Extreme Pi Overclocking With Mineral Oil

Liquid cooling is a popular way to get a bit of extra performance out of your computer. Usually this is done in desktops, where a special heat sink with copper tubing is glued to the CPU, and the copper tubes are plumbed to a radiator. If you want dive deeper into the world of liquid cooling, you can alternatively submerge your entire computer in a bath of mineral oil like [Timm] has done.

The computer in question here is a Raspberry Pi, and it’s being housed in a purpose-built laser cut acrylic case full of mineral oil. As a SoC, it’s easier to submerge the entire computer than it is to get a tiny liquid-cooled heat sink for the processor. While we’ve seen other builds like this before, [Timm] has taken a different approach to accessing the GPIO, USB, and other connectors through the oil bath. The ports are desoldered from the board and a purpose-built header is soldered on. From there, the wires can be routed out of the liquid and sealed off.

One other detail used here that  we haven’t seen in builds like this before was the practice of “rounding” the flat ribbon cable typically used for GPIO. Back in the days of IDE cables, it was common to cut the individual wires apart and re-bundle them into a cylindrical shape. Now that SATA is more popular this practice has been largely forgotten, but in this build [Timm] uses it to improve the mineral oil circulation and make the build easier to manage.

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Pedal Far With A Solar Powered Tricycle

More and more electric bikes have been rolling out into the streets lately as people realize how inexpensive and easy they are to ride and use when compared to cars. They can also be pedaled like a normal bike, so it’s still possible to get some exercise with them too. Most have a range somewhere around 10-30 miles depending on battery size, weight, and aerodynamics, but with a few upgrades such as solar panels it’s possible to go much, much further on a charge.

[The Rambling Shepherd] had a tricycle (in the US, generally still considered a bicycle from a legal standpoint) that he had already converted to electric with a hub motor and battery, and was getting incredible range when using it to supplement his manual pedaling. He wanted to do better, though, and decided to add a few solar panels to his build. His first attempt didn’t fare so well as the 3D-printed mounts for the panel failed, but with a quick revision his second attempt survived a 50-mile trip. Even more impressive, he only had his battery half charged at the beginning of the journey but was still able to make it thanks to the added energy from the panels.

If you’re thinking that this looks familiar, we recently featured a tandem tricycle that was making a solar-powered trip from Europe to China with a similar design. It has the advantage of allowing the rider to pedal in the shade, and in a relatively comfortable riding position compared to a normal bike. Future planned upgrades include an MPPT charge controller to improve the efficiency of the panels.

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A Guide For Driving LED Matrices

Building an LED matrix is a fun project, but it can be a bit of a pain. Usually it starts with hand-soldering individual LEDs and resistors together, then hooking them up to rows and columns so they can be driven by a microcontroller of some sort. That’s a lot of tedious work, but you can order an LED matrix pre-built to save some time and headache. You’ll still need a driver though, and while building one yourself can be rewarding there are many pitfalls and trade-offs to consider when undertaking that project as well. Or, you can consider one of a number of drivers that [deshipu] has outlined in detail.

The hangups surrounding the driver board generally revolve around the issue of getting constant brightness from LEDs regardless of how many in the row or column are illuminated at one time. Since they are typically driven one row or column at a time, the more that are on the lower the brightness each LED will have. Driver boards take different approaches to solving this problem, which usually involve a combination of high-speed scanning of the matrix or using a constant-current source in order to eliminate the need for resistors. [deshipu] outlines four popular chips that achieve these purposes, and he highlights their pros and cons to help anyone looking to build something like this.

Most of these boards will get you to an 8×8 LED matrix with no problem, with a few going a few pixels higher in either direction. That might be enough for most of our needs, but for something larger you’ll need other solutions like the one found in this 64×32 LED matrix clock. There are also even more complicated drivers if you go into extra dimensions.

Photo credit: Komatta [Public domain], from Wikimedia Commons

I’m Sorry, Alexander, I’m Afraid I Can’t Do That

Getting people to space is extremely difficult, and while getting robots to space is still pretty challenging, it’s much easier. For that reason, robots and probes have been helping us explore the solar system for decades. Now, though, a robot assistant is on board the ISS to work with the astronauts, and rather than something impersonal like a robot arm, this one has a face, can navigate throughout the ship, and can respond to voice inputs.

The robot is known as CIMON, the Crew Interactive Mobile Companion. Built by Airbus, this interactive helper will fly with German astronaut Alexander Gerst to test the concept of robotic helpers such as this one. It is able to freely move about the cabin and can learn about the space it is in without being specifically programmed for it. It processes voice inputs similarly to a smart phone, but still processes requests on Earth via the IBM Watson AI. This means that it’s not exactly untethered, and future implementations of this technology might need to be more self-contained for missions outside of low Earth orbit.

