Making A Metal Hand Doorknob

September 24, 2021 by Zoe Skyforest 23 Comments

Regular doorknobs are widely reviled for their bare simplicity, but by and large society has so many other problems that it never really comes up in day to day conversation. Fear not, however, for [Matthew] has created something altogether more special: a doorknob in the shape of his own outstretched hand.

The build was inspired by a similar doorknob at the WNDR museum in Chicago, and its one you can recreate yourself, too. It’s achieved through a multi-stage mold making process. [Matthew]’s first step was to make a flexible mold of his hand using Perfect Mold alginate material to do so.

Once solidified, [Matthew’s] hand was removed and the mold filled with wax. The wax duplicate of [Matthew]’s hand was then used to create an investment plaster mold for casting metal. Vents were added in the end of each fingertip in the mold to allow molten metal to effectively fill the entire cavity.

Once the investment mold was solid and dry, the wax was melted out and it was ready for casting. A propane furnace was used to melt the casting metal and fill the mold using a simple gravity casting method. [Matthew] ended up making two hands, one in aluminium and one in copper. Some cleanup with grinders and a wire wheel, and a replica of [Matthew]’s hand was in his hands!

The finished piece looks great attached to a door knob, and we’re sure it’s quite satisfying shaking hands with your hefty metal self every time you open the door. It bears noting that the same techniques can be used with 3D printing, too! If you pull off your own great home casting project, be sure to drop us a line. Video after the break.

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Rescuing A Wacom Digitizer From A Broken Lenovo Yoga Book

September 23, 2021 by Zoe Skyforest 5 Comments

The Lenovo Yoga Book is a interesting thing, featuring a touch-surface keyboard that also doubles as a Wacom tablet. [TinLethax] sadly broke the glass of this keyboard when trying to replace a battery in their Yoga Book, but realised the Wacom digitizer was still intact. Thus began a project to salvage this part and repurpose it for the future.

The first step was to reverse engineer the hardware; as it turns out, the digitizer pad connects to a special Wacom W9013 chip which holds the company’s secret sauce (secret smoke?). As the GitHub page for [TinLethax]’s WacomRipoff driver explains, however, the chip communicates over I2C. Thus, it was a simple enough job to hook up a microcontroller, in this case an STM32 part, and then spit out USB HID data to a host.

It hasn’t all been smooth sailing, and it’s not 100% feature complete, but [TinLethax] was able to get the digitizer working as a USB HID input device. It appears the buttons and pressure sensitivity are functional, too.

If you’ve got a disused or defunct Yoga Book lying around, you might just consider the same mods yourself. We’ve seen some other great hacks in this space, too. Video after the break.

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Bluetooth Vulnerability: Arbitrary Code Execution On The ESP32, Among Others

September 23, 2021 by Zoe Skyforest 21 Comments

Bluetooth has become widely popular since its introduction in 1999. However, it’s also had its fair share of security problems over the years. Just recently, a research group from the Singapore University of Technology and Design found a serious vulnerability in a large variety of Bluetooth devices. Having now been disclosed, it is known as the BrakTooth vulnerability.

Full details are not yet available; the research team is waiting until October to publicly release proof-of-concept code in order to give time for companies to patch their devices. The basic idea however, is in the name. “Brak” is the Norweigan word for “crash,” with “tooth” referring to Bluetooth itself. The attack involves repeatedly attempting to crash devices to force them into undesired operation.

The Espressif ESP32 is perhaps one of the worst affected. Found in all manner of IoT devices, the ESP32 can be fooled into executing arbitrary code via this vulnerability, which can do everything from clearing the devices RAM to flipping GPIO pins. In smart home applications or other security-critical situations, this could have dire consequences.

Other chipsets are affected to varying degrees, including parts from manufacturers like Texas Instruments and Cypress Semiconductor. Some parts are vulnerable to denial of service, while audio devices may be frozen up or shut down by the attack. The group claims over 1400 products could be affected by the bug.

Firmware patches are being rolled out, and researcher [Matheus E. Garbelini] has released code to build a sniffer device for the vulnerability on GitHub. If you’re involved with the design or manufacture of Bluetooth hardware, it might pay to start doing some homework on this one! Concerned vendors can apply for proof-of-concept test code here.

Even Faster Fourier Transforms On The Raspbery Pi Zero

September 22, 2021 by Zoe Skyforest 7 Comments

Oftentimes in computing, we start doing a thing, and we’re glad we’re doing it. But then we realise, it would be much nicer if we could do it much faster. [Ricardo de Azambuja] was in just such a situation when working with the Raspberry Pi Zero, and realised that there were some techniques that could drastically speed up Fast Fourier Transforms (FFT) on the platform. Thus, he got to work.

