Author: Kristina Panos

1861 Articles

Homebrew Oscillator Is In A Glass By Itself

September 7, 2019 by 8 Comments

Great things happen when we challenge ourselves. But when someone else says ‘I bet you can’t’ and you manage to pull it off, the reward is even greater. After [WilkoL] successfully made a tuning fork oscillator, his brother challenged him to make one out of a wine glass. We’ll drink to that!

First, [WilkoL] needed to find a way to make the wine glass vibrate continuously without having to stand there running a moistened finger around the edge. A piezo speaker mounted close by did the trick. Then he had to detect the sound waves, amplify them, and feed them back in.

After toying with the idea of making a laser microphone, and tossing aside the idea of a regular microphone (because squealing feedback), he settled on using light. LEDs didn’t work, probably because the light is too divergent. But he found out that by aiming a laser just right, the curve of the wine glass modulates the light, and the waves can be detected with a phototransistor.  Then it was just a matter of amplifying the the sound and feeding it back to the piezo.

In the demo video after the break, you can see the vibrations in the glass manifest once he pours in some water. As anyone who’s ever played the water glasses can tell you, this also changes the frequency. [Editor’s note: I expected a much larger change in pitch. Not sure what’s going on here.]

Speaking of, here’s a steampunky glass armonica that uses an old turntable motor to rotate the wine glass, and a pneumatic cylinder to raise and lower the water level.

Continue reading “Homebrew Oscillator Is In A Glass By Itself” →

Hack Your Brain To Stop Overeating

September 5, 2019 by 30 Comments

Sometimes the easiest advice can be the hardest to follow. For example: if you want to lose weight, you must eat right and exercise. You can avoid both and still lose weight by simply eating less, but that takes willpower.

Losing weight is one of the hardest things a person can do, because we have to eat to survive. That leaves the problem of stopping when we’re full. Here in the united states of high-fat foods and huge portions, that can be really, really difficult, as evidenced by the obesity statistics. But no matter where you live, it’s easy to ignore the ‘stomach full’ signal. It’s kind of slow, anyway. So how do you get yourself tuned into the signal? All it takes is a little classical conditioning.

Slim Band is simple, but effective. Basically, it’s a pack of breath-freshening strips strapped to a timer PCB and set into a watchband. Set the five-minute timer when you start eating, and when it goes off, take out a strip and mintify your mouth. By the time the minty-ness wears off, you should feel full enough to push your plate away. The convenience factor is a big plus—there’s no getting the phone out to set an alarm, or digging for mints in your pocket or purse.

Though the idea began as a personal improvement project, [Chaz] would like to see it widely adopted as a way of fighting obesity and evening out the world’s food distribution in the longer term. We would, too.

The HackadayPrize2019 is Sponsored by:

Kinetic Lamp Sheds Light On Scientific Principles

September 5, 2019 by 7 Comments

This thing right here might be the coolest desk toy since Newton’s Cradle. It’s [Stephen Co]’s latest installment in a line of mesmerizing, zodiac-themed art lamps that started with the water-dancing Aquarius.  All at once, it demonstrates standing waves, persistence of vision, and the stroboscopic effect. And the best part? You can stick your finger in it.

This intriguing lamp is designed to illustrate Pisces, that mythological pair of fish bound by string that represent Aphrodite and her son Eros’ escape from the clutches of Typhon. Here’s what is happening: two 5V DC motors, one running in reverse, are rotating a string at high speeds. The strobing LEDs turn the string into an array of optical illusions depending on the strobing rate, which is controlled with a potentiometer. A second pot sweeps through eleven preset patterns that vary the colors and visual effect. And of course, poking the string will cause interesting interruptions.

The stroboscopic effect hinges on the choice of LED. Those old standby 2812s don’t have a high enough max refresh rate, so [Stephen] sprung for APA102Cs, aka DotStars. Everything is controlled with an Arduino Nano clone. [Stephen] has an active Kickstarter campaign going for Pisces, and one of the rewards is the code and STL files. On the IO page for Pisces, [Stephen] walks us through the cost vs. consumer pricing breakdown.

We love all kinds of lamps around here, from the super-useful to the super-animated.

3D Printer Emission Monitor Quantifies The Stench

September 3, 2019 by 14 Comments

While we don’t yet know the long-term effects of hanging out around 3D printers, it doesn’t take a in-depth study to figure out that their emissions aren’t healthy. What smells toxic usually is toxic. Still, it’s oh-so-fun to linger and watch prints grow into existence, even when we have hundreds or thousands of hours of printing under our belts.

