the PCB without the case on, showing the screen, battery, and removable sensor

2023 Hackaday Prize: A Reusable Plant Monitor

[Ovidiu] cares for their house plants, trying to dial in the perfect soil humidity and light levels. However, many cheap monitors tend to rust after a few weeks of sitting in a damp, slightly acidic environment. By creating a custom plant monitor with a removable probe, not only can [Ovidiu] integrate better with their Home Assistant setup, but it will also be less wasteful.

The build starts with an ESP32-S3, a TP4056 charging circuit, a small e-ink display, and an AHT20 IC for air humidity and temperature. The ESP32 reads the probe using the capacitance measuring devices for touchpads built into the chip. Or course, a 450mAh battery provides a battery life of about 11 days. The probe is just a bare PCB with a connector at the top, making them cheap and easy to swap. They included pads on the probe for a thermistor for reading soil temperature, but this is optional. A handsome 3D-printed case wraps it all up nicely.

Continue reading “2023 Hackaday Prize: A Reusable Plant Monitor”

Tiny Spheres Hiding In Your Display

Liquid crystal and Organic LED displays have revolutionized portable computing. They’re also made of glass. Which presents a problem: How do we get electrical signals from fiberglass circuit boards to the glass displays? The answer is double-sided adhesive tape. But we’re not talking about packing tape here. As [Breakingtaps] explains,  this tape has a trick up its sleeve.

The magic is that the tape conducts only in the vertical plane. Even more so, any two conducting sections of the tape are insulated from each other. How does it do that? Magic beans balls, of course!

The tape and adhesive are insulators. Embedded in the adhesive are tiny spheres. The spheres are made of plastic and coated with metal. When the tape (also known as ACF or Anisotropic Conductive Film) is pressed between a PCB with conductors and glass, a few spheres are squished down between the layers. Electrical signals pass between the squished spheres, allowing an image to be displayed on the glass screen. The final step uses heat and pressure to bond the adhesive and cure it. You can also get the material in paste form if you don’t like the tape.

The system works so well that it can be used for connections from a silicon chip directly to the glass.  This is how many display controllers are mounted right to the module — definitely an improvement on the rubber strips used on LCDs of the past.

Continue reading “Tiny Spheres Hiding In Your Display”

Hackaday Links Column Banner

Hackaday Links: August 20, 2023

In some ways, we’ve become a little jaded when it comes to news from Mars, which almost always has to do with the Ingenuity helicopter completing yet another successful flight. And so it was with the report of flight number 54 — almost. It turns out that the previous flight, which was conducted on July 22, suffered a glitch that cut the flight short by forcing an immediate landing. We had either completely missed that in the news, or NASA wasn’t forthcoming with the news, perhaps until they knew more. But the details of the error are interesting and appear related to a glitch that happened 46 flights before, way back in May of 2021, that involves dropped frames from the video coming from the helicopter’s down-facing navigational camera. When this first cropped up back on flight six, it was only a couple of missed frames that nearly crashed the craft, thanks to confusion between the video stream and the inertial data. Flight engineers updated the aircraft’s software to allow for a little more flexibility with dropped frames, which worked perfectly up until the aborted flight 53.

Continue reading “Hackaday Links: August 20, 2023”

Only 8 Chips Make A CPU

We’re no stranger to homemade CPUs on these pages, but we think that [Jiri Stepanovsky]’s 16-bit serial CPU might be a little special. Why? It has an astonishingly low chip count, with only 8 ICs in total. How on earth does he do it?

While a traditional TTL CPU has a relatively high chip count due to a parallel data bus, registers, and discrete ALU, this one takes a few shortcuts by opting for a one-bit serial bus with serial memory chips and an EPROM serving as a look-up-table ALU. Perhaps the most interesting result of this architecture is that it also allows the CPU to dispense with registers, like the Texas Instruments 16-bit chips back in the day. They all live in memory. You can see it below the break in action, streaming a video to a Nokia-style LCD.

Such a CPU would indeed have been unlikely to have been made back in the day due to the prohibitive cost of buying and programming such a large EPROM. However, old computers like the EDSAC also used a serial data path and mercury delay line memory to manage complexity. But for a solid-state CPU in 2023, we think the design is innovative. We think it would be challenging to reduce the chip count further — and no, we’re not counting designs that use a microcontroller to replicate a block of circuitry; that’s cheating — but we’re sure that somewhere there’s a designer with ideas for slimming the design further.

Continue reading “Only 8 Chips Make A CPU”

A Bubble Machine Built From Scrap

Not every project has to be an AI-powered particle accelerator using lasers. Sometimes simple projects can be very satisfying, and a simple project can be a great gateway to introduce a friend or a child to our hacker ways. That’s why we noticed [Crazy Science’s] bubble machine upcycled from a CD and a water bottle. It isn’t likely to figure in anyone’s Ph.D. dissertation any time soon, but that isn’t the point

Once you see the pictures, you can probably figure out how to build it. For extra points, consider scrounging everything from stuff you already have. We were curious about drilling holes in the CD as we’d imagine they’d crack with an ordinary drill bit. Apparently, a soldering iron will pierce the disk, but we would advise doing that in a well-ventilated area.

Continue reading “A Bubble Machine Built From Scrap”

A series of trapezoidal steel "buckets" attached together to form a metal water wheel. They are arranged around a square center frame that attaches to a hub for the wheel to spin about. The wheel is next to a stream and four people of various ages appear to be talking around it. A cinder block building with a metal roof is in the left background, and an older, yellow stone building is far off in the distance on the right of the image. The landscape is lush, green, and mountainous.

Open Source Waterwheel

Here in the West, power going out is an unusual event. But in more remote regions like the Himalayas, reliable electricity isn’t a given. A group of local craftspeople, researchers, and operators in Nepal have worked together to devise a modular waterwheel system.

Based on a 20-30 cm-wide bucket module consisting of only four galvanized steel components, the wheels can be easily built and deployed using resources and tools that are easy to find anywhere in the world. Current test devices generate between 120 and 1,400 Watts of power, depending on the device’s size.

A software tool was also developed that takes the head and flow rate of a location as inputs to calculate the dimensions of the optimal wheel and expected power output for an installation. This lets communities find ideal sites for power generation and calculate the expected costs.

We’ve covered a few other DIY hydropower setups, from repurposed washing machines to custom scratch builds.

Several video clips of a robot arm manipulating objects in a kitchen environment, demonstrating some of the 12 generalized skills

RoboAgent Gets Its MT-ACT Together

Researchers at Carnegie Mellon University have shared a pre-print paper on generalized robot training within a small “practical data budget.” The team developed a system that breaks movement tasks into 12 “skills” (e.g., pick, place, slide, wipe) that can be combined to create new and complex trajectories within at least somewhat novel scenarios, called MT-ACT: Multi-Task Action Chunking Transformer. The authors write:

Trained merely on 7500 trajectories, we are demonstrating a universal RoboAgent that can exhibit a diverse set of 12 non-trivial manipulation skills (beyond picking/pushing, including articulated object manipulation and object re-orientation) across 38 tasks and can generalize them to 100s of diverse unseen scenarios (involving unseen objects, unseen tasks, and to completely unseen kitchens). RoboAgent can also evolve its capabilities with new experiences.

Continue reading “RoboAgent Gets Its MT-ACT Together”