Crowdsourcing An Investigation Into Coil Whine

September 1, 2026 by 2 Comments

If you’ve heard the high-pitched whine or buzz from an electronic device when a current-carrying inductor is vibrating, you’ll know how unpleasant it can be. It’s common in all kinds of equipment, but it’s become a particular annoyance of late in hardware like PC power supplies, GPUs, and cooling pumps. There is plenty of hearsay on the web about which parts whine and which don’t, and [Lowell Wood] wants to get to the bottom of it. 

To track the issue, [Lowell] has put together the Coil Whine Database. It accepts user reports on hardware, regarding the level at which coil whine is present. A score of 0 is given to a part that is inaudible in a quiet room, with higher scores representing higher sound levels. A part scored at 2 is audible working at a desk with the computer under load; a part scored at 4 is audible even when the machine or device is at idle.

For now, the database is largely empty—[Lowell] has just opened submissions, adding a report on their own ROG Astral RTX 5080 card for good measure. If you want to submit a report on a unit, either silent or noisy, that’s simple enough—just fill in the coil whine report form. Over time, submissions will hopefully grow, and it will be easier to get a good idea of what equipment whines and what is likely to operate silently out of the box.

The database aims to present a guide to what parts whine, and how much, noting that any given population of devices tends to vary. To that end, any given device won’t be reported on publicly until it receives at least 5 reports. To counter bias, reports of silent parts will be weighted higher, since it’s unlikely that people happy with their quiet hardware will be rushing to research this issue or report it to a database. Relevant files to the project are available on GitHub for the curious.

This database could be a great boon to the brigade of PC builders out there who like their machines to be as silent as possible. If that sort of thing appeals to you, it’s probably time you started researching passive cooling as well…

open task light

Sliding Into Perfection: The Open Task Light

September 1, 2026 by 5 Comments

A few years ago Dyson released a desk lamp that could slide up and down, in and out, balancing itself at every position. [Steven Bennett] saw that lamp and wanted to make his own. From this passion, the Open Task Light was born.

We covered the prototype of the Open Task Light back in 2023, and the project is a superb example of iteration. In his 15-part video series on the lamp, you can watch him take on each new aspect of the light, improving the mechanisms, electronics, and production. All those small changes add up to this beautifully finished product.

The first thing you’ll notice about the lamp is how little there is to notice: just a pair of extruded aluminum rails with a lamp head on one end and some rollers in the middle. Look a little closer at the rail and you’ll find a PCB running its length, feeding the lamp through pogo pins and leaving no exposed wires. The lamp uses a heat pipe to dump the LED’s heat, again hidden inside the aluminum extrusion. An ESP32 talks to a dedicated LED driver that runs a Cree high-CRI LED. The base comes in several variations for freestanding use or clamping to a table, and it rides on bearings so it can rotate as freely as the lamp’s other axes of movement.

The original lamp this was inspired by carries a hefty price tag, and while the 50-plus-part BOM on this one adds up, it still comes in at well under half the price of its inspiration. The best part: the Open Task Light is open. You can make it your own, head over to [Steven Bennett]’s GitHub to check out the parts. He has also published a well-documented guide on assembling the Open Task Light.

Given the incredible work [Steven] has put into his lamp, we can’t wait to see his next passion project.

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Tricking An Air Conditioner Into Cooling

August 31, 2026 by 5 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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ReactOS Gets An Upgrade

August 31, 2026 by 6 Comments

A perennial in the esoteric operating system space is ReactOS, a project with its roots in the 1990s which is doing a pretty good job of creating an open source clone of 32-bit Windows. They have a new version out, and it’s acquired some useful features.

Top of the list is a new graphical installer, removing the need for separate live and install ISOs, followed by improvements in video bug fixes and high definition audio drivers and subsystems. There’s a headless server install too, in which the GUI is suppressed. Perhaps most interesting, they are working on version syncing the open-source projects such as WINE on which they rely, meaning with luck that any improvements there will show up in ReactOS.

A while back we took a look at using ReactOS as a daily, and found it to be quirks aside, as usable as you’rd expect a Windows XP clone to be. Given that there are plenty of pieces of hardware and software around that still need an early-2000s era Windows to run, this remains an OS to keep an eye on.

