AVR Multi-Tool Learns The Latest Tricks

Like many of us who fiddle with microcontrollers, [Mike] and [Brian] often found themselves using an ISP programmer and a USB-to-serial adapter. But when they started working on the latest generation of ATtiny chips, they found themselves in need of a Unified Program, and Debug Interface (UPDI) programmer as well. So they decided to wrap all three functions into one handy open hardware gadget.

They call their creation the AVR General Purpose Programmer, or AVRgpp for short. It runs on an ATmega328P with a Pro Mini bootloader, which means that the programmer itself is fully compatible with the Arduino IDE. USB-to-serial capability is provided by a CH330N, and a MC14053 digital switch IC is used to select between talking to the AVRgpp’s onboard MCU or the target device.

A 128 x 32 I2C OLED and two push buttons are used to select the device’s current mode, and there’s a physical switch to select between 5 V or 3.3 V power for the target. There’s also a ST662 12 V regulator, as UPDI targets occasionally need a high voltage pulse to switch into programming mode. Everything is packaged up in a pocket-sized laser cut enclosure that you can easily toss in your bag.

[Mike] and [Brian] say they are considering putting the AVRgpp into small scale production if there’s enough interest, so let them know if you’d like to get one without having to build it yourself.

Flexible PCB Earrings Put The Art In Art Deco

Earrings have been a hackers’ target for electronic attachment for quite a while, but combining the needed components into a package small enough to wear in that finicky location is quite a challenge. If [Sawaiz Syed]’s Art Deco Earrings are anything to go by, ear computers have a bright future ahead of them!

This is a project unusually well described by its name. It is in fact an earring, with art deco styling. But that sells it way too short. This sliver of a flex circuit board is double sided to host an ATtiny, accelerometer, LDO, and eight 2020 formfactor controller-integrated LEDs. Of course it’s motion sensitive, reacting to the wearer’s movement via LED pattern. [Sawaiz] makes reference to wearing it while dancing, and we can’t help but imagine an entire ballroom all aglow with tiny points of LED light.

The Art Deco Earrings are also set apart by the thoroughness of their documentation (have we mentioned how much we love detailed documentation?). [Sawaiz] not only drops the source in your lap, but the README in the Github repo linked at the top walks the reader through each component of the design in detail. Plus the PCBA render is so complete it includes a model of the wire loop to fit through the wearer’s ear; how cool is that? The single piece that’s still in progress is the battery. The earring itself hosts an LDO, so all that is required is stashing a battery somewhere discrete, perhaps in the user’s hair? We’re looking forward to seeing what [Sawaiz] works out.

For the full effect, check out the gif of an assembled unit in action after the break.

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The ATtiny Series Is A Great Companion In Isolation

As a consequence of the social distancing and self isolation, many a maker has been searching for ways to cure boredom. So what happens when you put a maker in a closed space with electronics parts. The answer is a bunch of random microcontroller projects that help beat boredom. [Danac1886] posts a video with a bunch of experiments with the ATtiny series of microcontrollers which can be a source of time-killing inspiration for these tough days of solitude.

The video is based upon a variety of controllers ranging from the ATtiny85 to the ATtiny84 and even includes the ATtiny2313. There is also a project with the ATtiny10, an SMD SOT23-6 package that is quite amazing to behold. All the devices can be programmed using the Ardino as an ISP so all you need is another Arduino lying around in case you do not have an AVR ICSP.

As for the projects themselves, there is an assortment of things that start with the basic blinking LED, adding an I2C LCD and then moving on to a 7 segment display counting up with variable speed controlled with a pot. We really loved how much these tiny projects inspire and can help someone get started with basic electronics and programming.

If you are looking to get started, have a look at the Jumbo LED with the Attiny10 and we assure you, it will brighten your day.

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USB Password Keeper Runs On Tiny Chip

The most important rule of password use, especially when used for online logins, is to avoid reusing passwords. From there, one’s method of keeping track of multiple passwords can vary considerably. While memorization is an option in theory, in practice a lot of people make use of a password manager like Lastpass or KeePass. For those with increased security concerns, though, you may want to implement a USB password keeper like this one based on an ATtiny.

