A PC That Uses Hot Coffee As Coolant

August 7, 2025 by Lewin Day 38 Comments

Modern computers generate a great deal of heat when under load, thus we cool them with fans and sometimes even water cooling systems. [Doug MacDowell] figured that water was alright, but why not use coffee instead?

*Someone tell us how [Doug] made this graph look like it’s right out of a 1970s college textbook.*

The concept is simple enough — replace water in a PC’s cooling loop with fresh-brewed coffee. [Doug] fully integrated an entire PC build on to the side of a General Electric drip coffee maker. It’s an absolute mess of tubes and wires, but it’s both a PC and a functional coffee maker in one.

The coffee maker percolates coffee as per normal into the carafe, and from there, it’s then pumped through two radiators on top of the PC. From there, it circulates to the water block on top of the CPU, and then back to the carafe on the coffee maker where the cycle repeats. Doug notes the coffee is initially so hot (90 C) that the PC is at risk of crashing, but after 75 minutes circulating through the system, the coffee and CPU sit at an equilibrium temperature of 33 C.

You can’t really drink coffee from this machine. PC water cooling components are not food safe in any way, and [Doug] notes mold will become an issue over time. For short periods at least, though, it’s possible to sort-of-cool your computer with hot, fresh coffee if you really want to do that.

We’ve featured some great hacks of conventional coffee machines over the years, including this fantastic talk at Supercon 2023.

Continue reading “A PC That Uses Hot Coffee As Coolant” →

2025 One Hertz Challenge: An Animated Ferrofluid Display

August 6, 2025 by Lewin Day 12 Comments

Ferrofluid is fun. You’ve probably seen all kinds of demos with it bouncing around in response to magnetic fields, or dancing near a speaker. [beastie417] decided to turn the entertaining fluid into a display.

The basic concept of the ferrofluid display. Note the header image of this article shows the electromagnet array without the ferrofluid pane in place.

The concept is straightforward enough. First, construct a tank of ferrofluid with a white panel behind it for contrast. Then, place it in front of a grid of electromagnets. Now you have many “pixels” you can turn on and off. You turn a magnet on to attract ferrofluid to that point, and turn it off to let it fall away. Since the ferrofluid contrasts with the white background, you have a viable display!

[beastie417] notes that while the concept is simple, the execution is hard. Ferrofluid can be very difficult to work with, instantly staining many materials like acrylic and even glass that isn’t properly prepared. It can also be quite expensive to construct a display like this, with [beastie417] noting their 16×12 pixel design costing approximately $700 thus far. Then you have to figure out how to drive all the pixels—this project uses DRV8908 coil driver ICs running off a microcontroller which controls the display and handles animations.

We’ve seen some great ferrofluid displays before, like this neat build that could even create readable glyphs. Meanwhile, if you’re doing rad things with the coolest fluid of the new millennium, don’t hesitate to let us know!

A Robot Controller With The Compute Module 5

August 6, 2025 by Lewin Day 16 Comments

The regular Raspberry Pi line is a flexible single-board computer, but sometimes you might find yourself wishing for a form factor that was better designed for installation into a greater whole. This is why the Compute Module variants exist. Indeed, leveraging that intention, [Hans Jørgen Grimstad] has used the powerful Compute Module 5 as the heart of his “Overlord” robot controller.

The Compute Module 5 offers a powerful quad-core 64-bit ARM chip running at 2.4 GHz, along with anywhere from 2 to 16GB of RAM. You can also get it with WiFi and Bluetooth built in onboard, and it comes with a wide range of I2C, SPI, UART, and GPIO pins to serve whatever ends you envision for them. It’s a whole lot of capability, but the magic is in what you do with it.

