Fill Your Hot Tub With Sand. For Science!

December 8, 2017 by 62 Comments

Here at Hackaday, we can understand if you don’t like sand. It’s coarse, rough and irritating, and it gets everywhere. With that said, [Mark Rober] discovered a great way to have fun with sand right in your own back garden.

We’ll preface this by stating that this isn’t the easiest hack to pull off on a lazy Saturday afternoon. You need a spare hot tub, plenty of pipe, and a seriously big air supply. But if you can pull it all together, the payoff is fantastic.

What [Mark] has achieved is turning a regular hot tub into a fluidized bed. In simple terms, this is where a solid particulate material (like sand) is made to act more like a fluid by passing pressurized fluid through the material. Through a carefully built series of drilled copper pipes, [Mark] manages to turn the hot tub into a fluidized bed, much to the enjoyment of his young nephews.

While it’s not the easiest hack to copy at home, [Mark] drives home the science of both the fluidized bed and why certain objects float or sink in the sand. It’s something that can also be easily tackled at a smaller scale, if you’re looking for something more achievable for the average maker.

For more sand science, how about using it to hold up your car?

[Thanks to Keith for the tip!]

Curbside Mower Gets Electric Transplant

December 8, 2017 by 28 Comments

There’s few things more exciting to a hacker or maker than seeing a piece of hardware on the curb. An old computer, an appliance, maybe if you’re really lucky some power tools. So we can only imagine the rush that known lawn equipment aficionado [AmpEater] had when he saw a seemingly intact push mower in the trash. The pull start was broken on the gas engine, but where this mower was going, it wouldn’t need a gas engine.

When he got the mower back to his garage, he started on the process of converting it over to electric. Of course this means basically everything but the wheels, handle, and deck would get tossed. But starting with a trashed gas mower still sounds a lot easier compared to trying to figure out how to make or source a wheeled mower deck.

Step one in this conversion was stripping all the paint off the deck and welding a plate over where the original gas engine was. [AmpEater] then 3D printed some mounts to hold the DeWalt tool batteries he would be using as a power source, taking the extra time to align everything so it would have the look of an old flathead gasoline engine. A tongue-in-cheek reference to the mower’s old gasoline gulping days, and an awesome little detail that gives the final product a great look.

The controller is a commercial model intended for electric bikes, and the heart of this new mower is a brushless direct-drive motor capable of 3,000 RPM at 40 A. [AmpEater] reports a respectable one hour run time with the six DeWalt batteries, and more power than his store-bought Ryobi electric mower.

If the name [AmpEater] looks familiar, it’s because this isn’t the first time he’s graced us with a mower conversion: back in 2013 he impressed us with his solar-electric Cub Cadet zero-turn. This build isn’t quite as slick as the Cub Cadet, but the much lower cost and difficulty level means that you may be able to follow in his footsteps even if you don’t have his Zeus-level mastery of the electric motor.

As electric mowers have gotten more popular, we’ve seen an increasing flow of hacks and mods for them. Everything from replacing the batteries to turning them into something else completely.

Biometric Authentication With A Cheap USB Hub

December 7, 2017 by 26 Comments

It’s fair to say that fingerprints aren’t necessarily the best idea for device authentication, after all, they’re kind of everywhere. But in some cases, such as a device that never leaves your home, fingerprints are an appealing way to speed up repetitive logins. Unfortunately, fingerprint scanners aren’t exactly ubiquitous pieces of hardware yet. We wouldn’t hold out much hope for seeing a future Raspberry Pi with a fingerprint scanner sitting on top, for example.

Looking for a cheap way to add fingerprint scanning capabilities to his devices, [Nicholas] came up with a clever solution that is not only inexpensive, but multi-functional. By combining a cheap USB hub with a fingerprint scanner that was intended as a replacement part of a Thinkpad laptop, he was able to put together a biometric USB hub for around $5 USD.

After buying the Thinkpad fingerprint scanner, he wanted to make sure it would be detected by his computer as a standard USB device. The connector and pinout on the scanner aren’t standard, so he had to scrape off the plastic coating of the ribbon cable and do some probing with his multimeter to figure out what went where. Luckily, once he found the ground wire, the order of the rest of the connections were unchanged from normal USB.

When connected to up his Ubuntu machine, the Thinkpad scanner came up as a “STMicroelectronics Fingerprint Reader”, and could be configured with libpam-fprintd.

With the pintout and software configuration now known, all that was left was getting it integrated into the USB hub. One of the hub’s ports was removed and filled in with hot glue, and the fingerprint scanner connected in its place. A hole was then cut in the case of the hub for the scanner to peak out of. [Nicholas] mentions his Dremel is on loan to somebody else at the moment, and says he’ll probably try to clean the case and opening up a bit when he gets it back.

[Nicholas] was actually inspired to tackle this project based on a Hackaday post he read awhile back, so this one has truly come full circle. If you’d like to learn more about fingerprint scanning and the techniques being developed to improve it, we’ve got some excellent articles to get you started.

DIY Wooden Building Blocks

December 7, 2017 by 15 Comments

If you have access to a drill press, saw, and sander, and are looking for a great present for smaller children this holiday season, [Jonny] may have you covered. He’s come up with a pretty good how to on making some simple block and dowel building blocks similar to the Tinkertoy building sets.

This is a fairly simple build if you have the shop tools, and if you only have hand tools available, is still quite doable. The blocks consist of square wooden blocks with holes drilled into them and a bunch of wooden dowels cut to size. [Jonny] adds a wooden box with a hinged lid for storing the blocks in as an added feature of the build,.

