As described in this project’s write-up, “The brachistochrone curve is a classic physics problem, that derives the fastest path between two points A and B which are at different elevations.” In other words, if you have a ramp leading down to another point, what’s the quickest route?
Intuitively—and incorrectly—you might think this is a straight line, and while you could work out the solution mathematically, this rig releases three marbles at a time, letting them cruise down to the Arduino Uno-based timing mechanism to see which path is fastest.
The ramps are made out of laser-cut acrylic, and the marbles each strike a microswitch to indicate they’ve finished the race. The build looks like a great way to cement a classic physics problem in students’ minds, and learn even more while constructing the contraption!
The device features 36 servo motors arranged on a pegboard to produce various patterns, and can even be used in an interactive mode where it follows a person’s hand around with the help of ultrasonic sensors.
Everything is driven by an Arduino Uno along with three 16-channel PWM control modules, and popsicle sticks show the servo movement to onlookers.
Details, including Arduino code, can be found in the Domke’s write-up. To really appreciate this project’s visuals, be sure to take in the coordinated movements in the video below!
Gray Eldritch (AKA The Technomanc3r) has been working on a robotic hand for some time now, and has settled (so far) on a design with three independent servo-actuated fingers and a thumb. He’s also implemented a wrist assembly to rotate it back and forth, with an Arduino Uno hidden inside for an entirely self-contained gripper unit.
Each of the three fingers is controlled by a single MG996R servo, as is the wrist, while the thumb adds a second SG90 servo to allow it to move on two axes. The fingers are modular, so they can be swapped out as needed, and you even change the thumb position for ambidextrous operation.
It remains to be seen what Eldritch plans to do with the gripper, but it looks brilliant by itself in the video below.
While computer printers are readily available, if you’d like a plotting device that drags a pen, marker, or whatever you need across paper to create images, your options are more limited. To fill this gap, studioprogettiperduti has come up with the d.i.d, or Deep Ink Diver.
This scalable pen plotter uses a frame made out of 3D-printed parts, as well as aluminum extrusion, which could be lengthened to support the size of paper that you need. A timing belt pulls the writing carriage back and forth, while a roller advances the paper.
The materials and electronics used for the plotter are all standard and easy to source. The main frame is made of aluminum extrusion and 3D-printed connections. The motors are all standard NEMA 17 stepper motors and a single SG-90 servo motor. Everything is driven by a cheap Arduino Uno control board that handles the transition from g-code to movement. Furthermore, the software used to create G-code, Inkscape, is open source as well.
When you need a distraction, or perhaps even now, you may turn to tapping on your desk. While a good way to keep your hands active, or pass a few uninteresting seconds, if you want to get serious with your finger drumming, then the “Arduino USB Drum” by creator colonelwatch may be just the thing.
The 3D-printable device hooks onto the edge of the table, and reads taps on its pads with a pair of strain gauges. Signals are amplified and passed along to an Arduino Uno—including tap intensity—which sends MIDI data to a computer via serial.
Artist Jo Fairfax has created automated drawing machines inspired by carefully manicured Japanese rock gardens, AKA zen gardens. The mesmerizing artwork uses magnets and motors that move underneath a bed of iron filings, generating soothing shapes as viewers come near via motion sensor.
An Arduino Uno is utilized for the device, or rather devices, and you can see a square “magnet garden” in the first video below, automatically producing a circular pattern. A (non-square) rectangular garden sketches a sort of snake/wave pattern in the second clip.
The build is reminiscent of sand drawing machines that rotate a metal marble through magnetic force, but does away with a visible source of movement as the filings react directly to the magnetic field as it’s applied.
An Arduino Uno is programmed to set off a mechanism with integrated magnets below the platform of iron filings. each time a viewer approaches the machine, it starts to ‘draw’ and agitate the black particles, moving them around the platforms. Slowly the drawings become three dimensional and the sense of the magnets’ tracing becomes visible.
The charged iron filings create varying geometric clusters that shape the zen gardens. The drawing machines reveal the forces acting on them, imitating grass and sand that react to the natural force of the wind. the gesture of the viewer’s movement that activates the machine coupled with the magnetic power makes the artwork become a dialogue of forces… elegant and subtle, just like a zen garden.