mRNA badge next to an image of the actual Moderna vaccine nanoparticle.

Celebrate MRNA Vaccine With This Badge That Blinks The Nucleotide Code

August 24, 2021 by Jim Heaney 20 Comments

To celebrate getting his second vaccine dose [Paul Klinger] combined two of our favorite things — blinking lights and wearable tech — to create an awesome mRNA vaccine badge.

The badge, which is designed to be worn like a pendant, will slowly blink through all 4,000 nucleotides of the Moderna vaccine over the course of 10 minutes. Watch the video after the break to see it in action. Don’t worry if you got the Pfizer vaccine, you can use the interface button on the back of the badge to change over to Pfizer’s mRNA sequence instead. There’s even a handy legend on the badge, identifying the lipids in case your microbiology skills are a bit rusty.

On the reverse side of the board, you will find a handful of current limiting resistors, a CR2032 battery holder, and the ATtiny1617 microcontroller that runs everything. To assist in converting the mRNA sequence into LED pulses, [Paul] wrote a Python script that will automatically import the nucleotide string from the standard .fasta file and store each nucleotide in just 2 bits, allowing the entire sequence to fit in the program memory of the microcontroller.

This isn’t [Paul’s] first RNA-related project; he originally developed the aforementioned Python script to compress the entirety of the COVID-19 sequence, containing over 30,000 nucleotides, into program memory for his Virus Blinky project, that we featured last year.

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ATtiny85 on circuit board with 2n2222, pushbutton, usb-c power connector, LED, and speaker.

Custom Compression Squeezes Classic Computer Choruses Into A Tiny Controller

August 19, 2021 by Ryan Flowers 14 Comments

Geeks of a certain vintage will have fond memories of games that were simplistic by today’s standards, but drew one in all the same. Their low fidelity graphics were often complimented by equally low fidelity music being forced through the afterthought of a speaker that inhabited most computers. Despite the technical constraints of the era, these games didn’t just offer gameplay. They told stories, and they were immersive in a way that some would think wouldn’t be relatable to a younger generation.

That didn’t stop [Thanassis Tsiodras] from sharing the classic “The Secret of Monkey Island” with his niece and nephew when they were young. Excited to see his family after a year of separation due to COVID-19, [Thanassis] wanted to give them a handmade gift: The music from “The Secret of Monkey Island” on a custom player. What an uncle!

[Thanassis] could have just recorded the music and played it back using any number of chips made for the purpose, but being a long time software engineer, he decided to take the scenic route to his destination. First, DOSBox was hacked to dump the speaker output into a file. Python, C, and 30 years of experience were leveraged to squeeze everything into the 8 KB storage of an ATtiny85. Doing so was no small feat, as it required that he create a custom implementation of Huffman compression to get the data small enough to fit on chip. And when it fit, but didn’t work, even more optimization was needed.

The end result was worth it however, with the music from “The Secret of Monkey Island” playing in its original form from a speaker driven by the ever so humble but useful 2n2222. [Thanassis]’ site is replete with details too intricate to post here, but too neat to miss. Watch the video below the break for a demonstration.

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DIY Handheld Game Puts Its Brains On A Removable Cart

August 16, 2021 by Tom Nardi 10 Comments

Over the years we’ve seen plenty of homebrew handheld game systems that combine an AVR microcontroller, a few buttons, and an small OLED display. Some of them have even been turned into commercial products, such as the Arduboy. They’re simple, cheap, and with the right software, a lot of fun. But being based on an MCU, most of them share the same limitation of only being able to hold a single game at any one time.

But not the Game Card, by [Dylan Turner]. This handheld was specifically designed so that games could be easily swapped out using physical cartridges. But rather than trying to get the system’s microcontroller to boot code from an external flash chip, the system relocates the MCU to the removable cartridge. That might seem a bit overkill, but given how cheap the ATTINY84A on each cartridge is, it’s not exactly going to break the bank.

With the microcontroller on the cartridge, the only hardware that stays behind on the Game Card is the SSD1306 128×64 OLED display, buttons, and the battery. That means the handheld is effectively non-functional unless a game is slotted in, but that could be said of most early cartridge-based game systems as well. On the other hand, it also opens up the possibility of producing cartridges with more powerful microcontrollers down the line.

Using a different microcontroller for each game is a neat hack, but it’s not the only solution to the problem. We previously saw a community effort to add expandable storage to the Arduboy in the form of a DIY cartridge, which ultimately led to the development of an official flash chip upgrade for the handheld.

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An OLED Photo Frame Powered By The ATtiny85

July 19, 2021 by Tom Nardi 10 Comments

Rolling your own digital picture frame that loads images from an SD card and displays them on an LCD with a modern microcontroller like the ESP32 is an afternoon project, even less if you pull in somebody else’s code. But what if you don’t have the latest and greatest hardware to work with?

