Oil-Immersed Raspberry Pi Keeps Its Cool Under Heavy Loads

As a general rule, liquids and electronics don’t mix. One liquid bucks that trend, though, and can contribute greatly to the longevity of certain circuits: oil. Dielectric oil cools and insulates everything from the big mains transformers on the pole to switchgear in the substation. But what about oil for smaller circuits?

[Lord_of_Bone] was curious to see if an oil-cooled Raspberry Pi is possible, and the short answer is: for the most part, yes. The experimental setup seen in the video below is somewhat crude — just a Pi running Quake 3 for an hour to really run up the CPU temperature, which is monitored remotely. With or without heatsinks mounted, in free air the Pi ranges from about 50°C at idle to almost 70°C under load, which is pretty darn hot. Dunking the Pi in a bath of plain vegetable oil, which he admits was a poor choice, changes those numbers dramatically: 37°C at idle and an only warmish 48°C after an hour of gaming. He also tested the Pi post-cleaning, which is where he hit a minor hiccup. The clean machine started fine but suffered from a series of reboots shortly thereafter. Twelve hours later the Pi was fine, though, so he figures a few stray drops of water that hadn’t yet evaporated were to blame.

Is oil immersion a practical way to cool a Pi? Probably not. It doesn’t mean people haven’t tried it before, of course, but we applaud the effort and the careful experimentation.

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NanoPi Cluster Is Quiet, Cool And Has Blinky Lights

We’ve seen the supercomputer cluster work of [Nick Smith] from the UK before, but his latest build is quite lovely. This time around, he put together a 96-core supercomputer using the NanoPi Fire3, a Raspberry Pi alternative that has double the number of cores. His post takes you through how he built the supercomputer cluster, from designing the laser-cut acrylic case to routing the power cables.

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Commodore 64 to Raspberry Pi Conversion is Respectful & Complete

We’re big fans of taking old computers and giving them a new lease on life, but only when it is done respectfully. That means no cutting, no hot glue, and no gouging out bits to make the new computer fit. It’s best if it can be done in a way that the original parts can be restored if required.

This Commodore 64 to Raspberry Pi conversion from [Mattsoft] definitely fits our criteria here, as it uses the old keyboard, joystick connectors and output portholes for the required authentic look. It does this through the clever use of a couple of 3D-printed parts that hold the Raspberry Pi and outputs in place, mounting them to use the original screw holes in the case.

Combine the Pi with a Keyrah V2 to connect the C64 keyboard and a PowerBlock to juice up all of the parts, and you’ve got a fully updated C64 that can use the keyboard, joysticks or other peripherals, but which also comes with a HDMI port, USB and other more modern goodies.

[Mattsoft] suggests using Combian 64, a C64 emulator for the Pi for the authentic look and feel. Personally, I might use it as a thin client to the big-ass PC with 16 CPU cores and 32GB of memory that’s hidden in my basement, but that’s just because I enjoy confusing people.

Making Custom Silicon For The Latest Raspberry Pi

The latest Raspberry Pi, the Pi 3 Model B+, is the most recent iteration of hardware from the Raspberry Pi Foundation. No, it doesn’t have eMMC, it doesn’t have support for cellular connectivity, it doesn’t have USB 3.0, it doesn’t have SATA, it doesn’t have PCIe, and it doesn’t have any of the other unrealistic expectations for a thirty-five dollar computer. That doesn’t mean there wasn’t a lot of engineering that went into this new version of the Pi; on the contrary — the latest Pi is filled with custom silicon, new technologies, and it even has a neat embossed RF shield.

On the Raspberry Pi blog, [James Adams] went over the work that went into what is probably the most significant part of the new Raspberry Pi. It has new, custom silicon in the power supply. This is a chip that was designed for the Raspberry Pi, and it’s a great lesson on what you can do when you know you’ll be making millions of a thing.

The first few generations of the Raspberry Pi, from the original Model B to the Zero, used on-chip power supplies. This is what you would expect when the RAM is soldered directly to the CPU. With the introduction of the Raspberry Pi 2, the RAM was decoupled from the CPU, and that meant providing more power for more cores, and the rails required for LPDDR2 memory. The Pi 2 required voltages of 5V, 3.3V, 1.8V, and 1.2V, and the sequencing to bring them all up in order. This is the job for a power management IC (PMIC), but surprisingly all the PMICs available were more expensive than the Pi 2’s discrete solution.

The MXL7704, with four switching power supplies. The four symmetric gray and brown bits are inductors.