The trick is using the Raspberry Pi Zero’s GPU to handle the FFTs instead of the CPU itself. This netted Ricardo a 7x speed upgrade for 1-dimensional FFTs, and a 2x speed upgrade for 2-dimensional operations.

The idea was cribbed from work we featured many years ago, which provided a similar speed up to the very first Raspberry Pi. Given the Pi Zero uses the same SoC as the original Raspberry Pi but at a higher clock rate, this makes perfect sense. However, in this case, [Ricardo] implemented the code in Python instead of C as suits his use case.

[Ricardo] uses the code with his Maple Syrup Pi Camera project, which pairs a Coral USB machine learning accelerator with a Pi Zero and a camera to achieve tasks such as automatic licence plate recognition or facemask detection. Fun!

An Entirely Frivolous Way To Measure Data

September 22, 2021 by Zoe Skyforest 23 Comments

[lexie] is a librarian, and librarians live in the real world. They’re not concerned with vague digital notions about the size of data, but practical notions of space. Thus, she created a tool to answer an important question: how long do your shelves need to be if you’re storing all your information on 3.5″ floppy disks?

It’s a great question, and one we find ourselves asking, well, pretty much never. [lexie]’s tool is also built using modern web technologies, and 3.5″ floppy disks were never really used for bulk storage, either. It just makes the whole thing all the more frivolous, and that makes it more fun.

You can key in any quantity from megabytes to exabytes and the tool will spit out the relevant answer in anything from millimeters to miles as appropriate. Despite the graphics on the web page, it does assume rational shelving practices of placing disks along the shelves on their thinner 4 mm edge.

We’d love to see a expanded version that covers other storage methods, like tape, hard drives, or burnt media. It could actually become pretty useful for those building their own mass storage farms at home. With CHIA cryptocurrency that could become more popular, even if it does run us all out of hard drives along the way. Altnernatively, you might consider hooking up a floppy controller for your Raspberry Pi.

Building A Custom Linux Single Board Computer Just To Play Spotify

September 22, 2021 by Zoe Skyforest 31 Comments

If you want to hook up an existing stereo or amplifier to Spotify, there’s a fair few options on the market. You can even just order a Raspberry Pi and be done with it. [Evan Hailey] went his own way, however, and built his own Spotify Box from scratch.

[Evan] even made this tidy wooden enclosure, learning yet more along the way!

Housed inside a tidy little wooden enclosure of his own creation, the Spotify Box can turn any amplifier into a remote-controlled Spotify player via Spotify Connect. Pick the songs on your smartphone, and they’ll play from the Spotify Box as simple as that.

The project is based on the Allwinner V3S, a system-on-chip with a 1.2GHz ARM-Cortex-A7 core, 64MB of DDR2 RAM, and an Ethernet transceiver for good measure. There’s also a high-quality audio codec built in, making it perfect for this application. It’s thrown onto a four-layer PCB of [Evan’s] own design, and paired with a Wi-Fi and BlueTooth transceiver, RJ-45 and RCA jacks, a push-button and some LEDs. There’s also an SD card for storage.

With a custom Linux install brewed up using Buildroot, [Evan] was able to get a barebones system running Spotifyd while communicating with the network. With that done, it was as simple as hooking up the Spotify Box to an amp and grooving out to some tunes.

Along the way, [Evan] learned all about compiling drivers and working with embedded Linux, as well as how to take a bare SoC and build it into a fully-functional single-board computer. When someone else says they “made” a Spotify player, he presumably gets to clear his throat.

If you fancy retro computers, consider interfacing Spotify with your classic Mac instead!

[Thanks to Jay Carlson for the tip!]

Spooky Coffin Bell Spooks Passers By On Halloween

September 21, 2021 by Zoe Skyforest 3 Comments

Being buried alive isn’t fun, we imagine. Fear of it led to the development of various safety coffin ideas in the 18th and 19th centuries, and [Glen Akins] wonderful Halloween prop riffs on that tradition today.

The safety coffin was a simple solution for those afraid that this might happen to them. One concept had a bell which was installed above freshly dug graves with a string extending into the coffin. One who found themselves accidentally buried alive could then pull the string to ring the bell and summon help.

[Glen’s] installation eliminates the coffin and the dead body, and simply mounts a bell on a post. Inside, there’s an ultrasonic rangefinder that detects passers by. When someone walks closely enough to the prop, a microcontroller triggers a servo which rings the bell with a haunting urgency.

It’s a simple build, but appropriately installed with its LED lighting, it really does pop. It would be a wonderful way to add atmosphere and mood to a Hallowe’en party or haunted house. We’ve seen some great Hallowe’en hacks over the years, and some of the best are pumpkins. Video after the break.

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