I2C To The Max With ATtiny

January 18, 2022 by 28 Comments

The Arduino is a powerful platform for interfacing with the real world, but it isn’t without limits. One of those hard limits, even for the Arduino MEGA, is a finite number of pins that the microcontroller can use to interface with the real world. If you’re looking to extend the platform’s reach in one of your own projects, though, there are a couple of options available. This project from [Bill] shows us one of those options by using the ATtiny85 to offload some of an Arduino’s tasks using I2C.

I2C has been around since the early 80s as a way for microcontrollers to communicate with each other using a minimum of hardware. All that is needed is to connect the I2C pins of the microcontrollers and provide each with power. This project uses an Arduino as the controller and an arbitrary number of smaller ATtiny85 microcontrollers as targets. Communicating with the smaller device allows the Arduino to focus on more processor-intensive tasks while giving the simpler tasks to the ATtiny. It also greatly simplifies wiring for projects that may be distributed across a distance. [Bill] also standardizes the build with a custom development board for the ATtiny that can also double as a shield for the Arduino, allowing him to easily expand and modify his projects without too much extra soldering.

Using I2C might not be the most novel of innovations, but making it easy to use is certainly a valuable tool to add to the toolbox when limited on GPIO or by other physical constraints. To that end, [Bill] also includes code for an example project that simplifies the setup of one of these devices on the software end as well. If you’re looking for some examples for what to do with I2C, take a look at this thermometer that communicates with I2C or this project which uses multiple sensors daisy-chained together.

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Acid-Damaged Game Boy Restored

January 17, 2022 by 11 Comments

The original Game Boy was the greatest selling handheld video game system of all time, only to be surpassed by one of its successors. It still retains the #2 position by a wide margin, but even so, they’re getting along in years now and finding one in perfect working condition might be harder than you think. What’s more likely is you find one that’s missing components, has a malfunctioning screen, or has had its electronics corroded by the battery acid from a decades-old set of AAs.

That latter situation is where [Taylor] found himself and decided on performing a full restoration on this classic. To get started, he removed all of the components from the damaged area so he could see the paths of the traces. After doing some cleaning of the damage and removing the solder mask, he used 30 gauge wire to bridge the damaged parts of the PCB before repopulating all of the parts back to their rightful locations. A few needed to be replaced, but in the end the Game Boy was restored to its former 90s glory.

This build is an excellent example of what can be done with a finely tipped soldering iron while also being a reminder not to leave AA batteries in any devices for extended periods of time. The AA battery was always a weak point for the original Game Boys, so if you decide you want to get rid of batteries of any kind you can build one that does just that.

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Parsing PNGs Differently

January 17, 2022 by 5 Comments

There are millions of tiny bugs all around us, in everything from our desktop applications to the appliances in the kitchen. Hidden, arbitrary conditions that cause unintended outputs and behaviors. There are many ways to find these bugs, but one way we don’t hear about very often is finding a bug in your own code, only to realize someone else made the same mistake. For example, [David Buchanan] found a bug in his multi-threaded PNG decoder and realized that the Apple PNG decoder had the same bug.

PNG (Portable Network Graphics) is an image format just like JPEG, WEBP, or TIFF designed to replace GIFs. After a header, the rest of the file is entirely chunks. Each chunk is prepended by a four-letter identifier, with a few chunks being critical chunks. The essential sections are IHDR (the header), IDAT (actual image data), PLTE (the palette information), and IEND (the last chunk in the file). Compression is via the DEFLATE method used in zlib, which is inherently serial. If you’re interested, there’s a convenient poster about the format from a great resource we covered a while back.

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People in meeting, with highlights of detected phones and identities

Machine Learning Detects Distracted Politicians

January 17, 2022 by 39 Comments

[Dries Depoorter] has a knack for highly technical projects with a solid artistic bent to them, and this piece is no exception. The Flemish Scrollers is a software system that watches live streamed sessions of the Flemish government, and uses Python and machine learning to identify and highlight politicians who pull out phones and start scrolling. The results? Pushed out live on Twitter and Instagram, naturally. The project started back in July 2021, and has been dutifully running ever since, so by now we expect that holding one’s phone where the camera can see it is probably considered a rookie mistake.

This project can also be considered a good example of how to properly handle confidence in results depending on the application. In this case, false negatives (a politician is using a phone, but the software doesn’t detect it properly) are much more acceptable than false positives (a member gets incorrectly identified, or is wrongly called-out for using a mobile device when they are not.)

Keras, an open-source software library, is used for the object detection and facial recognition (GitHub repository for Keras is here.) We’ve seen it used in everything from bat detection to automatic trash sorting, so if you’re interested in machine learning applications, give it a peek.

AI Camera Knows Its S**t

January 17, 2022 by 13 Comments

[Caleb] shares a problem with most dog owners. Dogs leave their… byproducts…all over your yard. Some people pick it up right away and some just leave it. But what if your dog has run of the yard? How do you know where these piles are hiding? A security camera and AI image detection is the answer, but probably not the way that you think.

You might think as we did that you could train the system to recognize the–um–piles. But instead, [Caleb] elected to have the AI do animal pose estimation to detect the dog’s posture while producing the target. This is probably easier than recognizing a nondescript pile and then it doesn’t matter if it is, say, covered with snow.

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New Part News: Raspberry Pi Cuts Out The Middleman

January 17, 2022 by 36 Comments

Raspberry Pi has just announced that they’ll be selling their RP2040 microcontroller chips by the reel, directly to you, at a decent discount.

About a year ago, Raspberry Pi released its first piece of custom silicon, the RP2040 microcontroller. They’ve have been selling these chips in bulk to selected customers directly, but have decided to open up the same deals to the general public. If you’re looking for 500 chips or more, you can cut out the middleman and save some serious dough.

Because the RP2040 was a clean-slate design, it uses a relatively modern production process that yields many more processors per silicon wafer, and it has been essentially spared from the chip crisis of 2020-2021. According to CEO Eben Upton, they’ve sold 1.5 million in a year, and have wafers in stock for 20 million more. You do the math, but unless you’re predicting the chip shortage to last in excess of 12 years, they’re looking good.

Electromyography

Electromyography Hack Chat

January 17, 2022 by No comments

Join us on Wednesday, January 19 at noon Pacific as we kick off the 2022 Hack Chat season with the Electromyography Hack Chat with hut!

It’s one of the simplest acts most people can perform, but just wiggling your finger is a vastly complex process under the hood. Once you consciously decide to move your digit, a cascade of electrochemical reactions courses from the brain down the spinal cord and along nerves to reach the muscles fibers of the forearm, where still more reactions occur to stimulate the muscle fibers and cause them to contract, setting that finger to wiggling.

join-hack-chatThe electrical activity going on inside you while you’re moving your muscles is actually strong enough to make it to the skin, and is detectable using electromyography, or EMG. But just because a signal exists doesn’t mean it’s trivial to make use of. Teasing a usable signal from one muscle group amidst the noise from everything else going on in a human body can be a chore, but not an insurmountable one, even for the home gamer.

To make EMG a little easier, our host for this Hack Chat, hut, has been hard at work on PsyLink, a line of prototype EMG interfaces that can be used to detect muscle movements and use them to control whatever you want. In this Hack Chat, we’ll dive into EMG in general and PsyLink in particular, and find out how to put our muscles to work for something other than wiggling our fingers.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, January 19 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

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