Hackaday Links: October 31, 2021

October 31, 2021 by Dan Maloney 17 Comments

Global supply chain issues are beginning to hit closer to home for the hacker community, as Raspberry Pi has announced their first-ever price increase on their flagship Pi 4. The move essentially undoes the price drop on the 2GB version of the Pi 4 that was announced in February, and sets the price back up from $35 to $45. Also rolled back is the discontinuation of the 1GB version, which will now be available at the $35 price point. The announcements come from Eben Upton himself, who insists the price increase is only temporary. We applaud his optimism, but take it with a grain of salt since he also said that 2021 production across the board will stay at the seven million-unit level, which is what they produced in 2020. That seems to speak to deeper issues within the supply chain, but more immediately, it’s likely that the supply of Pi products will be pinched enough that you’ll end up paying above sticker price just to get the boards you need. Hope everyone is stocked up.

On the topic of supply chain issues and their threat to Christmas gift-giving, here’s one product we hope is stranded in a container off Long Beach or better still, bobbing along in the Strait of Juan De Fuca: a toddler’s toy telephone that actually makes and receives calls. Anyone born in the last 60 years probably had one of the Fisher-Price Chatter telephone, a toy that in its original form looked like a desk telephone on wheels that was dragged behind the child, popping along and providing endless hours of clicky amusement as kids twisted the dial and lifted the receiver. Come to think of it, the Chatter telephone may be as close to a dial phone as anyone born since 1990 may have come. Anyway, some genius stuck a Bluetooth module into the classic phone to let it hook up to an app on an actual phone, allowing kids (or more likely their nostalgia-soaked parents) to make and receive calls. It’s actually priced at a reasonable $60, so there might be some hacking potential here.

Also tangential to supply chains, we stumbled across a video guide to buying steel that might interest readers. Anyone who has seen the displays of steel and other metals at the usual big-box retailers might wonder what the fuss is, but buying steel that way or ordering online is a great way to bust a project’s budget. Fabricator and artist Doug Boyd insists that finding a local steel supplier is the best bang for your buck, and has a bunch of helpful tips for not sounding like a casual when you’re ordering. It’s all good advice, and would have helped us from looking foolish a time or two at the metal yard; just knowing that pipe is measured by inside diameter while tubing is measured by outside dimensions is worth the price of admission alone.

With all the money you save on steel and by not buying Raspberry Pis, perhaps you’ll have a couple of hundred thousand Euros lying around to bid on this authentic 1957 Sputnik I satellite. The full-scale model of Earth’s first artificial satellite — manhole covers excluded — was a non-flown test article, but externally faithful to the flown hardware that kicked off the first Space Race. The prospectus says that it has a transmitter and a “modern power supply”; it’s not clear if the transmitter was originally part of the test article or added later. The opening bid is €85,000 and is expected to climb considerably.

And finally, there’s something fascinating about “spy radios,” especially those from the Cold War era and before, when being caught with one in your possession was probably going to turn out to be a very bad day. One such radio is the Radio Orange “Acorn” receiver, which is in the collection of the Crypto Museum. The radio was used by the Dutch government to transmit news and information into the occupied Netherlands from their exile in London. Built to pass for a jewelry box, the case for the radio was made from an old cigar box and is a marvel of 1940s miniaturization. The radio used three acorn-style vacuum tubes and was powered by mains current; another version of the Radio Orange receiver was powered by a bike dynamo or even a water-powered turbine, which could be run from a tap or garden hose. The video below shows the water-powered version in action, but the racket it made must have been problematic for its users, especially given the stakes.

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Bring That Old Hi-Fi Into The 2020s

October 24, 2021 by Jenny List 41 Comments

It’s a distressing moment for some of us, when a formerly prized piece of electronic equipment reaches a point of obsolescence that we consider jettisoning it. [Jon Robinson] ran into this dilemma by finding the Kenwood Hi-Fi amplifier his 17-year-old self had spent his savings on. It was a very good amp back in the day, but over two decades later, it’s no longer an object of desire in a world of soundbars and streaming music boxes. After a earlier upgrade involving an Arduino to auto-power it he’s now given it an ESP32 and an i2S codec which performs the task of digital audio streaming as well as a better job than the Arduino of controlling the power.

