Lowering The Electricity Bill By Mining Cryptocurrency

March 1, 2021 by Danie Conradie 119 Comments

Wherever you are in the world, the chances are that a large portion of your utility bill is for heating. This was certainly the case for [Christian Haschek], who realized he can use a cryptocurrency mining rig to offset some of his heating costs.

[Christian]’s central ventilation and water heating is handled by a heat pump, which uses a lot of electricity, especially in the Austrian winter. When it draws in cool air, it first needs to heat it to the thermostat temperature before venting it to the house. Cryptocurrency mining rigs are also heavy electricity users, but they also produce a lot of heat, which can be used to preheat the air going to the heat pump. [Christian] had four older AMD R9 390 GPUs (equivalent to the Nvidia GeForce GTX 970) lying around, so he mounted them in a server case and piped the heat pump’s air intake through the case.

At the time he did the tests, earnings from mining were enough to cover half of his heating bill, even after paying for the mining rig’s electricity. That is not taking into account the electricity savings from the preheated air. He only shows the results of one evening, where it dropped his electricity usage from around 500Wh to below 250Wh. We would like to see the long-term results, and it would be an interesting challenge to build a model to calculate the true costs or savings, taking into account all the factors. For instance, it could be possible to save costs even if the mining rig itself is running at a slight loss.

Of course, this is not a new idea. A quick internet search yields several similar projects and even some commercial crypto mining space heaters. We do like the fact that [Christian] reused some hardware he already had and integrated it into his central heating rather than using it as a mobile unit.

When [Christian] isn’t building crypto heaters, he can be found flooding phishing scams with fake data, or tracking down corporate spies.

The Raspberry Pi Pico Can’t Run Linux. But It Can Run Fuzix.

February 19, 2021 by Jenny List 96 Comments

The great divide in terms of single board computers lies between those that can run some form of Linux-based distribution, and those that can not. For example the Raspberry Pi Zero is a Linux board, while the Raspberry Pi Pico’s RP2040 processor lacks the required hardware to run everybody’s favourite UNIX-like operating system. That’s not to say the new board from Cambridge can’t run any UNIX-like operating system though, as [David Given] shows us with his Fuzix port.

Fuzix is a UNIX-like operating system for less capable processors, more in the spirit of those original UNIXes than of a modern Linux-based distribution. It’s the work of the respected former Linux kernel developer and maintainer [Alan Cox], and consists of a kernel, a C compiler, and a set of core UNIX-like applications.

The RP2040 port maybe needs a little more work to be considered stable. For now, the multitasking support isn’t quite there and NAND flash support is broken, but it does have SD card support for a proper UNIX filesystem and the full set of core tools. Perhaps most interestingly, it only occupies a single core of the dual-core chip, leaving the possibility of the other core and those PIOs to be used for other purposes.

Fuzix has made the occasional appearance here over the years, but perhaps not as often as it should. If you’d like to learn a little more about the genesis of UNIX, we took a look in 2019.

Header: Michiel Henzler (CC BY-SA 4.0).

This Stackable Pi Portable Is Ready To Rumble

February 17, 2021 by Tom Nardi 5 Comments

The proliferation of desktop 3D printing and powerful single-board computers like the Raspberry Pi has given rise to an absolute explosion of small bespoke computing devices. Whether or not you think these cobbled together devices are close enough to Gibson’s original vision to call them cyberdecks, it’s a remarkable shift from the norm that brings us closer to the “High Tech, Low Life” philosophy so prevalent in cyberpunk literature and films.

[Jay Doscher] has been on the front lines of this movement for some time now, producing several very popular designs. His latest creation leans hard into the more utilitarian aspects of the cyberpunk ethos, inspired more by the grit of The Expanse than the lusciously upholstered interiors of Star Trek’s Enterprise-D. The culmination of lessons learned over the last several years, the new Kuiper Deck is cheaper and easier to build than his previous designs, thanks at least in part to the fact that you no longer need to go out and get an expensive Pelican case.

Like his previous designs, the Kuiper Deck makes extensive use of 3D printed components. But this time around, [Jay] is using an array of smaller pieces that are bolted together on an acrylic front panel. This not only means the project is compatible with a wider array of machines, such as the Prusa Mini, but it’s also easier to print as larger parts have an annoying tendency to warp. The downside is that you’ll need some way to get the acrylic panel cut to shape, though you can buy one through him if you don’t have any way to get it made locally.

In place of the Pelican case his previous designs used as an enclosure, [Jay] has found a heavy-duty stackable plastic tote available from McMaster Carr for $12 USD. It’s not particularly nice looking, nor is it waterproof. But that’s also sort of the point. If you’re just trying to put together a small computer that you can toss around the shop and not have to worry about breaking, the Pelican case was always a bit overkill.

The electronics bill of materials is similarly sparse, comprising mainly of the Raspberry Pi 4, a cooling fan, and a 10 inch LCD from Pimoroni. Everything gets screwed to the rear of the panel and connected with pre-made cables, making assembly very simple. That said, there’s still plenty of room inside the case for custom hardware should you want to put something custom together such as a mobile software defined radio rig.

