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.
Finally, I was waiting for someone to copy the kick starter: http://www.kickstarter.com/projects/line-us/line-us-the-little-robot-drawing-arm
See also: http://www.buildlog.net/blog/2017/02/a-line-us-clone/
(and poke around his blog for further developments on the project)
cool project. similar to the plotclock project few years back. the most complex thing about these projects is the inverse kinematcs, Plotclock guys provided some explanations and a source but I never actually understood the code, especially all the atan2 stuff. This project does not even provide a source, only a compiled EXE file that does all the work and sends commands to the arduino. too bad. Does anyone know a good source for learning IK for drawbots please post it.