Automated Etch-a-Sketch Re-Produces Famous Artwork

Unless you’re some incredibly gifted individual with more dexterity than a fighter jet pilot, making anything on a Etch-a-Sketch is hard. So [Evan] decided to motorize it, and cheat a little bit.

She’s using an Arduino Uno to control two stepper motors that she has bound to the Etch-a-Sketch knobs using a short piece of rubber tube and Gorilla Glue. She 3D printed some custom motor mounts to allow the motors to be positioned directly above the knobs, and a ULN2803 to switch the 12V required for the steppers.

After she had the hardware all setup, she coded a simple Python script to take in .PNGs and produce vector art to be sent through the Arduino. In case you’re wondering, an Etch-a-Sketch has approximately 550 x 370 pixels, or about 500 x 320 for the “safe zone”.

Due to the limitations of the Etch-a-Sketch, like its inability to stop writing, some images might require some editing before sending it off to your new Etch-a-Sketch printer.

While Etch-a-Sketches have been the bane of existence for many people’s childhoods, there’s quite a few hacks out there of people getting their revenge. Etch-a-Sketch clock? Check. Etch-a-Sketch CNC? Check. Etch-a-Sketch Automatic? Check.

25 thoughts on “Automated Etch-a-Sketch Re-Produces Famous Artwork

  1. Did something similar to this a while back, to make a project for students to use in a lab. We found that the belts that drive the axes of the etch-a-sketch (or whatever chinese knockoff we were using) didn’t last long against the abuse of bad code.

  2. [I’m going to be “that guy”…]

    No, an Etch-a-Sketch does not have a resolution of approximately 550 x 370 pixels. The Etch-a-Sketch is an analog device that has no pixels whatsoever.

    However, stepper motors have a discrete angular distance in whole steps (such as for example, 200 steps per complete revolution which equals 1.8 degrees per step). This can be increased in the electronics using micro-stepping techniques to get finer increments that the whole steps.

    So a given stepper-motor driver assembly will have a specific resolution.

    An Etch-a-Sketch driven with different motors and/or electronics will have a different resolution.

    1. I can only assume they divided the dimensions of the window by the thickness of the line drawn. Getting really close to an existing line and even overlapping might have adverse effects, IIRC my childhood.

    2. I’m going to be “that guy” too… I do 3D printing, so I get asked the 3D printing version of this question often. Same basic answer but… we do use a NOZZLE that has a diameter. What people usually mean when they ask for resolution is, how many times can I stamp that nozzle across the area (not volume) of the buildable volume, and that question at least has a discrete, countable answer.

      For etch a sketch, the stylus has a non-zero size, and I think that should determine resolution moreso than “how many discrete positions can I turn the motors to”

    3. No, sorry, the resolution of the etch a sketch is an intrinsic function of the etch a sketch itself, not of any motors you attach to it.

      The resolution and repeatability will be determined by the super duper cheap and cheesy plastic mechanical components that comprise its drive system. You are NOT going to get micro-stepping accuracy from the cheeseball plastic gears in a cheap toy.

    4. heh! just a side note* As far as I understand it, Micro-stepping doesn’t really add more resolution either, as the motor doesn’t have any holding power at these finer increments. Micro-stepping simply helps the motors run smoother. This can leave a smoother finish but shouldn’t really be considered as “more Steps”, which is what you would need for higher resolution (well I guess you could gear your motors too but that’s off topic, kinda) :D

      1. Sorry, you are wrong. When mircrostepping, they really position themselves between the steps. But there are some drawbacks! The positioning accuracy depends on the design of the tooths’s and coils inside the stepper motor.
        There are steppers specifically designed for higher accuracy in microstepping mode!
        But still, the angular movement per microstep varies with the angular position of the shaft. Shure, the sum off errors is zero every time you reach your starting position when doing a full rotation, but the differential nonlinearity varies in a sinusoidal way through the turn cycle.
        A good article can be found here:
        http://machinedesign.com/technologies/microsteps-mega-benefits
        But you are right with the holding power at the in between steps.

    5. It’s correct if “resolution” is used like it is in analog TV, meaning picture element (pel) density. In analog TV the resolution in the horizontal direction is the maximum number of color changes that can be fit into a horizontal scan line while the individual color changes can still be resolved–it can be determined using a resolution chart with vertical lines that converge. In both analog TV and an Etch-a-Sketch, a color change can happen at any analog position, but only so many changes can fit limited by the bandwidth of the signal in TV and by the width of the stylus in the Etch-a-Sketch.

      By the way, this is one reason why the tiny credits an analog video image can still be legible while the same-sized credits will be illegible on a digital image with more pels per inch. The analog pel can’t be as narrow as the digital pel, but can start and end anywhere unlike the digital pel.

    1. the audio in part got me thinking – what about using the etch-a-sketch as an incredibly slow oscilloscope?
      you could even have a shaking mechanism or an electromagnet to clear it.

  3. The ultimate hack of an Etch-a-Sketch would be to come up with a way to pull the stylus back from the panel so it can do discontinuous lines. Perhaps attach a neodymium magnet to it inside the device then track it with an electromagnet on a gantry behind the backplate? Likely enough give in the internal mechanism to allow the stylus to be pulled back just a little.

    1. Good idea, except that would require opening what is essentially a box of (I think) powdered aluminum, and keeping said powder inside said box as you attempt to attach a magnet to something covered in said powder. Not even that easily said, much less done :P
      Be sure and post lots of pictures when you do it, though, because that would, indeed, be the ultimate EaS hack ;)
      Also, you might not need to actually track the stylus. You could just have a magnet with a very large pole that covers most of the back of the EaS. It probably wouldn’t need to be that powerful, either.

    1. You’re definitely not the only one! I did an ‘etch-a-sketch photo booth’ in college. The software used openCV and python and worked pretty well. Unfortunately, there was essentially no repeatability on the etch-a-sketches with the motors I used. Way too much slippage. I became so frustrated with this, I began thinking of ways to replace the stylus mechanism. I opened up an etch a sketch and quickly gave up.

      1. I should add two points
        1) He says in the description on his github readme that lines longer than 75 “pixels” will introduce error.
        2) Someone really should do a closed loop etch-a-sketch. Put a camera above it and use openCV to make sure the current stylus location matches the expected location. One of the thoughts I had before I opened up the etch-a-sketch was to put an IR LED on the stylus to make it very easy for the openCV software to track the location. After I opened it up, I was covered in powder and hated everything about etch-a-sketches.

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