[Jay] created the original Raspberry Pi Field Unit in 2015, but it wasn’t until he unveiled the revised Raspberry Pi Recovery Kit in 2019 that the idea of sticking a Raspberry Pi into a Pelican case became something of hacker meme. It sounds like the Kuiper Deck is going to be his final word on the subject for now, but it’s a safe bet we’ll be seeing folks putting together similar builds for years to come.

A Volume Control From A VCR Drum

February 15, 2021 by Jenny List 21 Comments

The VHS VCR has now passed from widespread use, and can thus be found as a ready supply of interesting parts for the curious hardware hacker. [Clewsy] has a novel use for a VCR head scanning drum, the part that is supposed to be tasked with reading information off of magnetic tape. Instead, it’s reading information from fingers as the knob for a USB volume control. Underneath the drum is an optical encoder disk which is read by an ATmega32U4 for USB interfacing with a host computer.

The helical-scan video recorder was a mechanically complex solution to the problem of recording a high-bandwidth video signal onto a tape that could be made slow-moving enough to be practical. By recording the video in diagonal stripes across the tape from a fast-moving spinning head they avoided the need for huge reels of tape, enabling hours of video to be fitted into a roughly book-size cassette.

While over time the mechanics of a VCR mechanism were simplified and cheapened to a great extent, the heads and drum were the one area that could not be compromised. Thus the VCR head was for a time the most high-precision mechanical device owned by most consumers, and the drums usually have exceptionally nice bearings. All of this makes one a particularly good choice for a volume knob or indeed any other large rotational control, so much so that we’re surprised it hasn’t become a more frequent occurrence. So scour the electronic junk, and you might just find the ultimate in free high quality control hardware.

Of course, this isn’t the only thing a VCR head drum can do. How about a centrifuge?

PC Overclocking With An Air Conditioner

February 11, 2021 by Al Williams 51 Comments

We never insist that a hack be practical. [Tech Ingredients] is living proof as they modded a computer case to use a window air conditioner for overclocking a computer. They think they haven’t hit the ceiling yet, and got their AMD Ryzen 8-core processor up to 4.58 GHz.

An advantage of forcing air from an air conditioner is that the air forced into the system is quite dry and clean. The trick is to create a simple duct to attach to a 5,000 BTU air conditioner. It doesn’t actually interface with the CPU cooling block, instead it just forces cool air into the case and this tends to cool everything inside. Admittedly, it isn’t any worse than plunging your computer in liquid nitrogen, and we’ll admit that air conditioning units are made to keep large areas cold and work at high duty cycles. With the air conditioning running, they disconnected at least some of the stock fans. The temperatures stayed cool even at high speeds.

Continue reading “PC Overclocking With An Air Conditioner” →

The Modding, Restoration, And Demise Of A $3M Analog Computer

February 9, 2021 by Chris Lott 24 Comments

How do you rapidly record the output from your three million dollar analog computer in the 1940s when the results are only available on analog meters? The team responsible for the Westinghouse 1947 AC Network Calculator at Georgia Tech was faced with just this problem and came up with a nifty solution — hack the control panel and wire in a special-purpose drafting table.

What Is It?

What is this beast of a computer? Machines of this type were developed during and after World War 2, and strictly speaking, belong in the category of scale models rather than true computers. Although these machines were very flexible, they were primarily designed to simulate power distribution grids. There is a lot of theory under the hood, but basically a real world, multi-phase distribution system would be scaled to single-phase at 400 Hz for modeling.

The engineers would “program” the machine by connecting together the appropriate circuit elements (like capacitors, inductors, transmission lines, generators, etc.) on big patch panels. Thus programmed, a 10 kW motor-generator located in the basement would be started up and the simulation was underway. Continue reading “The Modding, Restoration, And Demise Of A $3M Analog Computer” →

Building A Cheap Kubernetes Cluster From Old Laptops

February 8, 2021 by Lewin Day 28 Comments

Cluster computing is a popular choice for heavy duty computing applications. At the base level, there are hobby clusters often built with Raspberry Pis, while the industrial level involves data centers crammed with servers running at full tilt. [greg] wanted something cheap, but with x86 support – so set about building a rig his own way.

The ingenious part of [greg]’s build comes in the source computers. He identified that replacement laptop motherboards were a great source of computing power on the cheap, with a board packing an i7 CPU with 16GB of RAM available from eBay for around £100, and with i5 models being even cheaper. With four laptop motherboards on hand, he set about stacking them in a case, powering them, and hooking them up with the bare minimum required to get them working. With everything wrapped up in an old server case with some 3D printed parts to hold it all together, he was able to get a 4-node Kubernetes cluster up and running for an absolute bargain price.

We haven’t seen spare laptop motherboards used in such a way before, but we could definitely see this becoming more of a thing going forward. The possibilities of a crate full of deprecated motherboards are enticing for those building clusters on the cheap. Of course, more nodes is more better, so check out this 120 Pi cluster to satiate your thirst for raw FLOPs.