Author: Bryan Cockfield

1868 Articles

Tricking An Air Conditioner Into Cooling

August 31, 2026 by 22 Comments

Modern heat pumps, of which air conditioners are a subset, seem like simple machines in theory. They just move heat from one place to another. But in order to operate efficiently, they need specific temperatures and humidities on either side of the pump or they can behave in non-ideal ways. [GreatScott!] noticed this when his air conditioner worked well during a heatwave, but started acting anemic once the outside air temperature cooled down. At once point it was barely able to bring his indoor house temperature below the temperature outside, and he went on a deep dive to investigate why this would be and then found a way trick his air conditioner into working outside its designed temperature range.

Many things can cause this behavior, and some of them are indicative of malfunctions like low refrigerant levels or problems with the compressor or control circuitry. But [GreatScott!]’s unit is pretty new so it was unlikely to be something like that. To investigate, he built a circuit with a small heater which is paired to the outdoor heat exchanger’s temperature probe, tricking the control circuitry into working in a different mode. With a few temperature sensors inside and outside, this was enough to kick the air conditioner into high gear and start outputting cold air again.

While noting that we aren’t HVAC experts, there are a few things that could cause this. One of which is high indoor humidity which might be likely for Germany in the summer, or the outdoor condenser needing a certain temperature or pressure range to operate efficiently. Whatever the case, [GreatScott!] decided to remove his creation to keep from inadvertently damaging his air conditioner. It is possible, however, to use a bit of machine learning to find out more about why one’s HVAC system isn’t behaving as well as it should.

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USB-C Adapted For Legacy Sprinkler Systems

August 31, 2026 by 42 Comments

In the modern world USB has become a truly universal connector, with its inclusion on almost every major piece of consumer electronics. It has even expanded well beyond things that we’d think of as consumer electronics, like the solenoids on automatic sprinkler systems.

This project comes to us from [Ray Wang] at opensprinkler.org who has been working on various ways of controlling the old sprinkler standards, which generally rely on a 24 VAC power supply to drive solenoids. This tests uses the power available from USB-PD and closely examines four methods of energizing the solenoids: unipolar PWM, dual voltage, synthesizing an AC wave from a DC supply, and producing a bipolar square wave. The bipolar square wave had some interesting results, being able to get pretty close to the behavior of a true sine wave while minimizing the dedrmand on power electronics.

For those working on old sprinkler systems, or many other antiquated systems that still rely on 24 VAC, this project shows that USB can deliver a surprising amount of power in unique ways, and the fact that it’s near-ubiquitous and affordable makes it that much easier to adapt into situations it was never really designed for.

These old sprinkler systems have other ways of working on modern systems as well, like this one which replaces the AC source for a DC one, but with a few caveats.

LLM Moats Quickly Evaporating

August 30, 2026 by 53 Comments

In the business world, a moat is a quality of a business that makes it difficult for competitors to take that company’s profits. With how hard it is to train models for large language models (LLMs) and generative AI, it might seem like Anthropic, Open AI, and other LLM companies would have huge moats given the amount of compute it takes to build models. But open source models are quickly draining that moat, and now the only thing standing in the way of a customer using one of these models on their own hardware instead one from the larger companies is physical computing resources. [TerminalBytes] demonstrates a few of these models on personally owned computers to show the current state of the art.

[TerminalBytes] started off running the 27B version of the Qwen3.8 on a Mac Studio with 256 GB of unified RAM, which is plenty for this task. But it’s also enough to benchmark a few different models. Qwen3.6 is compared to 3.8, and then the different quants of each model are also compared. Quants are compressed versions of models that need fewer bits to store weights, meaning that the same models can run in less memory with smaller losses in fidelity. Many of these quants run on machines with 32 GB of RAM or less, encompassing many average gaming PCs. There’s even a 1-bit quant that [TerminalBytes] tested which can easily run on a machine with 16 GB, although with mixed results.

Keep in mind that this is just the current state of affairs with open LLMs. Future versions of these models are likely to optimize the number of tokens produced per unit time, or otherwise increase quality of responses while requiring less computer resources. We don’t really think that the ease of running local models will be the sole reason that the AI bubble pops, though. The fact that not every computer user is running Linux is proof enough of that.

Woodstove Assistant Keeps The Heat On Safely

August 30, 2026 by 3 Comments

Those who have never lived in a cold climate might romanticize winters around a fire, keeping warm under blankets while snow gently falls outside. While it certainly can be a cozy experience, using a woodstove comes with a number of pitfalls, and when operated improperly can even cause house-destroying chimney fires. Modern stoves operated properly with properly dried wood make this possibility extremely remote, but it’s still worth keeping an eye on. Reddit user [nas886] built a system called Oru which takes a lot of the guesswork out using one of these pieces of heating equipment.

The real danger of a woodstove isn’t necessarily running the fire too hot, although that can be a problem, but running it too cold. Without full combustion of the wood, flammable creosote builds up on the inside of the chimney which eventually can combust. This system uses a probe placed in the stovepipe to monitor the temperature of the exhaust gasses. If it’s too low an ESP32 notifies [nas886] remotely with with a status LED inside a seperate custom-built walnut enclosure so that more wood can quickly be added or airflow increased to bring up the temperature, and in the case that the fire gets too hot the LED changes to a different color and the air can be closed off a bit.

