An ATTiny GPU Fan Controller That Sticks

August 2, 2025 by Heidi Ulrich 14 Comments

When your GPU fan goes rogue with an unholy screech, you either shell out for a new one or you go full hacker mode. Well, [ashafq] did the latter. The result is a delightfully nerdy fan controller powered by an ATTiny85 and governed by a DS18B20 temperature sensor. We all know a silent workstation is golden, and there’s no fun in throwing money at an off-the-shelf solution. [ashafq]’s custom build transforms a whiny Radeon RX 550 into a cool, quiet operator. Best of all: it’s built from bits likely already in your junk drawer.

To challenge himself a bit, [ashafq] rolled his own temperature-triggered PWM logic using 1-wire protocol on an ATtiny85, all without libraries or bloated firmware. The fan’s speed only ramps up when the GPU gets toasty, just like it should. It’s efficient and clever, and that makes it a fine hack. The entire system runs off a scavenged 12V fan. He could have used a 3D printer, but decided to stick onto the card with double-sided tape. McGyver would approve.

The results don’t lie: idle temps at 40 °C, load peaking at 60 °C. Quieter than stock, smarter than stock, and way cheaper too. The double-sided tape may not last, but that leaves room for improvement. In case you want to start on it yourself, read the full write-up and feel inspired to build your own. Hackaday.io is ready for the documentation of your take on it.

Modifying fans is a tradition around here. Does it always take a processor? Nope.

This image created using GPT-4o on Poe using the prompt “picture of an upright freezer connected to a computer for temperature monitoring, together with a graph and an alarm siren. Suitable for a professional blog. Be humorous and use a vintage theme.”

Freezer Monitoring: Because Ice Cream Is A Dish Best Served Cold

July 21, 2025 by John Elliot V 23 Comments

[Scott Baker] wrote in to let us know about his freezer monitor.

After a regrettable incident where the ice cream melted because the freezer failed [Scott] decided that what was called for was a monitoring and alerting system. We enjoyed reading about this hack, and we’ll give you the details in just a tick, but before we do, we wanted to mention [Scott]’s justifications for why he decided to roll his own solution for this, rather than just using the bundled proprietary service from the white goods manufacturer.

We’re always looking for good excuses for rolling our own systems, and [Scott]’s list is comprehensive: no closed-source, no-api cloud service required, can log with high fidelity, unlimited data retention, correlation with other data possible, control over alerting criteria, choice of alerting channels. Sounds fair enough to us!

Continue reading “Freezer Monitoring: Because Ice Cream Is A Dish Best Served Cold” →

Keep Track Of The Compost With LoRaWAN

June 23, 2025 by Tyler August 7 Comments

Composting doesn’t seem difficult: pile up organic matter, let it rot. In practice, however, it’s a bit more complicated– if you want that sweet, sweet soil amendment in a reasonable amount of time, and to make sure any food-born pathogens and weed seeds don’t come through, you need a “hot” compost pile. How to tell if the pile is hot? Well, you could go out there and stick your arm in like a schmuck, or you could use [Dirk-WIllem van Gulik]’s “LORAWAN Compostheap solarpowered temperaturesensor” (sic).

The project is exactly what it sounds like, once you add some spaces: a solar-powered temperature sensor that uses LoRaWAN to track temperatures inside (and outside, for comparison) the compost heap year round. Electronically it is pretty simple: a Helltech CubeCell AB01 LoraWAN module is wired up with three DS18B20 temperature sensors, a LiPo battery and a solar panel. (The AB01 has the required circuitry to charge the battery via solar power.) Continue reading “Keep Track Of The Compost With LoRaWAN” →

Beverage Coaster Indicates Ideal Drinking Temperature

March 8, 2024 by Kristina Panos 9 Comments

When temperatures plummet, there’s nothing like a hot beverage to keep you warmed up inside. [Palingenesis] aka [Tim] sure does fancy a nice cuppa, but only within a certain temperature range is it ideal to drink. In an attempt to signal when the time is just right, he created various iterations of a hot beverage coaster.

To be clear, this is a plywood sandwich that does not keep the beverage warm, though that would be an interesting addition to the project. Rather, it indicates when the beverage’s temperature is just right using LEDs. When it’s too hot, the red LEDs are lit. The green LEDs flash while it’s just right, and once [Tim]’s tea has gone cold, the blue LEDs take center stage.

The brains of the operation is an STM8S103F module, aka the Blue Pill, which is paired with a DS18B20 temperature sensor. [Tim]’s original coaster has one in a TO-92 package embedded in the top layer, but ultimately he went with the probe version as it reads a truer temperature by virtue of being directly in the liquid. Be sure to check out the video after the break which covers planning the original version.

If you do want to keep you drink warm, here’s an ESP8266-based solution. If you’re more into looks, check out this blinkencoaster.

Continue reading “Beverage Coaster Indicates Ideal Drinking Temperature” →

Keep Cool With This Open Source AVR Fan Controller

March 12, 2021 by Tom Nardi 12 Comments

We’ve all got projects kicking around that we haven’t had time to document for our own purposes, let alone expose to the blinding light of the Internet. There are only so many hours in a day, and let’s face it, building the thing is a lot more fun than taking pictures of it. It took [Matthew Millman] the better part of a decade to combine everything he’s learned over the years to finally document the definitive version of his open source intelligent fan controller, but looking at the final result, we’re glad he did.

At the heart of this board is an ATmega328P, but don’t call it an Arduino. [Matthew] makes it very clear that if you want to hack around with the code for this project, you’re going to need to not only have a programmer for said chip, but know your way around AVR-GCC. He’s provided pre-built binaries for those content to run with the default settings, but you’ve still got to get it flashed onto the chip yourself. The project is designed to use the common DS18B20 temperature sensor, and as an added bonus, the firmware can even check if yours is a bootleg (spoilers: there’s an excellent chance it is).

