Cheap DIY High Impedance Earphones

December 3, 2020 by Zoe Skyforest 18 Comments

Crystal radios can feel magical, given their ability to tune in audio from distant stations with nothing but the energy from the radio signal itself. However, to achieve this feat, they typically rely on a high-impedance earphone to produce an audible sound with very little current. These earphones are hard to find, and thus can be expensive. However, [Billy] figured out a way to build them on the cheap.

The build starts with a common piezoelectric buzzer. It’s torn down and the extraneous circuitry inside is removed. The piezo element itself is then directly hooked up to a mono audio jack for use with one of [Billy’s] crystal radios. To make it into a usable earpiece, the tip of a pen is cut off and glued to the buzzer’s plastic housing. Then, a rubber in-ear cup from regular modern earbuds is used to ensure a tight, comfortable fit in the ear.

It’s a great way to build something that’s now hard to source, and we bet that [Billy’s] design is more comfortable than the hard plastic models that shipped in Radio Shack kits in the 90s. Of course, there’s other ways to build high-impedance drivers, as we’ve featured before. And, if you’re looking to build a crystal radio, it’s hard to go past [Billy’s] credit card chip build. Video after the break.

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Watercooling A Canon DSLR Leads To Serious Engineering Upgrades

December 1, 2020 by Zoe Skyforest 55 Comments

The Canon EOS R5 is a highly capable, and correspondingly very expensive camera. Capable of recording video in 8K in a compact frame size, it unfortunately suffers from frustrating overheating issues. Always one to try an unconventional solution to a common problem, [Matt] decided to whip up a watercooling solution. What ensues is pure, top-notch engineering.

The watercooling setup is amusing, but the real star of the show is the custom copper heatsink that transforms the camera’s performance without spoiling its practicality.

Upon its original release, Canon had the R5 camera simply shut off on a 20 minute timer when recording 8K video. When the userbase complained, an updated firmware was released that used an onboard sensor and would only shutdown when excessive temperatures were reached. Under these conditions, the camera could record for around 25 minutes at 20 °C. [Matt] set about disassembling the camera to investigate, figuring out that the main processor was the primary source of heat. With a poor connection to its heatsink and buried under a power supply PCB, there simply wasn’t anywhere for heat to go, leaving the camera to regularly overheat and take hours to cool down.

After whipping up an amusing but impractical watercooling solution and verifying it allowed the camera to record indefinitely, [Matt] set about some proper thermal engineering. A custom copper heatsink was produced for inside the camera, bonded directly to the processor and DRAM with thermal paste instead of poor-quality thermal tape. This then directs heat out through the plastic back of the camera. In cool environments, this is enough to allow the camera to record continuously. In warmer environments, simply adding a small fan to the back of the camera was enough to keep things operational indefinitely.

[Matt] finishes the video by pointing out that Canon could have made the camera far more useful for videographers by simply investing a little more time into the camera’s cooling design, while also generating more profits by selling a cooling accessory for extended recording. We’ve seen some of [Matt’s] work before too, such as this DIY 4K projector build. Video after the break.

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Let’s Encrypt Will Stop Working For Older Android Devices

December 1, 2020 by Zoe Skyforest 20 Comments

Let’s Encrypt was founded in 2012, going public in 2014, with the aim to improve security on the web. The goal was to be achieved by providing free, automated access to SSL and TLS certificates that would allow websites to make the switch over to HTTPS without having to spend any money.

Hundreds of millions of sites rely on Let’s Encrypt for their HTTPS certificate needs. HTTPS security helps protect sites and users, and makes it harder for malicious actors to steal private information.

The project has just announced that, come September 1, 2021, some older software will stop trusting their certificates. Let’s look at why this has come to pass, and what it means going forward.

Certificates Expire

When Let’s Encrypt first went public in early 2016, they issued their own root certificate, by the name ISRG Root X1. However, it takes time for companies to include updated root certificates in their software, so until recently, all Let’s Encrypt certificates were cross-signed by an IdenTrust certificate, DST Root X3. This certificate had been around much longer, and was already supported by the vast majority of OSes and browsers in regular use. This allowed Let’s Encrypt to hit the ground running while they waited for the majority of software to support their own root certificate. Continue reading “Let’s Encrypt Will Stop Working For Older Android Devices” →

Building A Dishwasher From Scratch

November 30, 2020 by Zoe Skyforest 49 Comments

[Billy] was no fan of doing the dishes, but also found commercial solutions lacking. The options on the market simply didn’t fit his cookware and flatware. Instead of compromising, he set out to build a dishwasher of his own design.

