPEG from camera.
Used autotrace utility in Inkscape to convert to vectors.
Draw a heart heart.eps
heart.hpgl


Problems & Solutions

1. Etch-A-Sketch wires stretch, so fine details get lost
To fix this, I step an extra four steps on each draw command, and then back off four steps. This overcomes any stretching while maintaining the absolute position.

2. Modern computers don't have parallel ports
I am looking at USB printer adapters to see if they will work.
I looked at a serial port stepper motor controller, but this didn't have the required flexibility. Also, many computers don't have serial ports either.

References & Links

Don Lancaster at www.tinaja.com is an excellent resource for all sorts of electronics projects. Included is a web page of Flutterwumper resources. Many of these involve stepper motors. Tech Musings, Electronics Now, October 1999 contains a discussion and a circuit for a computer controlled printed circuit drill. It uses stepper motors and Don writes about how it could be controlled from PostScript.

Sreejith N writes about controlling a stepper motor from Linux. His example uses a real kernel device driver.

USB2LPT by Henrik Haftmann is a project to driver parallel printer projects from USB

Fun with LCDs talks about using USB to Printer cables to drive hardware projects. Convertors that use the USS720 or USS725 chip can be driven with a simple register commands. Unfortunately, I have not been able to find one. Most cables use a PL-2305 which cannot be used this way.

A great introduction to stepper motors by Jason Johnson.

Datasheet for ULN2803 Octal High Voltage, High Current Darlington Transistor Array from On Semiconductor, (formerly Motorola).

How to use disk drive stepper-motors is an article by Tomi Engdahl about using stepper motors from old disk drives. Old disk drives have many useful parts and are often very inexpensive or free. Unfortunately, the stepper motor I tried was too weak to drive an etch-a-sketch.

The Etch-A-Sketch is a featured toy in the movie Toy Story.

It's amazing what some people are able to draw with an Etch-A-Sketch! Check out the art gallery at www.etch-a-sketch.com.

The Etch-A-Sketch was invented and patented by Arthur Granjean in 1962 ( US patent #3,055,113 ). A follow-up patent ( US patent #3,760,505 ) was granted in 1973 for the plastic coating to keep the glass in if it should break, and a method for sealing the aluminum particles in the toy.

MIT has a good history of the development of the Etch-A-Sketch.

Visit Etch-A-Sketch Technical Support if you have trouble using your Etch-A-Sketch.

ETCH: Extensible Testbed for Controlling Hardware is another computerized Etch-A-Sketch. Unfortunately, this page is broken and is not being updated.

Neil Fraser has built his own Computerized Etch-A-Sketch using Meccano.

Electr-O-Sketch. Jason Levin & Chris Hopkins used an Atmel Mega 32 to control the movement of an Etch-A-Sketch using a typical serial mouse.

Scott Ferguson has a project called CNC Etch-A-Sketch.

About the Author

Alan Nishioka designs professional video equipment for the broadcast market. He can be reached at alan@nishioka.com.


Last modified $Date: 2007/05/30 20:56:35 $