Gears are fairly straightforward way to couple rotational motion, and the physics topics required to understand them are encountered in an entry level physics classroom, not a university degree. But to really dig down to the root of how gears transfer motion may be somewhat more complex than it seems. [Bartosz Ciechanowski] put together an astonishingly good interactive teaching tool on gears, covering the fundamentals of motion up through multi-stage gear trains.
The post starts at the beginning – not “how to calculate a gear ratio” – but how does rotational motion work at all. The illustrations help give the reader an intuitive sense for how the rate of rotation is measured and what that measurement actually represents in the real world. From there [Bartosz] builds up to describing how two discs touching edge to edge transfer motion and the relationship of their size on that process. After explaining torque he has the fundamentals in place to describe why gears have teeth, and why they work at all.
Well written explanatory copy aside, the real joy in this post is the interactivity. Each concept is illustrated, and each illustration is interactive. Images are accompanied by a slider which lets you adjust what’s shown, either changing the speed of a rotating gear or advancing the motion of two teeth interlocking. We found that being able to move through time this way really helped form an intuitive understanding of the concepts being discussed. This feels like the dream of interactive multimedia textbooks come to life.
Robots have certainly made the world a better place. Virtually everything from automobile assembly to food production uses a robot at some point in the process, not to mention those robots that can clean your house or make your morning coffee. But not every robot needs such a productive purpose. This one allows you to punch the world, which while not producing as much physical value as a welding robot in an assembly line might, certainly seems to have some therapeutic effects at least.
The IoT Planet Puncher comes to us from [8BitsAndAByte] who build lots of different things of equally dubious function. This one allows us to release our frustration on the world by punching it (or rather, a small model of it). A small painted sphere sits in front of a 3D-printed boxing glove mounted on a linear actuator. The linear actuator is driven by a Raspberry Pi. The Pi’s job doesn’t end there, though, as the project also uses a Pi camera to take video of the globe and serve it on a webpage through which anyone can control the punching glove.
The exhibit that [Niklas Roy] came up with is called Wasserorgel, or “water organ”, an apt name for the creation. Built as part of a celebration of industry in Germany, the display was built in the small town of Winnenden, home to Kärcher, a cleaning equipment company best known for their line of pressure washers in the distinctive yellow cases. Eight of the company’s electric pressure washers were featured in the Wasserorgel, which shot streams of water and played notes in response to passersby tickling the sturdy and waterproof 3D-printed keyboard. The show was managed by an Arduino with a MIDI shield, which controlled the pressure washers via solid state relays and even accepted input from an anemometer to shut down the show if it got too windy, lest the nearby [Frau Dimitrakudi] be dampened.
The video below shows how engaging the Wasserorgel was during its weeks-long run in the town market square; there’s also one in German with build details. And while we can’t recall seeing pressure washers in public art before, we do remember one being used as the basis of a DIY water-jet cutter.
[pepelepoisson]’s Miroir Magique (“Magic Mirror”) is an interesting take on the smart mirror concept; it’s intended to be a playful, interactive learning tool for kids who are at an age where language and interactivity are deeply interesting to them, but whose ceaseless demands for examples of spelling and writing can be equally exhausting. Inspiration came from his own five-year-old, who can neither read nor write but nevertheless has a bottomless fascination with the writing and spelling of words, phrases, and numbers.
The magic is all in the simple interface. Magic Mirror waits for activation (a simple pass of the hand over a sensor) then shows that it is listening. Anything it hears, it then displays on the screen and reads back to the user. From an application perspective it’s fairly simple, but what’s interesting is the use of speech-to-text and text-to-speech functions not as a means to an end, but as an end in themselves. A mirror in more ways than one, it listens and repeats back, while writing out what it hears at the same time. For its intended audience of curious children fascinated by the written and spoken aspects of language, it’s part interactive toy and part learning tool.
Like most smart mirror projects the technological elements are all hidden; the screen is behind a one-way mirror, speakers are out of sight, and the only inputs are a gesture sensor and a microphone embedded into the frame. Thus equipped, the mirror can tirelessly humor even the most demanding of curious children.
[pepelepoisson] explains some of the technical aspects on the project page (English translation link here) and all the code and build details are available (in French) on the project’s GitHub repository. Embedded below is a demonstration of the Magic Mirror, first in French then switching to English.
It’s a simple fact that most programs created for the personal computer involve the same methods of interaction, almost regardless of purpose. Word processors, graphics utilities, even games – the vast majority of interaction is performed through a keyboard and mouse. However, sometimes it can be fun to experiment with alternative technologies for users to interact with code – Paper Programs is an exciting way to do just that.
It’s a system that creates a very tactile way of interacting with a program – by moving the page around or placing different pages next to each other, programs can interact in various ways. The system is setup for collaboration as well, allowing users to edit code directly in the browser.
The project reminds us of earlier works on DIY multitouch screens, but with a greater focus on direct engagement with the underlying code. What other unique ways exist to interact with code? Let us know in the comments.
Digital color theory can be a tricky concept to wrap one’s mind around – particularly if you don’t have experience with digital art. The RGB color model is about as straightforward as digital color mixing gets: you simply set the intensity of red, green, and blue individually. The result is the mixing of the three colors, based on their individual intensity and the combined wavelength of all three. However, this still isn’t nearly as intuitive as mixing paint together like you did in elementary school.
To make RGB color theory more tangible, [Tore Knudsen and Justin Daneman] set out to build a system for mixing digital colors in a way that reflects physical paint mixing. Their creation uses three water-filled containers (one each for red, green, and blue) to adjust the color on the screen. The intensity of each color is increased by pouring more water into the corresponding container, and decreased by removing water with a syringe.
An Arduino is used to detect the water levels, and controls what the user sees on the screen. In one mode, the user can experiment with how the color levels affect the way a picture looks. The game mode is even more interesting, with the goal being to mix colors to match a randomly chosen color that is displayed on the screen.
When you already know exactly where and how you’d like your motor to behave, a code-compile-flash-run-debug cycle can work just fine. But if you want to play around with a stepper motor, there’s nothing like a live interface. [BrendaEM]’s RDL is a generic stepper motor driver environment that you can flash into an Arduino. RDL talks to your computer or cell phone over serial, and can command a stepper-driver IC to move the motor in three modes: rotary, divisions of a circle, and linear. (Hence the acronumical name.) Best of all, the entire system is interactive. Have a peek at the video below.
The software has quite a range of capabilities. Typing “?” gets you a list of commands, typing “@” tells you where the motor thinks it is, and “h” moves the motor back to its home position. Rotating by turns, degrees, or to a particular position are simple. It can also read from an analog joystick, which will control the rotation speed forward and backward in real time.
Division mode carves the pie up into a number of slices, and the motor spins to these particular locations. Twelve, or sixty, divisions gives you a clock, for instance. Acceleration and deceleration profiles are built in, but tweakable. You can change microstepping on the fly, and tweak many parameters of the drive, and then save all of the results to EEPROM. If you’re playing around with a new motor, and don’t know how quickly it can accelerate, or what speeds it’s capable of, nothing beats playing around with it interactively.