[Joe Grand’s] Toothbrush Plays Music That Doesn’t Suck

It’s not too exciting that [Joe Grand] has a toothbrush that plays music inside your head. That’s actually a trick that the manufacturer pulled off. It’s that [Joe] gave his toothbrush an SD card slot for music that doesn’t suck.

The victim donor hardware for this project is a toothbrush meant for kids called Tooth Tunes. They’ve been around for years, but unless you’re a kid (or a parent of one) you’ve never heard of them. That’s because they generally play the saccharine sounds of Hannah Montana and the Jonas Brothers which make adults choose cavities over dental health. However, …read more

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Saturday Clock: An 0.000011574Hz ATtiny85 clock

In these times when we try to squeeze out extra clock cycles by adding more cores to our CPUs and by enlisting the aid of GPUs, [Ido Gendel] thought it would be fun to go in the exact opposite direction, supply a clock to the ATtiny85 that cycles only once per day, or at 0.000011574Hz. What application could this have? Well, if he could do it in seven instructions or less, how about turning on an LED at sunset Friday evening, to indicate the start of the Jewish Shabbat (Saturday), and turn it off again at sunset Saturday evening.

Notice …read more

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Tea for Two: A Tiny Tea Timer

The ATtiny85 microcontroller doesn’t have all that much of anything: 8 KB of flash, an 8-bit architecture, and only eight pins (three of which are taken up with power and reset duties). And that’s exactly what makes it a great fit for tiny little projects.

[Mimile]’s Tea Timer has a switch, a button, eight LEDs, and a buzzer. Flip the switch to “set” and button presses run through the desired steeping times. Flip it to “run” and you’re timing. The LEDs blink and the buzzer plays “Tea for Two” in squawky square waves. Wonderful!

But wait, how to control all …read more

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Tiny Morse Code USB Keyboard

We’ve featured quite a few of [mitxela]’s projects here in the past, and many of them have the propensity to be labelled “smallest”. His Morse Code USB Keyboard Mk II adds to that list. It’s a Saturday afternoon project, with a few parts slapped onto a piece of perf-board, that allows using a Morse key as a USB keyboard. This project isn’t new or fresh, but we stumbled across it while trying to figure out a use for a Morse key lying in the author’s bin of parts. You can practise transmitting, by reading text and typing it out on …read more

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Making a Spectrum Analyzer the Wrong Way on an ATtiny85

Everyone’s a critic, but it’s hard to argue with success. And that’s exactly what [agp.cooper] has with his ATtiny85-based spectrum analyzer devices.

The “normal” way to build a spectrum analyzer is to collect a bunch of samples and run a Fast Fourier Transform (FFT) on them all in one shot. As the name implies, the FFT is fast, and the result is the frequency components of the sampled data. [agp.cooper]’s “wrong” way to do it takes the Goertzel algorithm, which is used for detecting the intensity of a particular frequency, and scanning across the frequency range of interest. It’s a …read more

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DIY I2C Devices with ATtiny85

[Pawel] has a weather station, and its nerve-center is a Raspberry Pi. He wanted to include a light sensor but the problem is, the Pi doesn’t have a built-in ADC to read the voltage off the light-dependent resistor that he (presumably) had in his junk box. You can, of course, buy I2C ADC chips and modules, but when you’ve already got a microcontroller that has ADC peripherals on board, why bother?

[Pawel] wired up a tremendously simple circuit, downloaded some I2C slave-mode code, and added an LED for good measure. It’s all up on GitHub if you’re interested.

We’re covering …read more

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How Hot is Your Faucet? What Color is the Water?

How hot is the water coming out of your tap? Knowing that the water in their apartment gets “crazy hot,” redditor [AEvans28] opted to whip up a visual water temperature display to warn them off when things get a bit spicy.

This neat little device is sequestered away inside an Altoids mint tin — an oft-used, multi-purpose case for makers. Inside sits an ATtiny85 microcontroller  — re-calibrated using an Arduino UNO to a more household temperature scale ranging from dark blue to flashing red — with additional room for a switch, while the 10k ohm NTC thermristor and RGB LED …read more

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Hackaday Links: October 30, 2016

Diablo. Mech Warrior. Every LucasArts game. There are reasons to build an old PC, and no, emulation cannot completely capture the experience of playing these old games. [Drygol] set out to create a retro PC and succeeded brilliantly. The built features an old desktop AT case (when is the last time you saw one of them?), a 233MHz Pentium with MMX technology, an ancient PCI video card, and an old ISA Ethernet card (with AUI connector). Incoming upgrades will be an ATI 3D Rage PRO, PCI SoundBlaster, and hopefully Windows 98SE.

Right now, we’re gearing up for the Hackaday Superconference …read more

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Just In Time For Christmas! A DIY Desktop LED Tree

Okay, we haven’t even hit Halloween yet, but if you’re planning some kind of holiday project, now’s a good time to start ordering your parts, especially if you’re designing your own PCB. While there’s no PCB involved, [designer2k2] built a desktop “hollow” Christmas tree using some WS2812 RGB LEDs controlled by a microcontroller and powered by USB.

The board running [designer2k2]’s project is a Digispark, a USB powered board by Digistump which contains an ATtiny85. The LEDs, four different sized NeoPixel rings, plus a single pixel for the top, are connected together using some solid wire which makes for a …read more

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Who Could Resist a Color Coded Clock?

[Luc] wanted to make a clock like no other. He knows that the territory is well-trod, especially in the area of minimalist design. Undeterred, [Luc] came up with a fresh design that uses the resistor color code to display the time. He’s calling it the Nerd’s Ultimate Watch.

It doesn’t get much more minimalist than four RGB LEDs. Each one illuminates in the color that represents the digit in the current time. For instance, I’m typing this sentence at 1:37PM. The clock uses 24-hour time, so let’s call it 13:37. Using resistor color code time, that’s 1, 3, 3, 7, or brown, orange, …read more

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