Inside the case is a piece of stripboard with the ESP and codec modules, but there was still the problem of seamlessly integrating it with the amp’s distinctly analogue-era controls. The output from the codec is wired into an audio input – quaintly labelled for a DAT player – and a simple cam on the input selector switch operates a microswitch to select the ESP32.

If you’re dipping your toe in decent audio then an old amp from decades past can make an excellent purchase, but you might wish to educate yourself through our Know Audio series.

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

September 23, 2021 by Lewin Day 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.

Fan Lets RC Car Drive On The Ceiling

September 4, 2021 by Lewin Day 7 Comments

Downforce is a major part of modern motorsport, keeping cars glued to the track at high speeds. However, for small radio control cars, adding a fan for a little suction can achieve even greater feats, as demonstrated by this build by [DD ElectroTech].

The build began as a simple two-motor, skid-steer RC car build with a fan for suction. Controlled by a smartphone app, a cheap Arduino board with an HC-05 Bluetooth module ran the show. However, when this was all assembled, the car was too heavy to climb walls or stick to the ceiling.

Thus, a weight-saving plan was in order. Wheels were swapped out for lighter 3D printed parts. The electronics saw significant re-engineering, too, with the multiple separate modules all condensed down into one single custom PCB. After a few other tweaks, the new lighter car was able to easily drive on the ceiling and even climb walls, albeit with some difficulty.

It’s a fun little build and a good demonstration of how easy it is to whip up cool projects with modern electronics and 3D printed parts. We’ve seen other printed fan car builds before, too, but did you know the concept was first trialed in real-world motorsport competition? Video after the break.

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How To Modify Your Car Stereo For Bluetooth Or Aux-In

July 28, 2021 by Lewin Day 42 Comments

If you’re an automotive enthusiast of taste, you can’t stand the idea of fitting a janky aftermarket stereo into your nice, clean ride. Flashy, modern head units can spoil the look of a car’s interior, particularly if the car is a retro, classic, or vintage ride.

Thus, we’re going to look at how to modify your existing stock car stereo to accept an auxiliary cable input or even a Bluetooth module. This way, you can pump in the latest tunes from your smartphone without a fuss, while still maintaining an all-original look on the dash.

Fundamentals

A simple Bluetooth module designed for wiring into car audio systems. There are two wires for 12 V power from the vehicle, and the audio signal is sent out over the RCA plugs. The RCA plugs can be cut off and the module hard wired inside your stereo if you have room. Cutting off the plastic case can help too.

Depending on your choice of audio player, you may prefer a 3.5 mm aux jack, or you might want to go with Bluetooth audio if your smartphone no longer has a headphone port. Whichever way you go, the process of modifying the stereo is largely the same. To achieve your goal, you need to find a way of injecting the audio signal into the head unit’s amplifier stage, while making sure no other audio sources are getting sent there as well.

Whether that audio source is a 3.5 mm jack or a Bluetooth module doesn’t matter. The only difference is, in the latter case, you’ll want to buy a Bluetooth module and hardwire it in to the auxiliary input you create, while also splicing the module into the stereo’s power supply. In the case of a simple headphone jack input, you simply need to wire up an aux cord or 3.5 mm jack somewhere you can get to it, and call it done.

This guide won’t cover every stereo under the sun, of course. Edge cases exist and depending on the minute specifics of how your original car radio works, these exact methods may or may not work for you. However, this guide is intended to get you thinking conceptually about how such mods are done, so that you can investigate the hardware in front of you and make your own decisions about how to integrate an external audio input that suits your usage case. Continue reading “How To Modify Your Car Stereo For Bluetooth Or Aux-In” →

Vintage Remote Control Gets Bluetooth Upgrade

July 4, 2021 by Tom Nardi 20 Comments

This swanky Magnavox remote is old enough to predate the use of infrared, and actually relies on ultrasound to communicate with the television. It’s a neat conversation starter, but not terribly useful today. Which is why [Chad Lawson] decided to gut the original electronics and replace it with a Adafruit Feather 32u4 Bluefruit LE that can actually talk to modern devices.