The build consists of a whole heap of hardware all lumped in a sizeable plastic tub. A washing machine solenoid lets water into the system, and it’s heated by an element in the base of the tub. It’s then pumped through a garden sprinkler head to give the dishes a good all-over spraying. At the end of a wash cycle, the drain pump then dumps the water to let everything dry off. An ESP8266 and a bank of relays are in place to run the show, with the user selecting wash programs via buttons and a small screen.

It may have taken a couple of years to come together, but [Billy’s] dishwasher seems to get the job done. Files are on Github for those interested, however we’d caution against attempting such a build unless you’re familiar working with plumbing and mains electricity. The other benefit of building your own dishwasher is that you’re less likely to have to patch it against widespread exploits – the security is instead up to you. Video after the break.

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Leaking Data Slowly By Switching Ethernet Speeds

November 30, 2020 by Zoe Skyforest 9 Comments

Airgapping refers to running a machine or machines without connections to external networks. Literally, a gap of air exists between the machine and the outside world. These measures present a challenge to those wishing to exfiltrate data from such a machine, leading to some creative hacks. [Jacek] has recently been experimenting with leaking data via Ethernet adapters.

The hack builds on [Jacek]’s earlier work with the Raspberry Pi 4, in which the onboard adapter is rapidly switched between 10 and 100 Megabit modes to create a signal that can be picked up via radio up to 100 meters away. Since then, [Jacek] determined the Raspberry Pi 4, or at least his particular one, seems to be very leaky of RF energy from the Ethernet port. He decided to delve deeper by trying the same hack out on other hardware.

Using a pair of Dell laptops connected back to back with an Ethernet cable, the same speed-switching trick was employed. However, most hardware takes longer to switch speeds than the Pi 4; usually on the order of 2-5 seconds. This limited the signalling speed, but [Jacek] was able to set this up to exfiltrate data using QRSS, also known as very slow speed Morse code. The best result was picking up a signal from 10 meters away, although [Jacek] suspects this could be improved with better antenna hardware.

While slow data rates and the one-way nature of such communication limit the utility of such an attack, it nonetheless shows that securing a machine isn’t as simple as unplugging it from the network. We’ve done a feature on such hacks before for those interested in learning more. Video after the break.

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Mouse-Controlled Mouse Controller Is Silly, But Could Be Useful

November 29, 2020 by Zoe Skyforest 19 Comments

Useless machines are generally built as a fun pastime, as they do nothing of value by their very definition. The most popular type generally involves a self-cancelling switch. However, there’s plenty of other useless machines to build, and we think [Jeffery’s] build is particularly creative.

The build consists of an XY gantry that moves a standard computer mouse. To control the gantry, a Raspberry Pi feeds the system G-Code relative to the motion of a second mouse plugged into the single-board computer. It’s pretty standard fare overall, with the Pi sending commands to an Arduino that runs the various stepper motors via a CNC controller shield.

Yes, it’s a mouse that moves a mouse – and on the surface, this appears to be a very useless machine. However, we could imagine it being useful for remote control of a very old system that uses a non-standard mouse that is otherwise difficult to emulate. Additionally, it wouldn’t take much extra work to turn the XY gantry into a competent pen-plotter – of which we’ve seen many. Video after the break.

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Calendar Printer Makes You A Hard Copy On The Daily

November 29, 2020 by Zoe Skyforest 9 Comments

We’re blessed to have cloud-based calendars that store all the relevant data on our hyper-busy lives for easy access anywhere and everywhere. However, sometimes a hard copy is nice for when you’re tired of looking at screens. In this vein, [lokthelok] produced a compact device that prints out your schedule on the daily.

The device uses an ESP32 to connect to WiFi, and then query Google Apps for a given user’s calendar details on a daily basis. After grabbing the data, it’s fed out to a thermal printer connected over serial at 9600 baud. As a twist, [lokthelok] has produced two versions of firmware for the project. The master version simply scrapes calendar data and outputs it neatly. The Useless version goes further, jumbling up appointments and printing them out of order. If you’ve got nothing on for the day, it will instead spool out the remainder of the thermal paper on the roll.

It’s a build that would make a handsome desk toy, though we suspect tossing out each day’s calendar could become tiresome after a while. Alternatively, consider a clock that highlights your upcoming events for you. Video after the break.

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