There are no LEDs lighting up, no Arduino-powered microcontroller involved, and they don’t connect to the internet, but that doesn’t make them any less of a great toy. Even without the shop tools, these could be made pretty quickly even by someone without prior experience with woodworking. If you’re interested in building block toys, check out this write-up about a way to combine different types of building blocks together, or check out this write-up about creating the frame of a DIY CNC mill with a metal building set.

Continue reading “DIY Wooden Building Blocks” →

Hands On With PocketBeagle

December 7, 2017 by 31 Comments

[Ken Shirriff] is no stranger to the pages of Hackaday. His blog posts are always interesting, and the recent one talking about the PocketBeagle is no exception. If you are old enough to remember the days when a Unix workstation set you back tens of thousands of dollars, you won’t be able to help yourself marveling at a Linux computer with 45 I/O pins, 8 analog inputs, 512M of RAM, and a 1 GHz clock, that fits in your pocket and costs $25. What’s more the board’s CPU has two 200 MHz auxiliary CPUs onboard to handle I/O without having to worry about Linux overhead.

These last parts are significant, and although the Beagles have had this feature for years ([Ken] talked about it earlier), the access and communication methods for using these slave processors has become easier. [Ken] shows a small snippet of C code that outputs a 40 MHz square wave no matter what the Linux OS is doing. In this way you can use Linux for the parts of your application that are not that critical, and use the slave processors to handle real time processing.

Continue reading “Hands On With PocketBeagle” →

Another Defeat Of The Intel Management Engine

December 7, 2017 by 53 Comments

If you have a computer with an Intel processor that’s newer than about 2007, odds are high that it also contains a mystery software package known as the Intel Management Engine (ME). The ME has complete access to the computer below the operating system and can access a network, the computer’s memory, and many other parts of the computer even when the computer is powered down. If you’re thinking that this seems like an incredible security vulnerability then you’re not alone, and a team at Black Hat Europe 2017 has demonstrated yet another flaw in this black box (PDF), allowing arbitrary code execution and bypassing many of the known ME protections.

[Mark Ermolov] and [Maxim Goryachy] are the two-man team that discovered this exploit, only the second of its kind in the 12 years that the ME has been deployed. Luckily, this exploit can’t be taken advantage of (yet) unless an attacker has physical access to the device. Intel’s firmware upgrades also do not solve the problem because the patches still allow for use of older versions of the ME. [Mark] and [Maxim] speculate in their presentation that this might be fixed on the next version of the ME, but also note that these security vulnerabilities would disappear if Intel would stop shipping processors with the ME.

We won’t hold our breath on Intel doing the right thing by eliminating the ME, though. It’s only a matter of time before someone discovers a zero-day (if they haven’t already, there’s no way to know) which could cripple pretty much every computer built within the last ten years. If you’re OK with using legacy hardware, though, it is possible to eliminate the management engine and have a computer that doesn’t have crippling security vulnerabilities built into it. This post was even written from one. Good luck doing anything more resource-intensive with it, though.

Alan Yates: Introduction To Vacuum Technology

December 7, 2017 by 17 Comments

When we mention vacuum technology, it’s not impossible that many of you will instantly turn your minds to vacuum tubes, and think about triodes, or pentodes. But while there is a lot to interest the curious in the electronics of yesteryear, they are not the only facet of vacuum technology that should capture your attention.

When [Alan Yates] gave his talk at the 2017 Hackaday Superconference entitled “Introduction To Vacuum Technology”, he was speaking in a much more literal sense. Instead of a technology that happens to use a vacuum, his subject was the technologies surrounding working with vacuums; examining the equipment and terminology surrounding them while remaining within the bounds of what is possible for the experimenter. You can watch it yourself below the break, or read on for our precis.

In the first instance, he introduces us to the concept of a vacuum, starting with the work of [Evangelista Torricelli] on mercury barometers in the 17th century Italy, and continuing to explain how pressure, and thus vacuum, is quantified. Along the way, he informs us that a Pascal can be explained in layman’s terms as roughly the pressure exerted by an American dollar bill on the hand of someone holding it, and introduces us to a few legacy units of vacuum measurement.

In classifying the different types of vacuum he starts with weak vacuum sources such as a domestic vacuum cleaner and goes on to say that the vacuum he’s dealing with is classified as medium, between 3kPa and 100mPa. Higher vacuum is beyond the capabilities of the equipment available outside high-end laboratories.

Introduction over, he starts on the subject of equipment with a quick word about safety, before giving an overview of the components a typical small-scale vacuum experimenter’s set-up. We see the different types of vacuum gauges, we’re introduced to two different types of service pumps for air conditioning engineers, and we learn about vacuum manifolds. Tips such as smelling the oil in a vacuum pump to assess its quality are mentioned, and how to make a simple mist trap for a cheaper pump. There is a fascinating description of the more exotic pumps for higher vacuums, even though these will be out of reach of the experimenter it is still of great interest to have some exposure to them. He takes us through vacuum chambers, with a warning against cheap bell jars not intended for vacuum use, but suggests that some preserving jars can make an adequate chamber.

We are then introduced to home-made gas discharge tubes, showing us a home-made one that lights up simply by proximity to a high voltage source. Something as simple as one of the cheap Tesla coil kits to be found online can be enough to excite these tubes, giving a simple project for the vacuum experimenter that delivers quick results.

Finally, we’re taken through some of the tools and sundries of the vacuum experimenter, the different types of gas torches for glass work, and consumables such as vacuum grease. Some of them aren’t cheap, but notwithstanding those, he shows us that vacuum experiments can be made within a reasonable budget.

Continue reading “Alan Yates: Introduction To Vacuum Technology” →