Loving to draw but deathly afraid of pen ink, [Marcel] came up with a little drawing machine made out of Lego that will do it for him. It’s not a very complicated build but it does have several different components arranged such to complete a task, and that in itself is cool. Oh yeah, just kidding about the “afraid of pen ink” thing.
RC Car Servos are used to drive the pen in the X and Y directions. These servos only have a 180 degree range of motion which is not enough to move the pen very far. To increase the pen’s travel distance, [Marcel] attached a large gear to the servo which rotates a much smaller gear that rides on a rack gear attached to the bed. A Lego hinge takes the place of a Z axis and is used to set the height of the pen that is strapped to the machine via rubber band.
In order to make the machine draw, the user moves an analog joystick. The changing resistance values of the joystick’s potentiometers are measured by an Arduino. The Arduino then moves each servo to the appropriate position using PWM. If you’d like to know how to do this, check out the Knob Tutorial.
If you’re not ready to l’eggo your Lego drawing machines, check out this super complicated creation or this arm emulator that draws the Mona Lisa.
[Uli Kilian] — best known for solving 100 Rubik’s cubes during the 2011 London Marathon — got addicted to a free iPad game called Jurassic Park builder. Being the efficient man he is, he soon realized the game could be automated — after all, you just have to tap on dinosaurs every few minutes to earn in-game currency…
He’s using a Lego Technic set with an old iPad, and an Arduino connected to a Windows laptop. Wheels roll the iPad back and forth as the robot plays the game. The “finger” of the robot is wrapped in tin-foil and connected to a ground pin to simulate a human finger for the iPad. The article doesn’t explain how it works, but by looking at the robot it appears to just randomly tap away back and forth across the screen — which we guess works for this game?
He hasn’t played with Lego since he was 8, and only just learned about the Arduino a few weeks prior to building this. As a 3D artist he was intrigued to do something in the real-world — nice!
[Thanks Aurelio and William!]