While the designers have listened to the warnings of 2001 and not given it complete control of the space station, they also learned that it’s helpful to create an interactive robot that isn’t something as off-putting as a single creepy red-eye. This robot can display an interactive face on the screen, as well as use the same screen to show schematics, procedure steps, or anything else the astronauts need. If creepy design is more your style though, you can still have HAL watching you in your house.

Thanks to [Marian] for the tip!

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Agilent LCR Meter Teardown

Since 1999, one of the more popular manufacturers of test equipment has been Agilent, the spun-off former instrument division of Hewlett-Packard. From simple multimeters to fully-equipped oscilloscopes, they have been covering every corner of this particular market. And, with the help of [Kerry Wong] and his teardown of an Agilent LCR meter, we can also see that they’ve been making consistent upgrades to their equipment as well.

The particular meter that [Kerry] took apart was an Agilent U1731B, a capable LCR (inductance, capacitance, resistance) meter. He had needed one for himself and noted that while they’re expensive when new, they can be found at a bargain used, but that means dealing with older versions of hardware. For example, his meter uses an 8-bit ADC while the more recent U1733 series uses a 24-bit ADC. The other quality of this meter that [Kerry] made special note of was how densely populated the circuit board is, presumably to save on the design of a VLSI circuit.

While we don’t claim to stump for Agilent in any way, it’s good to know that newer releases of their equipment actually have improved hardware and aren’t just rebadged or firmware-upgraded versions of old hardware with a bigger price tag attached. Also, there wasn’t really any goal that [Kerry] had in mind besides sheer curiosity and a willingness to dive deep into electronics details, as those familiar with his other projects know already.

Growing Your Own Insulation

The latest craze in revolutionary materials science is no longer some carbon nanotube, a new mysterious alloy, or biodegradeable plastic. It seems as though a lot of new developments are coming out of the biology world, specifically from mycologists who study fungi. While the jury’s still out on whether or not it’s possible to use fungi to build a decent Star Trek series, researchers have in fact been able to use certain kinds of it to build high-performing insulation.

The insulation is made of the part of the fungus called the mycelium, rather than its more familiar-looking fruiting body. The mycelium is a strand-like structure of fungus which grows through materials in order to digest them. This could be mulch, fruit, logs, straw, crude oil, or even live insects, and you might have noticed it because it’s often white and fuzzy-looking. The particular type of mycelium used here is extremely resistant to changes in temperature so is ideal for making insulation. As a bonus, it can be grown, not manufactured, and can use biological waste products as a growing medium. Further, it can grow to fit the space it’s given, and it is much less environmentally harmful than existing forms of insulation.

As far as performance is concerned, a reporter from the BBC tested it in an interesting video involving a frozen chocolate bar and a blowtorch, discovering also that the insulation is relatively flame-retardant. Besides insulation, though, there are many more atypical uses of fungi that have been discovered recently including pest control and ethanol creation. They can also be used to create self-healing concrete.

Thanks to [Michael] for the tip!

Photo of fungal mycelium: Tobi Kellner [CC BY-SA 3.0]

3D Printer Warning: Heating Plastic To High Temps is Not Healthy

If you’ve ever tried to cut a piece of acrylic with a tool designed to cut wood or metal, you know that the plastic doesn’t cut in the same way that either of the other materials would. It melts at the cutting location, often gumming up the tool but always releasing a terrible smell that will encourage anyone who has tried this to get the proper plastic cutting tools instead of taking shortcuts. Other tools that heat up plastic also have this problem, as Gizmodo reported recently, and it turns out that the plastic particles aren’t just smelly, they’re toxic.

The report released recently in Aerosol Science and Technology (first part and second part) focuses on 3D printers which heat plastic of some form or other in order to make it malleable and form to the specifications of the print. Similar to cutting plastic with the wrong tool, this releases vaporized plastic particles into the air which are incredibly small and can cause health issues when inhaled. They are too small to be seen, and can enter the bloodstream through the lungs. The study found 200 different compounds that were emitted by the printers, some of which are known to be harmful, including several carcinogens. The worst of the emissions seem to be released when the prints are first initiated, but they are continuously released throuhgout the print session as well.

Perhaps it’s not surprising that aerosolized plastic is harmful to breathe, but the sheer magnitude of particles detected in this study is worth taking note of. If you don’t already, it might be good to run your 3D printer in the garage or at least in a room that isn’t used as living space. If that’s not possible, you might want to look at other options to keep your work area safe.

Thanks to [Michael] for the tip!