This password keeper, called “snopf”, is a USB device with an ATtiny85 which adds a layer of separation to password keeping that increases security substantially. Passwords are created by the USB device itself using a 128-bit key to generate the passwords, which are physically detached from the computer. Password requests are made by the computer to the USB device, but the user must push a button on the snopf in order to send the password to the computer. It does this by emulating a keyboard, keeping the password information off of the computer’s clipboard.

Of course, snopf isn’t perfectly secure, and the project’s creator [Hajo] goes into detail on the project’s page about some of the potential vulnerabilities. For most use cases, though, none of these are of serious concern. Upgrading your password keeper to a physical device is likely to be a huge security improvement regardless, and one was actually developed on Hackaday a few years ago.

Vinyl Cut Your Way Into An Edge-Lit Glass Display

The chances are you’ve seen the myriad cheap copyright-infringing edge-lit acrylic displays from Chinese suppliers everywhere on the internet, and indeed, etching acrylic with a modest CNC laser cutter has become easily viable to a lot of us in more recent years. However, if you want to kick things up a notch, [Michael Vieau] shows us how to build a plaque from scratch using not acrylic, but rather etched glass to make the finished product look that much more professional.

There are a few different steps to this build and each one is beautifully detailed for anyone who wants to follow along. First, the electronics driving the WS2812 lights are designed from scratch based on an ATtiny microcontroller on a PCB designed in Fritzing, and the sources necessary for replicating those at home are all available on [Michael’s] GitHub. He even notes how he custom-built a pogo-pin header at the end of the USBASP programmer to be able to easily use the same ICSP pinout in future projects.

But since a lot of you are likely all too familiar with the ins and outs of your basic Arduino projects, you’ll be more interested in the next steps, detailing how he milled the solid wood base and etched the glass that fits onto it. The process is actually surprisingly simple, all you need is to mask out the design you want through the use of a vinyl cutter and then pouring some etching solution over it. [Michael] recommends double-etching the design for a crisper look, and putting everything together is just as simple with his fastener of choice: hot glue.

Much as there was an age when Nixie displays adorned every piece of equipment, it seems like ease of manufacture is veering us towards an age of edge-lit displays. From word clocks to pendants and badges, we’re delighted to see this style of decoration emerge, including in replacing Nixies themselves!

Tiny Machine Learning On The Attiny85

We tend to think that the lowest point of entry for machine learning  (ML) is on a Raspberry Pi, which it definitely is not. [EloquentArduino] has been pushing the limits to the low end of the scale, and managed to get a basic classification model running on the ATtiny85.

Using his experience of running ML models on an old Arduino Nano, he had created a generator that can export C code from a scikit-learn. He tried using this generator to compile a support-vector colour classifier for the ATtiny85, but ran into a problem with the Arduino ATtiny85 compiler not supporting a variadic function used by the generator. Fortunately he had already experimented with an alternative approach that uses a non-variadic function, so he was able to dust that off and get it working. The classifier accepts inputs from an RGB sensor to identify a set of objects by colour. The model ended up easily fitting into the capabilities of the diminutive ATtiny85, using only 41% of the available flash and 4% of the available ram.

It’s important to note what [EloquentArduino] isn’t doing here: running an artificial neural network. They’re just too inefficient in terms of memory and computation time to fit on an ATtiny. But neural nets aren’t the only game in town, and if your task is classifying something based on a few inputs, like reading a gesture from accelerometer data, or naming a color from a color sensor, the approach here will serve you well. We wonder if this wouldn’t be a good solution to the pesky problem of identifying bats by their calls.

We really like how approachable machine learning has become and if you’re keen to give ML a go, have a look at the rest of the EloquentArduino blog, it’s a small goldmine.

We’re getting more and more machine learning related hacks, like basic ML on an Arduino Uno, and Lego sortings using ML on a Raspberry Pi.

Parallel Pis For Production Programming; Cutting Minutes And Dollars Off Of Assembly

Assembly lines for electronics products are complicated beasts, often composed of many custom tools and fixtures. Typically a microcontroller must be programmed with firmware, and the circuit board tested before assembly into the enclosure, followed by functional testing afterwards before putting it in a box. These test platforms can be very expensive, easily into the tens of thousands of dollars. Instead, this project uses a set of 12 Raspberry Pi Zero Ws in parallel to program, test, and configure up to 12 units at once before moving on to the next stage in assembly.

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