Most of us would agree that ABS stinks worse than PLA, and that’s probably because it releases formaldehyde when melted. PLA could be viewed as slightly less harmful because it has a lower melting point, and more volatile organic compounds (VOCs) are released at higher temperatures. Though we should probably always open a window when printing, human nature is a strong force. We need something to save us from our stubbornness, and [Gary Peng] has the answer: a smart 3D printer emission monitor.

The monitor continually checks the air quality and collects data about VOC emissions. As the VOCs become elevated during printing, the user is notified with visual, audio, and phone notifications. Green means you’re good, yellow means open a window, red means GTFO. There’s a brief demo after the break that also shows the phone interface.

The heart of this monitor is a CCS811 gas sensor, which provides VOC data to a Particle Photon. [Gary] built a simple Blynk interface to handle the alerts and graph historical VOC readings. He’s got the code and STLs available, so let this be the last time you watch something print in blissful semi-ignorance.

Concerned about air quality in general? Here’s a standalone portable monitor designed to quantify the soul-crushing stuffiness of meetings.

Continue reading “3D Printer Emission Monitor Quantifies The Stench” →

A Pocket QWERTY For Arduino And More

September 3, 2019 by 15 Comments

If you want to add a keypad to your Arduino project, the options are pretty limited. There’s that red and blue 4×4 membrane we’ve all seen in password-protected door lock projects, and the phone layout version that does pretty much all the same tricks. Isn’t it time for a full Arduino-compatible keyboard? [ELECTRONOOBS] thinks so.

This 41-button Arduino keyboard PCB is a stepping stone to his next project, a pair of two-way texting machines. (Which is nice, because we were totally going to suggest that). It’s based on that ubiquitous red/blue keypad, but it has a full QWERTY layout. There’s also a shift button that opens up special characters and uppercase, and the addition of return, ok, and send keys puts it over the top. The best part of this keyboard, hands down, is the soft, soundless buttons. Though you trade clicky feedback for comfort, it will be well worth it after a few dozen presses.

The keypad uses an onboard ATMega328P to scan the matrix for button presses, decode them, and send them via UART or I²C to an Arduino. [ELECTRONOOBS] has the PCB files available via Patreon for now, though they will be open in the future. The code is already available for download on his website.

Future plans include an LED to indicate when shift is pressed, and adding the special characters next to the numbers on the silkscreen (whoops!). Be sure to check out the build video after the break.

Want an Arduino-driven keyboard for longer hauls across the alphabet? Saddle up and ride this candy-colored mechanical unicorn.

Continue reading “A Pocket QWERTY For Arduino And More” →

Dian Fossey, Gorilla Girl

September 3, 2019 by 37 Comments

Few people sacrifice themselves as completely as Dian Fossey did for the mountain gorillas of Africa. She fought tirelessly to protect them from poachers, cattle herders, zoo kidnappers, corrupt governments, and tourists. Dian left a comfortable life behind to make the misty slopes of an extinct volcano her home and headquarters. There, she patiently sought out the gorillas, mimicking their facial expressions and actions until they grew curious about her. Eventually, she had their complete trust and friendship, and considered them her family.

Dian spent eighteen years on and off living among the gorillas. She continually risked her health, life, and reputation to raise awareness of their plight and save them from extinction. While the mountain gorilla remains an endangered species, Dian’s research and conservation efforts have greatly contributed to their increased population in the years since her death.

Continue reading “Dian Fossey, Gorilla Girl” →

Vintage Car Radio Now Plays Games And Chiptunes

August 27, 2019 by 16 Comments

[MisterM] seems to specialize in squeezing new electronics into old but good-looking technology. His latest creation focuses on a space-age specimen: an interesting car radio from 1963 that could be pulled out from the dashboard and taken along wherever. The beat goes on, thanks to a shiny built-in speaker on the bottom.

He replaced the non-working radio guts with a Raspberry Pi 3 running RetroPie and a Picade controller board. A Pimoroni Blinkt LED strip behind the radio dial glows a different color for each emulated console, which we think is a nice touch. [MisterM] built this console to play in his workshop, and even made a dock for it. But in a lovely homage to the original radio, it’s self-contained and can be taken to the living room or to a friend’s house. There’s also a USB port for whenever player two is ready to enter. For [MisterM]’s next trick, he’ll be converting an 80s joystick.

We love that [MisterM] repurposed the dials as housings for start and select buttons. As he points out, this keeps them out of the way while he’s wildly working the controls. Just enter the Konami Code to unlock the build video below.

Do you dream of playing Donkey Kong absolutely everywhere? Check out the ultraportable mintyPi 2.0.

Continue reading “Vintage Car Radio Now Plays Games And Chiptunes” →