However, where there are semiconductor companies, there’s a possibility of having a custom chip made. [James] talked to [Peter Coyle] of Exar in 2015 (Exar was then bought by MaxLinear last year) about building a custom chip to supply all the voltages found in the Raspberry Pi. The result was the MXL7704, delivered just in time for the production of the Raspberry Pi 3B+.

The new chip takes the 5V in from the USB port and converts that to two 3.3V rails, 1.8V and 1.2V for the LPDDR2 memory, 1.2V nominal for the CPU, which can be raised and lowered via I2C. This is an impressive bit of engineering, and as any hardware designer knows, getting the power right is the first step to a successful product.

With the new MXL7704 chip found in the Raspberry Pi 3B+, the Pi ecosystem now has a simple and cheap chip for all their future revisions. It might not be SATA or PCIe or eMMC or a kitchen sink, but this is the kind of engineering that gives you a successful product rather than a single board computer that will be quickly forgotten.

Friday Hack Chat: Everything Raspberry Pi

The Raspberry Pi is six years old now, and in that time it’s become the most popular single board computer. Over these last few years, the Pi has improved from a relatively anemic board based on a smartphone SoC to a surprisingly fast board that’s loaded up with some of the best software and the best community support we’ve ever seen. There’s an awful lot you can do with a Pi, and the continued support of the Raspberry Pi Foundation has enabled millions of people to get their hands on a cheap computer that runs Linux. It’s great.

Now it’s your turn to ask the engineers behind this tiny little computer what’s going on in the world of Pi. We’re having a Hack Chat this Friday, and you’re invited.

Our guest for this week’s Hack Chat will be [Roger Thornton], principal hardware engineer for the Raspberry Pi, where he oversees design, test, compliance, and production for Raspberry Pi products. Previously, [Roger]’s work for Broadcom included being part of the team that characterized and tested numerous SoCs including the BCM2835/6/7 found in various Pis. He also has experience in the smart home and IoT fields from working in a consultancy where be helped bring chips to market.

[Roger]’s most recent work was announced today; the Raspberry Pi 3 Model B+ is the latest in a long line of Pis, and while it’s not the octocore ARM monster with SATA and PCIe and Gigabit networking and 4G that the power-hungry have been clamoring for, it is more capable than its predecessor and still only costs less than forty bucks.

This is also the second time [Roger] has been a guest on our Hack Chats. You can check out the transcript of the 2017 chat here.

During this chat, we’re going to be discussing the future of Raspberry Pi products, Pi events around the world, and a question on the minds of many: where you can buy Pi Zeros in quantity. You are, of course, encouraged to add your own questions to the Hack Chat. You can do that by leaving the questions as a comment on this Hack Chat’s event page.

join-hack-chat

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This week it’s going down at the usual time, on noon, Pacific, Friday, March 16th  Want to know what time this is happening in your neck of the woods? Have a countdown timer!

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

Archimedes Would Have Known Better If He Could Count To A Million

Today is March 14th, or Pi Day because 3.14 is March 14th rendered in month.day date format. A very slightly better way to celebrate the ratio of a circle’s circumference to its diameter is July 22nd, or 22/7 written in day/month order, a fractional approximation of pi that’s been used for thousands of years and is a better fit than 3.14. Celebrating Pi Day on July 22nd also has the advantage of eschewing middle-endian date formatting.

But Pi Day is completely wrong. We should be celebrating Tau Day, to celebrate the ratio of the circumference to the radius instead of the diameter. That’s June 28th, or 6.283185…. Nonetheless, today is Pi Day and in the absence of something truly new and insightful — we’re still waiting for someone to implement a spigot algorithm in 6502 assembly, by the way — this is a fantastic opportunity to discuss something tangentially related to pi, the history of mathematics, and the idea that human knowledge builds upon itself in an immense genealogy stretching back to the beginning of history.

This is our Pi Day article, but instead of complaining about date formats, or Tau, we’re going to do something different. This is how you approximate pi with the Monte Carlo method, and how anyone who can count to a million can get a better approximation of one the fundamental constants of the Universe than Archimedes.

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Raspberry Pi Gets Faster CPU and Better Networking in the New Model 3 B+

While the Raspberry Pi’s birthday (and the traditional release date for the newest and best Pi) was a few weeks ago, Pi Day is a fitting enough date for the introduction of the best Pi to date. The Raspberry Pi 3 Model B+ is the latest from the Raspberry Pi foundation. It’s faster, it has better networking, and most interestingly, the Pi 3 Model B+ comes with modular compliance certification, allowing anyone to put the Pi into a product with vastly reduced compliance testing.

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