Four Cable Drawing Machine Pulls Our Strings


[David] has created a four cable drawing machine for the Telus Spark Science Centre in Canada. Hackaday has featured [David’s] unconventional drawing contraptions before, specifically his center pivot pen plotter. The drawing machine is a new take on a drawbot, and could be considered to be close cousins with [Dan’s] SkyCam. The premise is simple: A stepper motor with a reel of string is placed at each corner of a square. The strings for all four motors come together at a center weight. When all four strings are taut, the weight is lifted off the drawing surface. When a bit of slack is added into the strings, gravity pulls the weight down to touch the sand.

It’s at this point that a simple premise becomes a complex implementation. Moving the weight in one direction is a matter of reeling out string on one motor, and reeling in string on the other. But what about the two “un driven” strings? They have to be slack enough to allow movement in the driven direction, but not so slack that the weight can dig in and tumble on the sand, causing a tangle. To handle some of these questions, [David] called on [Kevin] to write some software. [Kevin] created a custom kinematics module for LinuxCNC to control the drawing machine. The drawing machine runs on Gerber Code, similar to a CNC. Simply feed the machine Cartesian coordinates, and [Kevin’s] module converts to steps.

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Rabiscoscopio – Oscilloscope drawing made easy


If you own an oscilloscope, sooner or later the urge to see something other than signals on the screen will strike. Some people ignore the urge and go about their normal business while others give in, spending hours carefully crafting images, games, and more. The process is time consuming and tricky as our own [Kevin Dady] discovered, but rewards come in the form of geek cred and are hard to pass up.

[Alex] wanted to draw on his oscilloscope, but decided that he would try something other than the microcontroller-based solutions we have seen in the past. He figured the easiest and most accessible way to draw on the scope was with sound, so he whipped up a small application he calls Rabiscoscopio to do most of the work for him.

He starts off by drawing an image using a single line, saving it as an SVG file. This image is converted into an audio file by Rabiscoscopio, which can then be fed directly into his oscilloscope from his PC. That’s all there is to it – it really doesn’t get much easier.

While you could claim that [Alex] is cheating his way through the oscilloscope drawing process, we think his application rocks – after all, hacking is about making your technology work for you rather than the other way around.

Give Rabiscoscopio a try and post the results here or in our Flickr stream – we’d love to see what you guys come up with.

In the meantime, check out the video below to see [Alex’s] attempt at replicating the Garoa Hackerspace logo on his scope.

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[Pythagoras], a Delta Robot for Drawing

[Pythagoras] is a delta robot built originally using RC servos. Humbly, [Aaron] “concedes” that the first version of his delta robot using hobby servos was easy to build. As anyone who has built any kind of robot knows though, there is definitely a lot of work involved in even the simplest robot. Coordinating three axes and programming it to draw a picture is a really great accomplishment.

The second version, however is currently in development and uses stepper motors instead of servos. These upgraded motors should make the robot faster, more controllable, and more accurate. This version is at least somewhat working as evidenced by the time-lapse video after the break.

Although the title page listed above is a little sparse on build details, if you dig deeper into the page, there are actually 15 articles about the ‘bot, so be sure to poke around. Continue reading “[Pythagoras], a Delta Robot for Drawing”

Electrographic Enlarging Sketchifier does your drawing for you


Back in the 80’s, there used to be a kid’s toy that would allow you to replicate an image by tracing a pre-drawn picture in one panel, while a mechanical arm laid down ink in another. We’d be hard-pressed to remember what the thing was called, but this Electrographic Enlarging Sketchifier would be a wonderful modern day stand-in.

flickr user [Imajilon] constructed this cool motorized pantograph out of tongue depressors, rivets, foam core board, and a handful of electronic components. Despite its bargain basement bill of materials, this thing is pretty darn cool. An optical sensor “views” an image and drives a simple FET circuit, replicating the picture automatically using an electrically driven pen mechanism.

Looking through her flickr stream, we thought the results were quite impressive. She does plan on making a second version of the Sketchifier with a smaller light sensitive area, which should allow her to resolve even smaller features of the source drawing.

[via BuildLounge]

Lightdrawing Robot

Long exposure “light drawing” photography has become pretty popular lately. We see images pop up all the time that look pretty cool. [Nils] wasn’t feeling particularly artistic himself, so he made a robot to do the hard work for him. he can program patterns in, and it will replay them by changing the color of the light on top while it drives around. Though it may lack a little of the fluidity of the hand made images, it can probably make up for it with complexity. This isn’t the first time we’ve seen this style of photography mixed with robotics, though this one seems fairly more flexible. Tune in after the break to see a video of it in action.

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Self-portrait machine


[Jen Hui Liao] created a device that guides the user into drawing a portrait of themselves. Dubbed Self-Portrait Machine, it comments on how much in society is created by machines and we are dependent on them. Unlike previous drawing robots, the user is part of the sketching process. The machine holds the users hands and uses stepper motors and servos to move them around like a LOGO turtle. Liao promises to have more details available soon. Video of the machine after the jump.

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