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Build Your Own Electric Etch-A-Sketch
mhaisley writes "Ok, case mods are cool, monitor mods are nifty... but an Electric Etch-a-Sketch beats either. Students at Cornell University built an electronically controlled etch-a-sketch, controllable by a PC mouse. This was part of a group of class final projects featured by their instructor."
User: My Etch A Sketch has crashed what should I do?
Support: Shake it.
It is called photoshop.
maybe now i could actually draw a circle on the freaking thing
i always saw kids in the commercials w/ these elaborate trucks drawn, i couldn't even make a damn circle
not that im bitter...
...and that's all there is to it.
I think they should just drop the mouse, hook it up to a computer and draw fractals. That would be a really cool project and it would make some pretty cool results.
If you could use the expandable shapes like the circles and rectangles and stuff in most paint programs and the machine would just make it?
I are winner
...the Etch-a-Sketch itself (yeah, yeah, I know they got it for free but you could source one for a dollar). I am impressed with this project as a teaching aid. Combines a whole lot slew of concepts in one fun project! So what if it isnt practical - technlogia gratia artis.
See that long UID - that's what you get for lurking too long
A class a few years earlier built an scanning tunneling microscope. http://instruct1.cit.cornell.edu/courses/ee476/Fin alProjects/s2002/sm242/index.htm
Hey There,
... ... ...
... ... ;)
What the needed to do was
supply a image as input
and have the thing
A) Translate it to b&w
B) Have the EAS automatically draw it
Kind of like the novelty of
translating an image to
ascii
Cheers,
--The Dude
Well.... In the poor guy's defense, I know I couldn't have built an LED that counted in binary at the end of my second year of school. I assume that his community college only counts to 10 like most others.
When I tell an object to delete this, am I killing it or telling it to kill me?
I built one of these years ago... the thing mine had that theirs is missing is some way to flip it over to erase it.
I used a big servo (made for a remote controlled boat) to flip it over. Also a solenoid to lock the screen in the vertical position so that the servo/solenoid only need to be energized while the screen is being shaken.
An LED that counts in binary isn't hard -- if you use a flasher LED: 0 1 0 1 0 ...
One line blog. I hear that they're called Twitters now.
Imagine, a 3d engine which can render 20 polygons a minute!
"You lied to me! There is a Swansea!"
I think the most interesting thing here is the wide range of projects of their class page and how they have come up with inventive ways of using microcontrollers (sure some of them aren't new but that doesn't mean they aren't cool work for a class of students).
But if you think this is cool then you should check out the work of Bruce Shapiro. He's got a stepper motor controlled Etch a Sketch, but that's only the begining. How about a home built two axis plasma cutter, or a an old dental mill that turns 2d pictures into 3d sculptures.
Sin lies only in hurting other people unnecessarily. All other sins are invented nonsense. - Robert A. Heinlein
... articles about nifty microcontroller projects like the laser-based Iridium flare tracker get rejected. Go figure.
Is that all there is to it? A mouse moving the stylus of an etch-a-sketch? Now if it incorporated a "drag and drop" or "selective erase" feature, it might be interesting. As it is, this would make a neat high school science fair project, but a final project for an EE degree?
Why was a microcontroller even NEEDED here? Rewiring the mouse to provide the raw X and Y encoder wheel pulses, and applying them right to the stepper drivers would give substantially the same results without the MCU and all the programming. If the stepper drivers need step and direction signals rather than quadrature pulse trains, run the encoder signals through one of the LSI/CSI encoder interface chips to get whatever you want without writing code or burning it onto a chip. A programmable solution for something this simple seems like complexity for complexity's sake...
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There was the Iconarama, which was an Etch-A-Sketch like device attached to a projector. This was the first large-screen computer controlled display, and was used by NORAD in the 1950s. The device scratched transparent areas onto a slide, projecting icons (usually aircraft tracks) on a screen. When the screen became too cluttered, a slide changer loaded a new blank slide. Two complete systems aimed at the same screen were used, to avoid a blank period during slide change and redraw and to provide redundancy.
The Iconarama was one of a long series of early military attempts to build large-screen displays. There were wall-sized plotters. CRT/film/photo processor/projector combinations. The Eidophor oil-film projector.
Eidophor technology first appeared in 1943, and there are still a few units in use. No other technology until DLP could reach the 4000 lumen light level of an Eidophor unit.
When I took a class on controls a few years ago there was a class project you had to do, build something that you would control. Could be anything. One of the things the prof wouldn't let us do is this. It had been done so many times before and had a couple etch-a-sketches sitting in the cabinent with motors allready on them.
This is something students have probably done for such projects for 15 years.
Inside the mouse is a ball driving two optical encoders: one for X, one for Y, mechanically placed 90 degrees apart.
The optical disks and detector are made in such a manner as to produce a quadrature encoded output.
With very minimal "glue logic", these signals could be changed to the quadrature encoded drive signals required by a stepper motor.
This would have eliminated the whole processor.
But, they used a roundabout way of doing it.
I'll often do things for my own edification that are not optimal just to see how things work.
In this case, the students got to experience working with the AVR compiler, programming in machine code, and real-world interface design, so I won't bang on them for not doing it in such a way I would have if I were gonna make a million of 'em.
Now, if I had found out that they were just drawing lines on the CRT screen, I would have posted a very vile commentary on the state of what is passing for education these days. What I saw looked appropriate to me for a class project for BSEE.
Just for funsies, my final project in College back in the early 70's was building my own oscilloscope from scratch. I thought I was gonna get really good bandwidth because I was using 45MHz IF tubes from television receivers as my CRT drive. Got my design finished... Surprise! I got 10KHz! Well, so much for my rude awakening to plate resistance and capacitive loads... but the professor gave me full credit anyway because I offered the correct explanation of why I didn't get the response I expected.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
Cornell has turned itself into a Microsoft shop, so it's appropriate that they're all excited about something that others did years before.