Fixing An Expensive Amprobe Cable Tracer With Mystery Fault

August 31, 2026 by 11 Comments

Perhaps the most annoying kinds of faults are those that involve expensive equipment that just sit around in a cupboard, only for them to just stop working at all. Such was the case with the £2,000 Amprobe cable trace kit that [Tom] bought for work-related purposes. After sitting around unused for a few years, the signal generating part of the kit refused to power up at all, with Fluke’s service department wanting at least £600 to even attempt a repair after already having had [Tom] cough up £70 to even get this quote.

Subsequently he instead sent it to [Buy it Fix it] on YouTube for an attempted repair, which at the very least would be a less costly option. These systems use a signal generator connected to the cable, with a separate detector wirelessly tracking this signal. By itself that doesn’t sound too complex, but as it turns out it wasn’t quite so straightforward to diagnose.

After eliminating a basic power or display issue, the SoC’s boot sequence was traced, including reading from the 128 MB NAND Flash. At first glance the unit appeared to be trying to boot and work as normal, which was confirmed after finding a serial port and seeing the log output on it. This showed that the NAND Flash’s boot image failed validation due to apparent corruption.

After desoldering the TSOP 48 Flash package and stuffing it into a reader, at first glance the data on it looked fine. After a tragic detour with Google’s Gemini chatbot that led to a lot of wasted time, the solution that the human intelligence came up with was to crack open the tracer unit in the set and ogle at its firmware, in particular the bootloader.

Comparing the two Flash dump files, there were a few flipped bits in the bootloader section, likely due to cells in the Flash having lost their charge. Writing the generator’s Flash with a corrected image led to it booting up happily again into the Linux 2.6-based firmware, seemingly no worse for wear. Of course, one has to consider here that the NAND Flash IC clearly has a few leaky cells in it, so replacing it with a fresh one could be a good idea for a long-term fix.

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Building An Energy-Harvesting Business Card

August 31, 2026 by 2 Comments

The hope is always that a good business card will leave a good impression. For those in the electronics field, they also serve as an opportunity to showcase creative design skills. [Wilson Harper] demonstrates that ably with a rather nifty energy-harvesting build.

The card is based around a thin PCB in the typical business card size. It’s populated by 21 Charlieplexed LEDs, a small microcontroller, and some supporting components. Now, this is normally where you might expect the device to be powered by a small coin cell, maybe deftly integrated into the PCB thickness itself to make the card less cumbersome. But no—[Wilson] went a different route. The thing is that in 2026, most of us are carrying phones with NFC readers built in. Thus, the card was built to harvest this source of energy with a PCB trace antenna, designed with the aid of STM’s antenna inductance tools and an LLM script lobbed into KiCad. All one needs to do is to pop the card on the back of a phone and the LEDs animate joyfully.

Design files are on Github for the curious. You might also like to check out some of the fancy business cards we’ve featured in the past. Of course, if you’re working on just such a project yourself, you’re more than welcome to send it in to the tipsline!

Simulating UAVs In Unreal Engine

August 31, 2026 by 2 Comments

When it comes to building real-world flying vehicles, testing can be arduous and expensive. You have to find somewhere to fly, then you have to contend with environmental conditions and the possibility of damaging your craft if things go wrong. Simulation is a great solution to this, allowing testing without so much risk. To that end, [AlexanderRex] whipped up a platform for testing UAVs from the comfort of your computer desk.

PteroSim is intended as a comprehensive test bench for simulating autonomous aerial vehicles. It can run PX4, ArduPilot, and Betaflight binaries right in the simulator. The autopilot code is given simulated sensor data, and in turn responds with actuator commands, just as it would in a real craft. The simulator runs the flight dynamics using JSBSim, and the resulting scene is rendered in Unreal Engine 5.

If you’ve ever wanted to quickly road test different autopilot settings without heading out to the field or risking hardware, this is a great way to do so. It’s hard to beat the speed of iteration that is possible when testing on the computer on your desk. We’ve featured similar work before, too.

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