Author: Jenny List

3537 Articles

There’s Life In That Beard Trimmer Yet!

November 23, 2019 by 33 Comments

You just can’t get a decent beard trimmer these days! At least that’s what [Peter Franck] found when his trusty Panasonic finally expired after a couple of decades and a few replacement batteries. The shaver’s PCB contained a mains-powered NiCd charger which had comprehensively released its magic smoke, and the expensive replacement trimmers he bought simply didn’t cut the mustard.

Many people would have given up in despair, but he persevered, and produced a custom replacement board containing a Maxim DS2710 single-sell NiMH charger, and an AA NiMH cell. It fits perfectly into the space vacated by the previous board, and takes its charge through a micro-USB socket on the edge of the PCB.

It’s interesting to note that NiMH-based projects have in recent years become a comparative rarity on these pages compared to ones using Li-ion or Li-poly cells. This is an inevitable progression on cost, size, and power density grounds, but it’s still worth knowing about projects using the older battery chemistry. He remarks that his razor is now future-proofed, but we’d probably have fitted a USB-C conector before making that assertion. Either way, it’s a neat piece of work that has achieved its aim of making an expired razor useful again. We’ve brought you another razor fix in the past, though a much less sophisticated one.

A Tiny Terminal For Your Serial Access Needs

November 22, 2019 by 3 Comments

Some pieces of computing equipment have faded away without a trace, for example a modem is not a device that detains many hackers as they strive for that perfect emulation of a venerable Hayes on an Arduino. But there are some other devices that continue to hold a fascination, even years after they departed from the professional arena. A great example is the serial terminal. Once to be found on many a desk as it provided a way into a minicomputer, it has long ago been supplanted by terminal emulators or simply other portals into computing services such as the web. But in our community there are still plenty of serial terminals to be found, for example [RedHog]’s little emulated VT220 on an ESP8266 platform.

If you were hoping for a full-green screen and keyboard to plug into a hefty D-connector serial port then you’ll be a bit disappointed, as with a tiny screen and only a few buttons on a dev board or an Arduboy it’s not going to allow any 1337 vi mastery even with its on-screen keyboard. Take a look, we’ve placed a video below the  break. But despite all that it shows promise, with ability to use either the logic-level serial port or the USB serial interface. We can see that it might find a use as a serial display though, but it would fascinate us to see what could be done were it to use the 8266’s on-board WiFi in some form. If you’d like to experiment you can do so with the code on GitHub.

This isn’t the first such terminal we’ve seen here before of course, some of them have been extremely practical, while others we just want to own because they’re cool.

Continue reading “A Tiny Terminal For Your Serial Access Needs” →

Retrotechtacular: 934 MHz CB Radio

November 21, 2019 by 49 Comments

The radio spectrum is carefully regulated and divided up by Governments worldwide. Some of it is shared across jurisdictions under the terms of international treaties, while other allocations exist only in individual countries. Often these can contain some surprising oddities, and one of these is our subject today. Did you know that the UK’s first legal CB radio channels included a set in the UHF range, at 934 MHz? Don’t worry, neither did most Brits. Behind it lies a tale of bureaucracy, and of a bungled attempt to create an industry around a barely usable product.

Hey, 2019, Got Your Ears On?

Did this car make you want a CB radio? Stuurm [CC BY-SA 3.0]
Did this car make you want a CB radio? Stuurm [CC BY-SA 3.0]
Mention CB radio in 2019 it’s likely that the image conjured in the mind of the listener will be one from a previous decade. Burt Reynolds and Jerry Reed in Smokey and the Bandit perhaps, or C. W. McCall’s Convoy. It may not be very cool in the age of WhatsApp, but in the 1970s a CB rig was the last word in fashionable auto accessories and a serious object of desire into which otherwise sane adults yearned to speak the slang of the long-haul trucker.

If you weren’t American though, CB could be a risky business. Much of the rest of the world didn’t have a legal CB allocation, and correspondingly didn’t have access to legal CB rigs. The bombardment of CB references in exported American culture created a huge demand for CB though, and for British would-be CBers that was satisfied by illegally imported American equipment. A vibrant community erupted around UK illegal 27 MHz AM CB in the late 1970s, and Government anger was met with campaigning for a legal allocation. Brits eventually got a legal 27 MHz allocation in November 1981, but the years leading up to that produced a few surprises.

