Not all of us have CNC machines, laser cutters and 3D printers, and I’ll bet most of us didn’t start out that well equipped. The low-cost drawing machine that [jegatheesan] made for his daughter reminds us that you can prototype, and then make a functioning mechanical Da Vinci with very basic materials and mostly hand tools. He also wrote his own drawing software, with an interface that has its own simplicity.

There really are a lot of things to like about [jegatheesan]’s project. He first works out the math himself by doing something the likes of which we’ve all enjoyed, digging out the old school trigonometry and algebra books for a refresher. Then he got started on his prototype, made using a cardboard tube for the main support and straws and safety pins for the drawing arms. He already had a motor shield for his Arduino but it supported only 2 servos, so he made his own 3-servo shield. In the end, the prototype told him he had to redo some calculations, allowing him to move on to the final machine.

One thing we can say about the final machine is that hot glue must truly be the maker’s connect-all — you won’t find many screws here. Even the servos are held in place with copious quantities of glue. And the mechanism for lifting the pen is also quite clever. The whole thing is mounted on two vertical guide rods, so that it can easily slide up and down. To get it to actually move up and down, he glued a toy car wheel off-center on a servo arm. When the servo turns, the off-center wheel acts like a cam, pushing down on the wooden base to either lift the machine up or lower it down, depending on where the wheel is in its rotation.

See his hackaday.io page for the full step-by-step development process. But first check out the videos below to see how impressive such a simply made machine is in action.

Not all drawing machines have to be stationary though. Check out this drawing robot that rolls around the canvas in order draw. And if you want realistic portraits done, have a look at this delta robot aptly called Pythagoras.

While initially developed for use in large factory processes, computer numeric control (CNC) machines have slowly made their way out of the factory and into the hands of virtually anyone who wants one. The versatility that these machines have in automating and manipulating a wide range of tools while at the same time maintaining a high degree of accuracy and repeatability is invaluable in any setting. As an illustration of how accessible CNC has become, [Arnab]’s drawing robot uses widely available tools and a CNC implementation virtually anyone could build on their own.

Based on an Arudino UNO and a special CNC-oriented shield, the drawing robot is able to execute G code for its artistic creations. The robot is capable of drawing on most flat surfaces, and can use almost any writing implement that will fit on the arm, from pencils to pens to brushes. Since the software and hardware are both open source, this makes for an ideal platform on which to build any other CNC machines as well.

In fact, CNC is used extensively in almost everything now, and are so common that it’s not unheard of to see things like 3D printers converted to CNC machines or CNC machines turned into 3D printers. The standards used are very well-known and adopted, so there’s almost no reason not to have a CNC machine of some sort lying around in a shop or hackerspace. There are even some art-based machines like this one that go much further beyond CNC itself, too.

Some of our more senior experienced readers may remember a toy called the Spirograph. In case you don’t, it’s a geometric shape drawing toy. The way it works is a plastic disc with gear teeth around the perimeter and various holes on its face is spun around a plastic ring with gear teeth on the inside. A pencil is inserted in one of the holes in the disc and, when spun around the inside of the ring, draws different complex shapes called hypotrochoids.

This was fun enough to keep a kid entertained for a few minutes. It took a while to make a complete shape and sometimes it was easy to mess up (especially if the hole chosen for the pencil was near the outside of the disc). [Darcy] thought it would be neat to combine the Spirograph’s drawing style with modern technology. The result is called the Art-O-Matic and it draws some pretty wild art, you guessed it, automatically.

Click past the break for more!

[Darcy] started the project by drawing all the gears and linkages in Sketchup. A CNC Router was used to cut out the parts, after that just a few bolts and nuts got the mechanics together. In the video below there are 2 geared discs that move the linkage arms. Both arms move independently, one quickly and the other slowly. Each disc is controlled by its own stepper motor. The speed of each stepper motor is controlled by an Arduino. Different patterns are drawn depending on the speeds of the two motors. Switching pen colors along the way adds to the coolness.

Well I sent 2 Doodle Bots to Andrew to show at Makers Faire and for anyone interested I have now put detailed, step by step instructions here:

Instructables: http://www.instructables.com/id/Building-a-Doodle-Bot-kit-from-DAGU/

MAKE Projects: http://makeprojects.com/Project/Building-a-Doodle-Bot-kit/2627/1#.UGbsra4_5Sm

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The Doodle Bot is a very simple robotic platform for beginners, students and hobbyist.

The Chassis is a simple laser cut panel with two ball raced geared motors and a servo for raising and lowering a white board marker, jumbo chalk or crayon. Each wheel is fitted with an 8-pole magnet that is monitored by hall effect sensors to form two simple wheel encoders.

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Nice tutorial about how to make pencil drawings reactive to touch using just pencil, some resistors, paperclips, wire, Arduino and tape.