attiny85

176 Articles

Ambitious ATtiny85 Board Tests A Beginner’s Skills

June 26, 2017 by 31 Comments

[Chris O’Riley] has been playing around with Arduinos for around a year, and decided he wanted a breadboardable ATtiny85 in order to prototype using the actual controller that would be used in the final project. He wants to use it to interface with a Bosch BMP280 pressure sensor, but for now it stands alone.

It’s a simple board with the Tiny85, 3.3 V and 5 V regulators, a power LED, as well as the usual resistors and caps [Ed: not resistor sand caps]. The double-sided PCB [Chris] milled himself — he’s an illustrator and photographer by day, so it’s no surprise the board turned out gorgeous. He designed the board in Illustrator after taking a stab at Eagle, then ran it through his CNC to mill the circuits using a .017 inch end mill as well as drilling the vias. He add solder paste using the tip of a knife, but after messing around with an iron, he ended up investing in a hot air rework station.

We love our Tiny85s here on Hackaday. Check out the ATtiny85 gaming console, the NTSC-generating ATTiny85, and making DIY I2C devices with the chip.

Antique Pinball Machine Lives As Clock

June 3, 2017 by 10 Comments

A big problem with restoring old arcade or pinball machines is finding original parts to get them running again. That’s part of the fun, though; when something finally works after weeks or months of effort. On the other hand, sometimes the only hope for old parts that will never be in a pinball machine again is for [Randy] to come across them. One of those parts he had lying around was a backglass for an old machine, and decided to turn it into a unique word clock.

The original pinball machine was built in 1956, and despite its age the backglass had almost no signs of wear or damage. There are 43 lights on this particular machine which is more than enough for 12 hours, minutes (by the 10s), seconds, and a few extras. An ATtiny85 serves as the controller and drives a fleet of Neopixels hidden in the display. There are also three buttons which control the brightness and allow the time to be set.

Be sure to check out the video below of this one-of-a-kind clock in action. A lot more went into this build as well including framing the glass, giving it a coat of paint and polish, and programming the clock into the microcontroller. Old backglasses from pinball machines seem to be relatively popular to repurpose into more conventional clocks, too, even clocks of an atomic nature.

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Copper Foil Makes Music–With A Little Help

May 2, 2017 by 14 Comments

Craft stores are often the source of odd inspiration. In the stained glass section, we’ve seen the copper foil, and even used it to prototype some RF circuits on the tops of shoeboxes. However, we could never get a good method for connecting ICs to the relatively thick foil. [Bryan Cera] did it though. His paperSynth uses some paper and cardboard for a substrate, copper foil, and an ATtiny CPU to make music. You can see the device in operation in the video, below.

The copper foil is sticky and it isn’t conductive on the back, so anywhere the foil is supposed to touch, you need a blob of solder. We wouldn’t trust the insulation by itself to cross wires, but with a bit of insulating material between–a piece of paper or electrical tape, for example–you could probably cross with impunity. For an RF circuit, you might even make low-value capacitors like that.

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Hackaday Prize Entry: Breathe Your Troubles Away

April 14, 2017 by 13 Comments

Navy SEALs and other highly trained special forces operators all know a simple, basic fact – you’ve got to breathe to live. That seems self-evident, but breathing control is immensely important to being able to perform at a high level in stressful situations. But even if you never anticipate being under fire, you can learn the SEAL way of breathing with this visual aid.

Lest you think that Box Breathing, also known as the four-square breathing technique, is some sort of New Age nonsense, recent research has uncovered the neurological basis for the feeling of calm that can come over someone taking slow, deep, even breaths. But in the heat of the moment, remembering to square your breaths can be a little difficult. [Lim Han Yang] decided that a portable visual cue could help, so he put an ATTiny85, an LED, and a coin cell battery on a tiny circular PCB and spun up a simple translucent dome out of PLA. The blue LED has a soothing appearance behind the diffuser as it goes through a 16-second cycle, ramping up in brightness for four seconds, holding steady for four, then dimming and finally staying dark. The idea is to breathe in sync with the light to get relief from stress.

No build files are posted yet, but we hope to see them soon – we can think of a few people this would benefit greatly. In the meantime, if you’re still looking for that New Age breathing experience, you can always breathe with the psychedelic flowers.

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

March 27, 2017 by 40 Comments

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, we’re inclined to brush the enamel right off of our teeth if we can listen to The Amp Hour, Embedded FM, or the Spark Gap while doing so. Yes, we’re advocating for a bone-conducting, podcasting toothbrush.

[Joe’s] hack starts by cracking open the neck of the brush to cut the wires going to a transducer behind the brushes (his first attempt is ugly but the final process is clean and minimal). This allows him to pull out the guts from the sealed battery compartment in the handle. In true [Grand] fashion he rolled a replacement PCB that fits in the original footprint, adding an SD card and replacing the original microcontroller with an ATtiny85. He goes the extra mile of making this hack a polished work by also designing in an On/Off controller (MAX16054) which delivers the tiny standby current needed to prevent the batteries from going flat in the medicine cabinet.

Check out his video showcasing the hack below. You don’t get an audio demo because you have to press the thing against the bones in your skull to hear it. The OEM meant for this to press against your teeth, but now we want to play with them for our own hacks. Baseball cap headphones via bone conduction? Maybe.

Update: [Joe] wrote in to tell us he published a demonstration of the audio. It uses a metal box as a sounding chamber in place of the bones in our head.

Continue reading “[Joe Grand’s] Toothbrush Plays Music That Doesn’t Suck” →

Saturday clock - 1 CPU clock cycle per day

Saturday Clock: An 0.000011574Hz ATtiny85 Clock

March 21, 2017 by 40 Comments

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 the subtlety. A clock that cycles once per day means you can execute at most one instruction per day. Luckily on AVR microcontrollers, the instructions he needed can execute in just one cycle. That of course meant diving down into assembly code. [Ido] wasn’t an assembly wizard, so to find the instructions, he compiled C code and examined the resulting assembly until he found what he needed. One instruction turns on the LED and the instruction immediately following turns it off again, which normally would make it happen too fast for the human eye to register. But the instruction to turn it on runs on Friday evening and the very next instruction, the one that turns it off, doesn’t run until Saturday evening. Do you feel like you’re in a science fiction story watching time slowed down? Freaky. A few NOPs and the jump for the loop take up the remaining five cycles for the week.

For the source of the clock he chose to use an LDR to detect when the light level dropped at the end of the day. The problem he immediately ran into was that clouds, bird shadows, and so on, also cause drops in the light level. The solution he found was to widen the light and dark range by adding a TLV3702 push-pull output comparator and some resistors. [Ido] gives a detailed explanation of the circuit in the video after the break.

Continue reading “Saturday Clock: An 0.000011574Hz ATtiny85 Clock” →

Tea For Two: A Tiny Tea Timer

March 11, 2017 by 11 Comments

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 of this I/O with just five pins? With one pin each for the two switches and one for the buzzer, that leaves only two pins for the eight LED display. [Mimile]’s fun solution is to use a binary counter (a 74HC393) and the remaining two lines to count and reset. That means toggling a pin very fast 255 times to light up all the LEDs. That’s a bizarre way to go, but we like it!

Hackaday has proven unable to resist the siren song of the ATtiny85. Whether teaching it to swear, to speak I2C, or to transmit analog TV signals, there’s just something about this cute little chip that invites you to test your mettle.