We know, we know. Some in the audience will probably take offense to such a cool gadget being unceremoniously torn apart, but to be fair, [Chad] does say he has a second one that will remain in its original state. Plus a quick check on eBay shows these old remotes don’t seem to be particularly rare or valuable. In fact, after some browsing through the recently concluded auctions, we’re fairly sure he paid $27 USD for both of these remotes.

Anyway, [Chad] found that a piece of perfboard in his collection just happened to be nearly the same size as the PCB from the remote, which made the rest of the conversion pretty straightforward. He simply had to mount tactile switches on one side of the perfboard so the remote’s original buttons would hit them when pressed, and then wire those to the Adafruit on the other side. We know there’s a 3.7 V 500 mAh pouch battery in there someplace as well, though it’s not immediately clear where he hid it in the images.

The code [Chad] came up with tells the Adafruit to mimic a Bluetooth Human Interface Device (HID) and send standard key codes to whatever device pairs with it. That makes it easy to use as a media remote on the computer, for example. We’ve seen something similar done with the ESP32, if you’ve already got one in the parts bin and are looking to revamp a remote control of your own.

At the end of the write-up, [Chad] mentions he may try developing an ultrasonic receiver that can pick up the signals from the unmodified remote control. That would be a nice way to bring this whole thing full circle, and should appease even the most hardcore vintage remote control aficionados.

DOOM Comes To The NRF5340

June 22, 2021 by Tom Nardi 14 Comments

If you’re looking for a reminder of how powerful the tiny microcontrollers that run our everyday gadgets have become, check out the work impressive work [Audun Wilhelmsen] has done to get DOOM running on the Nordic Semiconductor nRF5340. This is the sort of Bluetooth SoC you’d expect to find in a headset or wireless keyboard, and yet it’s packing a 128 MHz processor that can go head to head with the Intel 486 that the iconic first person shooter recommended you have in your old beige box PC.

That said, porting the open source shooter over to the nRF5340 wasn’t exactly easy. The challenge was getting the game, which recommended your PC have 8 MB back in 1993, to run on a microcontroller with a paltry 512 KB of memory. Luckily, a lot of the data the game loads into RAM is static. While that might have been necessary when the game was running from a pokey IDE hard drive, the nearly instantaneous access times of solid state storage and the nRF5340’s execute in place (XIP) capability meant [Audun] could move all of that over to an SPI-connected 8 MB flash chip with some tweaks to the code.

In general, [Audun] explains that many of the design decisions made for the original DOOM engine were made with the assumption that the limiting factor would be CPU power rather than RAM. So that lead to things often getting pre-calculated and stored in memory for instant access. But with the extra horsepower of the nRF5340, it was often helpful to flip this dynamic over and reverse the optimizations made by the original developers.

On the hardware side, things are relatively straightforward. The 4.3″ 800×480 LCD display is connected over SPI, and an I2S DAC handles the sound. Bluetooth would have been the logical choice for the controls, but to keep things simple, [Audun] ended up using a BBC micro:bit that could communicate with the nRF5340 via Nordic’s own proprietary protocol. Though he does note that Bluetooth mouse and keyboard support is something he’d like to implement eventually.

If some of the software tricks employed by this hack sounded familiar, it’s because a very similar technique was used to get DOOM running on an IKEA TRÅDFRI light bulb a week or so back. Unfortunately it must have ruffled some feathers, as it was pulled from the Internet in short order. It sounds like [Audun] got the OK from his bosses at Nordic Semiconductor to go public with this project, so hopefully this one will stick around for awhile.

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