Continue reading “Retrotechtacular: 934 MHz CB Radio” →

There’s More To Designing A PCB Business Card Than Meets The Eye

November 19, 2019 by 9 Comments

A curious custom that survives from the pre-computer era is that of the business card. If you walk the halls at a trade event you’ll come a way with a stack of these, each bearing the contact details of someone you’ve encountered, and each in a world of social media and online contact destined to languish in some dusty corner of your desk. In the 21st century, when electronic contacts harvested by a mobile phone have the sticking power, how can a piece of card with its roots in a bygone era hope to compete?

It’s a question [Anthony Kouttron] has addressed in the design of his thoroughly modern business card, and along the way he’s treated us to an interesting narrative on how to make the card both useful beyond mere contact details as well as delivering that electronic contact. The resulting card has an array of  rulers and footprints as an electronic designer’s aid, as well as an NFC antenna and chip that lights an LED and delivers his website address when scanned. There are some small compromises such as PCB pads under the NFC antenna, but as he explains in the video below, they aren’t enough to stop it working. He’s put his work in a GitHub repository, should you wish to do something similar.

There’s a rich vein of business card projects on these pages, but so far surprisingly few are NFC equipped. That didn’t stop someone from making an NFC-enabled card with user interaction though.

Continue reading “There’s More To Designing A PCB Business Card Than Meets The Eye” →

Add A Bit Of PCB Badge Glamour To Your Boring ID Badge

November 18, 2019 by 6 Comments

When we talk about badges and printed circuit boards, it is usually in the context of the infinite creativity of the Badgelife scene, our community’s own art form of electronic conference badges. It’s easy to forget when homing in on those badges that there are other types of badge, and thus [Saimon]’s PCB badge holder is an entertaining deviation from our norm. His workplace requires employees to carry their credit-card-sized ID pass with them at all times, but the plastic holder that came with his had broken. So he did what any self-respecting engineer would do, and designed his own holder using PCBs.

It’s a three-way sandwich with identical front and back PCBs featuring a nice design, but the clever bit is the middle PCB. It is U-shaped to slide the card in from the side, but to retain the card it has a couple of springy milled PCB arms each with a small retaining tooth on the end. This is an ingenious solution, with just enough give to bend, but not so much as to break.

The three boards are glued together, it seems his original aim was to reflow solder them but this was not successful. The result is an attractive and functional badge holder, which if Hackaday required us to have a corporate ID you can be sure we’d be eyeing up for ourselves.

UNIX Version 0, Running On A PDP-7, In 2019

November 17, 2019 by 34 Comments

WIth the 50th birthday of the UNIX operating system being in the news of late, there has been a bit of a spotlight shone upon its earliest origins. At the Living Computers museum in Seattle though they’ve gone well beyond a bit of historical inquiry though, because they’ve had UNIX (or should we in this context say unix instead?) version 0 running on a DEC PDP-7 minicomputer. This primordial version on the original hardware is all the more remarkable because unlike its younger siblings very few PDP-7s have survived.

The machine running UNIX version 0 belongs to [Fred Yearian], a former Boeing engineer who bought his machine from the company’s surplus channel at the end of the 1970s. He restored it to working order and it sat in his basement for decades, while the vintage computing world labored under the impression that including the museum’s existing machine only four had survived — of which only one worked. [Fred’s] unexpected appearance with a potentially working fifth machine, therefore, came as something of a surprise.

To load the OS a disk emulator was connected to the machine, and for possibly the first time in many decades a new UNIX version 0 device driver was written to enable it to be used. The first login was the user “dmr”, a homage to UNIX co-creator Dennis M. Ritchie.

Continue reading “UNIX Version 0, Running On A PDP-7, In 2019” →

The ESP32, Laid Bare

November 17, 2019 by 31 Comments

Most readers will be familiar with the ESP32, Espressif’s dual-core processor with integrated WiFi and Bluetooth. Few of us though will have explored all of its features, including its built-in encryption facilities and secure booting capability. With these, a developer can protect and secure their code, and keep their devices secure.

That sense of security may now be illusory though, thanks to [LimitedResults] who has developed a series of attacks on the chip that compromise its crypto core, secure boot, and flash encryption. This enables both the chance of arbitrary code execution and firmware extraction on locked-down ESP32 devices.

To achieve all this he used a glitching technique on the device’s power supply, inserting a carefully timed glitch in the rail to coincide with a particular instruction being executed. For those of us who are not experts in this technique, he provides a basic primer with a description of his home-made glitcher made using a CMOS switch chip.

It appears that there is no solution to this attack short of new silicon, however, it should be borne in mind that it’s something that depends upon a specialist hacker with a well-equipped bench, and is thus only likely to be a significant headache to manufacturers. But it undermines a key feature of a major line of microcontrollers, and as such it remains a significant piece of work.