For [Hans], he saw this as a powerful basis for a robot controller. To that end, he built a PCB to accept the Compute Module 5, and outfit it with peripherals suited to robotics use. His carrier board equips it with an MCP2515 CAN controller and a TJA1051 CAN transceiver, ideal for communicating in a timely manner with sensors or motor controllers. It also has a 9-axis BNO055 IMU on board, capable of sensor fusion and 100Hz updates for fine sensing and control. The board is intended to be easy to use with hardware like Xiaomi Cybergear motors and Dynamixels servos. As a bonus, there is power circuitry on board to enable it to run off anything from 5 to 36V. While GPIOs aren’t exposed, [Hans] notes that you can even pair it with a second Pi if you want to use GPIOs or camera ports or do any other processing offboard.

If you’re looking for a place to start for serious robot development, the Overlord board has plenty of capability. We’ve explored the value of the Compute Module 5 before, too. Meanwhile, if you’re cooking up your own carrier boards, don’t hesitate to let the tipsline know!

Australia’s Space Program Finally Gets Off The Pad, But Only Barely

August 6, 2025 by Lewin Day 42 Comments

Australia is known for great beaches, top-tier coffee, and a laidback approach to life that really doesn’t square with all the rules and regulations that exist Down Under. What it isn’t known for is being a spacefaring nation.

As it stands, a startup called Gilmour Space has been making great efforts to give Australia the orbital launch capability it’s never had. After numerous hurdles and delays, the company finally got their rocket off the launch pad. Unfortunately, it just didn’t get much farther than that.

Continue reading “Australia’s Space Program Finally Gets Off The Pad, But Only Barely” →

A Speed Loader For Your 3D Printer Filament

August 6, 2025 by Lewin Day 23 Comments

Reloading filament on a 3D printer is hardly anyone’s favorite task, but it’s even worse when you’re trying to shove stiff filament down a long and winding Bowden tube. Enter the speed loader from [Mr Flippant], which aims to take the pain out of this mechanically-frustrating chore.

The design is simple enough. It’s a small handheld tool that uses a 12 VDC gear motor to drive a set of Bondtech-style drive gears that you might find in an extruder. They’re assembled in a 3D printed housing with a microswitch to activate the motor, and a 9 volt battery to supply the juice.

To use the device, first thread the filament into the beginning of the Bowden tube. The idler gear is on a hinge, such that clamping it into position around the filament with the main gear activates the microswitch and turns the motor on, driving the filament all the way to the extruder. Job done! [Mr Flippant] notes that the filament should be as straight and unkinked as possible for best results, but that’s good advice when 3D printing in general.

Funnily enough, around these parts, when we talk about speed loaders, we’re usually discussing tapes.

Continue reading “A Speed Loader For Your 3D Printer Filament” →

What Happens When Lightning Strikes A Plane?

August 5, 2025 by Lewin Day 24 Comments

Lightning is a powerful force, one seemingly capable of great destruction in the right circumstances. It announces itself with a searing flash, followed by a deep rumble heard for miles around.

Intuitively, it might seem like a lightning strike would be disastrous for something like a plane flying at altitude. And yet, while damage is possible, more often than not—a plane will get through a lightning storm unscathed. Let’s explore the physics at play.

Continue reading “What Happens When Lightning Strikes A Plane?” →

Spatial Audio In A Hat

August 5, 2025 by Lewin Day 5 Comments

Students from the ECE4760 program at Cornell have been working on a spatial audio system built into a hat. The project from [Anishka Raina], [Arnav Shah], and [Yoon Kang], enables the wearer to get a sense of the direction and proximity of objects in the immediate vicinity with the aid of audio feedback.

The heart of the build is a Raspberry Pi Pico. It’s paired with a TF-Luna LiDAR sensor which is used to identify the range to objects around the wearer. The sensor is mounted on a hat, so the wearer can pan the sensor from side to side to scan the immediate area for obstacles. Head tracking wasn’t implemented in the project, so instead, the wearer uses a potentiometer to indicate to the microcontroller the direction they are facing as they scan. The Pi Pico then takes the LIDAR scan data, determines the range and location of any objects nearby, and creates a stereo audio signal which indicates to the wearer how close those objects are and their relative direction using a spatial audio technique called interaural time difference (ITD).

It’s a neat build that provides some physical sensory augmentation via the human auditory system. We’ve featured similar projects before, too.

Continue reading “Spatial Audio In A Hat” →