Arguably the most interesting feature of this fan controller is its command line interface. Just plug into the serial port on the board, open your terminal emulator, and you’ll have access to a concise set of functions for querying the sensors as well as setting temperature thresholds and RPM ranges for the fans. There’s even a built-in “help” function should you forget a command or the appropriate syntax.

Originally [Matthew] developed this project as a way to control multiple fans inside of a PC case, but naturally, things have changed quite a bit since those early days. While today there’s no shortage of fancy controllers that can handle throttling an array of fans based on the internal temperature of your rig, there’s still something to be said for rolling your own solution. More importantly, there’s certainly other potential uses for a fully open source programmable fan controller.

Oceanography As Open As The Seas

January 17, 2020 by Kristina Panos 12 Comments

With Earth in the throes of climate change and no suitable Planet B lined up just yet, oceanography is as important now as it has ever been. And yet, the instruments relied upon for decades to test ocean conditions are holding steady within the range of expensive to prohibitively expensive. Like any other area of science, lowering the barrier of entry has almost no disadvantages — more players means more data, and that means more insight into the inner workings of the briny deep.

[Oceanography for Everyone] aims to change all that by showing the world just how easy it is to build an oceanographic testing suite that measures conductivity (aka salinity), temperature, and depth using common components. OpenCTD is designed primarily for use on the continental shelf, and has been successfully tested to a depth of 100 meters.

An Adalogger M0 and RTC Featherwing run the show from their waterproof booth in the center of the PVC tube. There’s a 14-bar pressure sensor for depth, a trio of DS18B20s for temperature averaging, and a commercial conductivity probe that gathers salinity data. These sensors are fed through a 3D-printed base plate and ultimately potted in stainless steel epoxy. The other end of the tube is sealed with a mechanical plug that seats and unseats with the whirl of a wingnut.

We particularly like the scratch-built magnetic slide switch that turns OpenCTD on and off without the need to open the cylinder. If you’d like to build one of these for yourself, take a deep dive into [Oceanography for Everyone]’s comprehensive guide — it covers the components, construction, and calibration in remarkable detail. The switch is explained starting on page 50. You can find out more about the work Oceanography for Everyone is doing at their site.

As far as cheap waterproof enclosures go, PVC is a great choice. It works well for underwater photography, too.

Hackaday Links: November 17, 2019

November 17, 2019 by Dan Maloney 8 Comments

Friday, November 15, 2019 – PASADENA. The 2019 Hackaday Superconference is getting into high gear as I write this. Sitting in the Supplyframe HQ outside the registration desk is endlessly entertaining, as attendees pour in and get their swag bags and badges. It’s like watching a parade of luminaries from the hardware hacking world, and everyone looks like they came ready to work. The workshops are starting, the SMD soldering challenge is underway, and every nook and cranny seems to have someone hunched over the amazing Hackaday Superconference badge, trying to turn it into something even more amazing. The talks start on Saturday, and if you’re not one of the lucky hundreds here this weekend, make sure you tune into the livestream so you don’t miss any of the action.

The day when the average person is able to shoot something out of the sky with a laser is apparently here. Pablo, who lives in Argentina, has beeing keeping tabs on the mass protests going on in neighboring Chile. Huge crowds have been gathering regularly over the last few weeks to protest inequality. The crowd gathered in the capital city of Santiago on Wednesday night took issue with the sudden appearance of a police UAV overhead. In an impressive feat of cooperation, they trained 40 to 50 green laser pointers on the offending drone. The videos showing the green beams lancing through the air are quite amazing, and even more amazing is the fact that the drone was apparently downed by the lasers. Whether it was blinding the operator through the FPV camera or if the accumulated heat of dozens of lasers caused some kind of damage to the drone is hard to say, and we’d guess that the drone was not treated too kindly by the protestors when it landed in the midsts, so there’s likely not much left of the craft to do a forensic analysis, which is a pity. We will note that the protestors also trained their lasers on a police helicopter, an act that’s extremely dangerous to the human pilots which we can’t condone.

In news that should shock literally nobody, Chris Petrich reports that there’s a pretty good chance the DS18B20 temperature sensor chips you have in your parts bin are counterfeits. Almost all of the 500 sensors he purchased from two dozen vendors on eBay tested as fakes. His Github readme has an extensive list that lumps the counterfeits into four categories of fake-ness, with issues ranging from inaccurate temperature offsets to sensors without EEPROM that don’t work with parasitic power. What’s worse, a lot of the fakes test almost-sorta like authentic chips, meaning that they may work in your design, but that you’re clearly not getting what you paid for. The short story to telling real chips from the fakes is that Maxim chips have laser-etched markings, while the imposters sport printed numbers. If you need the real deal, Chris suggests sticking with reputable suppliers with validated supply chains. Caveat emptor.

A few weeks back we posted a link to the NXP Homebrew RF Design Challenge, which tasked participants to build something cool with NXP’s new LDMOS RF power transistors. The three winners of the challenge were just announced, and we’re proud to see that Razvan’s wonderfully engineered broadband RF power amp, which we recently featured, won second place. First place went to Jim Veatch for another broadband amp that can be built for $80 using an off-the-shelf CPU heatsink for thermal management. Third prize was awarded to a team lead by Weston Braun, which came up with a switch-mode RF amp for the plasma cavity for micro-thrusters for CubeSats, adorably named the Pocket Rocket. We’ve featured similar thrusters recently, and we’ll be doing a Hack Chat on the topic in December. Congratulations to the winners for their excellent designs.