Woodstoves themselves have quite a bit of variability in the size wood they can burn, the amount they can hold at once, their efficiency, and their thermal mass, so this could find utility for anyone from those with tiny stoves that have to be fed constantly to those trying to get all-night burns in massive units, all without having to constantly sit by the fire and monitor it. [nas886] found initial success selling a few of these custom units and plans to put it into further production as well, but the general idea is not too difficult to replicate for most of us here either.

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Fat Tire Brakes Get Wireless Upgrade

August 29, 2026 by 50 Comments

At first glance, wireless brakes seem like a recipe for disaster. For something as critical as braking, many bicyclists might prefer a physical connection to their method of safely controlling speed. But there are a number of surprising benefits of electronic or wireless braking systems. For one, they can enable systems like anti-lock braking systems and for another they can eliminate cabling or hydraulics on a bicycle. For these reasons, and just for the thrill of it, [Berm Peak] built a set of wireless brakes for his fat tire bicycle to test out the possibilities.

The system uses a set of ESP32 microcontrollers to handle inputs from the braking lever and outputs to the front and rear brakes, as well as a central control unit and display. The brakes themselves are controlled by actuators from car door locks, which when combined with the springs from the stock calipers work to apply a wide range of braking force to the wheels. These did take a bit of prototyping to get working right, by changing to higher quality calipers, increasing the angle of the actuator, and adding longer levers, but eventually a working braking system started to appear.

But replacing a hydraulic system with an electronic one isn’t where something like this shines. [Berm Peak] was able to add in a number of features impossible in traditional braking systems. Not only does this have an ABS system and the possibility to remotely slow down his children’s bikes when they’re riding, but there’s also a braking equalizer that allows the rider to control how much braking there is at certain positions of the brake lever, and another setting called “derp” which doesn’t engage the brakes at all until a certain threshold has passed. This might end up being the next big trend in mountain biking, unlike airless tires.

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Motorized Planer Height Adjustment Dials In

August 29, 2026 by 4 Comments

Having access to a planer opens up a lot of options for woodworking. It enables a craftsman to work with much rougher lumber and the finished results generally have tighter tolerances. But as [DendroLabsDev] found out, the height adjustment wheel on a planer needs a lot of turns to go from its lowest to highest position, and this gets tiresome when greasing parts during maintenance. So what started as a quick hack to quickly perform this single maintenance task eventually resulted in this programmable height adjustment that’s in use on the planer full-time now.

The motor attached to the height adjustment for the planer is a stepper motor, capable of around 1000 steps per inch. Since revolutions on this tool with the stock wheel adjust only a small amount per revolution, this can in theory enable very small tolerances to be dialed in consistently. Not only that, but [DendroLabsDev] has programmed it with a few different modes, the first of which allows a board to be planed to a certain thickness by making several passes, mimicking the workflow of a human-controlled machine. Then a device to zero the position was added, and then the ability to save the height adjustments to make replication across different boards was added, and then a mode to step through set amounts per pass.

What [DendroLabsDev] has essentially made is a high-dollar planer control that is actually available in the most expensive planers, but adapted for a DeWalt planer easily available and semi-affordable at many local hardware stores. It is also theoretically adaptable for any planer with an adjustment wheel, and [DendroLabsDev] has some plans to improve the control system and package it with a PCB and enclosure that would allow it to be a more accessible product for other woodworkers. Adding electronics to woodworking tools other than routers is a popular pastime, take this CNC-controlled scroll saw for example.

3D Printed Piano Action Faithful To The Original

August 29, 2026 by 12 Comments

A piano’s internal mechanism for translating a key press into sound is surprisingly complicated. It has to do a lot of things simultaneously and quickly: provide precise control over velocity, ensure the hammer doesn’t press itself against the strings,  ensure the hammer rebounds without accidentally hitting the strings, allow for quick, continued strikes of the strings, and dampen the string after the key is released. Not only is that a mouthful to say, it’s a tall order for a mechanical device and took (arguably) around 150 years for the idea to be refined into what most of us would recognize as a piano. But could [dovetail] do it with a 3D printer in a few weeks?

[dovetail]’s design relies on compliant mechanisms, which are solid parts that flex in specific and controlled ways to provide movement. The action took many iterations to make sure that all of the feelings of all the parts of a real piano action were accounted for in this model. Pianos have more than one key, though, so [dovetail] also had to design a modular system to piece all the keys together. The modularity extends to the piano’s electronics as well, with a set of PCBs daisy-chained together, each of which supports a set of keys. This is a hybrid piano, a style with a real action but digital sound production. Using infrared sensors allows the instrument to behave as a MIDI keyboard, but one with the goal of feeling somewhere between a digital piano and a fully analog one.

The piano was first demonstrated at Open Sauce, where a number of musicians were able to try it out. As a prototype device it still has a few rough edges that [dovetail] plans to improve upon, like changing the sensors from IR to hall effect, improving the action and using a different filament. There are some other things he has planned as well which we look forward to seeing in future videos. And, although a completely different instrument, it has a number of similarities to this action built to strike a bass drum instead.

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