If you have spare pins on your tinyAVR micro you can use them with the CCL for “glue logic” and save on your bill of materials (BOM) cost. The CCL can do simple to moderately complex logic, and it does it without the need for support from the processor core, which is why it’s called a core independent peripheral. A good place to learn about the CCL capabilities in these tinyAVR series is Microchip Technical Brief TB3218: Getting Started with Configurable Custom Logic (CCL) or if you need more information see a datasheet, such as the ATtiny3226 datasheet mentioned in the video.
There’s just something about a satisfying “click” that our world of touchscreens misses out on; the only thing that might be better than a good solid “click” when you hit a button is if device could “click” back in confirmation. [Craig Shultz] and his crew of fine researchers at the Interactive Display Lab at the University of Illinois seem to agree, because they have come up with an ingenious hack to provide haptic feedback using readily-available parts.
An array of shapes showing some of the different possibilities for hapticoil soft buttons.
The “hapticoil”, as they call it, has a simple microspeaker at its heart. We didn’t expect a tiny tweeter to have the oomph to produce haptic feedback, and on its own it doesn’t, as finger pressure stops the vibrations easily. The secret behind the hapticoil is to couple the speaker hydraulically to a silicone membrane. In other words, stick the thing in some water, and let that handle the pressure from a smaller soft button on the silicone membrane. That button can be virtually any shape, as seen here.
Aside from the somewhat sophisticated electronics that allow the speaker coil to be both button and actuator (by measuring inductance changes when pressure is applied, while simultaneously driven as a speaker), there’s nothing here a hacker couldn’t very easily replicate: a microspeaker, a 3D printed enclosure, and a silicone membrane that serves as the face of the haptic “soft button”. That’s not to say we aren’t given enough info replicate the electronics; the researchers are kind enough to provide a circuit diagram in figure eight of their paper.
In the video below, you can see a finger-mounted version used to let a user feel pressing a button in virtual reality, which raises some intriguing possibilities. The technology is also demonstrated on a pen stylus and a remote control.
When was the last time you saw a computer actually outlast your weekend trip – and then some? Enter the Evertop, a portable IBM XT emulator powered by an ESP32 that doesn’t just flirt with low power; it basically lives off the grid. Designed by [ericjenott], hacker with a love for old-school computing and survivalist flair, this machine emulates 1980s PCs, runs DOS, Windows 3.0, and even MINIX, and stays powered for hundreds of hours. It has a built-in solar panel and 20,000mAh of battery, basically making it an old-school dream in a new-school shell.
What makes this build truly outstanding – besides the specs – is how it survives with no access to external power. It sports a 5.83-inch e-ink display that consumes zilch when static, hardware switches to cut off unused peripherals (because why waste power on a serial port you’re not using?), and a solar panel that pulls 700mA in full sun. And you guessed it – yes, it can hibernate to disk and resume where you left off. The Evertop is a tribute to 1980s computing, and a serious tool to gain some traction at remote hacker camps.
For the full breakdown, the original post has everything from firmware details to hibernation circuitry. Whether you’re a retro purist or an off-grid prepper, the Evertop deserves a place on your bench. Check out [ericjenott]’s project on Github here.
Upgrading RAM on most computers is often quite a straightforward task: look up the supported modules, purchase them, push a couple of levers, remove the old, and install the new. However, this project submitted by [Mads Chr. Olesen] is anything but a simple.
In this project, he sets out to double the RAM on a Olimex A20-OLinuXino-LIME2 single-board computer. The Lime2 came with 1 GB of RAM soldered to the board, but he knew the A20 processor could support more and wondered if simply swapping RAM chips could double the capacity. He documents the process of selecting the candidate RAM chip for the swap and walks us through how U-Boot determines the amount of memory present in the system.
While your desktop likely has RAM on removable sticks, the RAM here is soldered to the board. Swapping the chip required learning a new skill: BGA soldering, a non-trivial technique to master. Initially, the soldering didn’t go as planned, requiring extra steps to resolve issues. After reworking the soldering, he successfully installed both new chips. The moment of truth arrived—he booted up the LIME2, and it worked! He now owns the only LIME2 with 2 GB of RAM.
Over on his YouTube channel [Aaron Danner] explains biasing transistors with current sources in the 29th video of his Transistors Series. In this video, he shows how to replace a bias resistor (and consequently an additional capacitor) with a current source for both common-emitter and common-collector amplifiers.
A current source provides electrical energy with a constant current. The implication is that if the resistance of the load changes the current source will vary the voltage to compensate. In reality, this is exactly what you want. The usual resistor biasing arrangement just simulates this over a narrow voltage range, which is generally good enough, but not as good as a true current source.
In this series of 23 YouTube videos [Rich] puts the AMD Zynq-7000 SoC through its paces by building a development board from the ground up to host it along with its peripherals. The Zynq is part FPGA and part CPU, and while it has been around for a while, we don’t see nearly as many projects about it as we’d like.
[Rich] covers everything from the power system to HDMI, USB, DDR RAM, and everything in between. By the end, he’s able to boot PetaLinux.
If you had to guess, what do you think it would take to build an ocean-going buoy that could not only survive on its own without human intervention for more than two years, but return useful data the whole time? You’d probably assume such a feat would require beefy hardware, riding inside an expensive and relatively large watertight vessel of some type — and for good reason, the ocean is an unforgiving environment, and has sent far more robust hardware to the briny depths.
But as Wayne Pavalko found back in 2016, a little planning can go a long way. That’s when he launched the first of what he now calls Maker Buoys: a series of solar-powered drifting buoys that combine a collection of off-the-shelf sensor boards with an Arduino microcontroller and an Iridium Short-Burst Data (SBD) modem in a relatively simple watertight box.
He guessed that first buoy might last a few weeks to a month, but when he finally lost contact with it after 771 days, he realized there was real potential for reducing the cost and complexity of ocean research.
Wayne recalled the origin of his project and updated the audience on where it’s gone from there during his 2024 Supercon talk, Adventures in Ocean Tech: The Maker Buoy Journey. Even if you’re not interested in charting ocean currents with homebrew hardware, his story is an inspirational reminder that sometimes a fresh approach can help solve problems that might at first glance seem insurmountable.