Whether you look at it as a practical application or an interesting experiment in wringing more performance out of low-end hardware, [Assad Ebrahim]’s demonstration of displaying digital photographs on an OLED using the ATtiny85 is well worth a look. The whole thing can put put together on a scrap of perfboard with a handful of common components, and can cycle through the five images stored on the chip’s flash memory for up to 20 hours on a CR2032 coin cell.

As you might expect, the biggest challenge in this project is getting all the code and data to fit onto the ATtiny85. To that end [Assad] wrote his own minimal driver for the SSD1306 OLED display, as the traditional Adafruit code took up too much space. The driver is a pretty bare bones implementation, but it’s enough to initialize the screen and get it ready for incoming data. His code also handles emulating I2C over Atmel’s Universal Serial Interface (USI) at an acceptable clip, so long as you bump the chip up to 8 MHz.

For the images, [Assad] details the workflow he uses to take the high-resolution color files and turn them into an array of bytes for the display. Part of that it just scaling down and converting to 1-bit color, but there’s also a bit of custom Forth code in the mix that converts the resulting data into the format his code expects.

This isn’t the first time we’ve seen somebody use one of these common OLED displays in conjunction with the ATtiny85, and it’s interesting to see how their techniques compare. It’s not a combination we’d necessarily chose willingly, but sometimes you’ve got to work with whats available.

A Perfect Clock For Any Hacker’s Ohm

July 15, 2021 by Adam Zeloof 29 Comments

The vast majority of us are satisfied with a standard, base ten display for representing time. Fewer of us like to be a bit old-fashioned and use a dial with a couple of hands that indicate the time, modulo twelve. And an even smaller minority, with a true love for the esoteric, are a fan of binary readouts. Well, there’s a new time-telling game in town, and as far as we’re concerned it’s one of the best ones yet: resistor color codes.

The Ohm Clock is, as you may have guessed, a giant model of a resistor that uses its color bands to represent time. Each of the four bands represents a digit in the standard HH:MM representation of time, and for anybody well-versed in resistor codes this is sure to be a breeze to read. The clock itself was designed by [John Bradnam]. It’s body is 3D printed, with RGB LEDs to brightly illuminate each segment. The whole thing is controlled by an old favorite – an ATtiny, supported by a Real Time Clock (RTC) chip for accurate timekeeping.

You can set the time in the traditional fashion using buttons, or — and here’s the brilliant part — you can use a resistor. Yup, that’s right. Connecting a 220 Ohm resistor across two terminals on the clock will set the time to 2:20. Genius.

When you come across an art as old as timekeeping, it’s easy to assume that everything’s already been done. We have sundials, hourglasses, analog clocks, digital watches, those cool clocks that use words instead of numbers, the list goes on. That’s why it’s so exciting to see a new (and fun!) idea like this one emerge.

An OSHW IR Remote Control Powered By The ATtiny13A

July 2, 2021 by Tom Nardi 15 Comments

The new hotness in consumer electronics might be RF remotes based on protocols like Bluetooth Low Energy, but there’s still plenty of life left in the classic infrared remote. Especially with projects like TinyRemoteXL from [Stefan Wagner], which let you build and program an IR “clicker” of your own. Whether you want to spin up your own custom universal remote or create a beefed up version of the TV-B-Gone, this open source effort is a great place to start.

As you might have guessed from the name, this project is actually a larger version of the TinyRemote that [Stefan] put together previously. The documentation for that project goes a bit more into the nuts and bolts of talking IR, and is definitely worth a read if you’re into the low level stuff. For the original five button TinyRemote, the hardware consists of little more than a ATtiny13A microcontroller, a pair of IR LEDs, and the transistors to drive them.

But on the XL, things are a bit trickier as there are now twelve buttons for the ATtiny13A to read. Obviously there aren’t enough pins to read so many buttons directly, but with a combination of BAS16TW diode arrays and resistors, [Stefan] is able to detect what button was pressed using the chip’s interrupt pin and ADC. Certainly a handy trick to have in the back of your mind, and the open source nature of this project gives you a great chance to see how it’s implemented.

Between this project and the impressive development board [Djordje Mandic] released recently, it seems we’re looking at something of an infrared hacking revival. Earlier this year we even saw the commercial release of an IR-equipped ESP8266 board.

Spectrum Display Uses Tiny CPU And Many LEDs

June 23, 2021 by Al Williams 1 Comment

You would think the hard part about creating a spectrum analyzer using a pint-sized ATTiny85 would be the software. But for [tuenhidiy], we suspect the hard part was fabricating an array of 320 LEDs that the little processor can drive. The design does work though, as you can see in the video below.

The key is to use a TPIC6B595N which is an 8-bit shift register made to drive non-logic outputs. With all outputs on, the driving FETs can supply 150 mA per channel and the device can handle 500 mA per channel peak. At room temperature, the part can go over 1W of total power dissipation, although that goes down with temperature, of course. If you need higher power, there’s a DW-variant of the part that can handle a few hundred milliwatts more.

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