We’re all used to the humble LED as a ubiquitous source of light, but how many of us are aware that these components can also be used as photodiodes? It’s something [Giovanni Blu Mitolo] takes us through as he demonstrates a simple data link using just a pair of LEDs and a couple of Arduinos. It’s a showing off his PJON networking layer, and while you’d need a bit more than a couple of LEDs on breadboards for a real-world application, we still think it’s a neat demonstration.
PJON itself is very much worth a look, being an implementation of a robust and error-tolerant network for Arduinos and other small microcontroller platforms. It has a variety of communication strategies for various different media, and as this LED demonstration shows, its strength is that it’s capable of working through media that other networks would balk at. Whether it’s controlling home automation through metal heating ducts or providing an alternative to LoRa at 433 MHz, it’s definitely worth a second look. We’ve mentioned it before, but remain surprised that we haven’t seen it more often since. Take a look, the video is below the break.
Messing about in boats has always held a curious appeal for the hardware hacker. Perhaps that’s because it remains an approachable way to make something that moves under its own power with a bit of speed, and barring calamities, the worst that can happen to the unwary boater is a soaking. [NASAT Channel] is a Vietnamese hacker who is a serial producer of small motorised boats, and one of his latest is a particularly impressive example.
The boat itself is a relatively conventional expanded polystyrene hull covered with fiberglass, but the motive power is something a little special. He’s taken eight of the ubiquitous 775 DC brushed motors and used them in a star configuration with beveled gears, which in turn drives a flexible shaft which goes straight to a propeller under the craft. Each motor shares a water cooling pipe serviced by a small pump, and the drive comes from a pair of cheap PWM motor controllers. We see him zipping up and down a stretch of river next to some moored boats, and if we’re honest, we wouldn’t mind a go ourselves.
We’re not entirely convinced such a rough-and-ready eight-way gearbox will be reliable for long-term use, and we’d be interested to know just how equally so many motors are actually sharing the load. But we like it for its sheer audacity, and we think you will too. Take a look at the video below the break, and if you’re inspired then grab a hammock, some friends, and have a go.
For a while now a series of stories have been circulating about Amazon’s Ring doorbell, an Internet-connected camera and entry system that lets users monitor and even interact with visitors and delivery people at their doors. The adverts feature improbable encounters with would-be crooks foiled by the IoT-equipped homeowner, but the stories reveal a much darker side. From reports of unhindered access by law enforcement to privately-held devices through mass releases of compromised Ring account details to attackers gaining access to children via compromised cameras, it’s fair to say that there’s much to be concerned about.
One cause for concern has been the location data exposed by the associated Amazon Neighbors crowd-sourced local crime paranoia app, and for those of us who don’t live and breathe information security there is an easy-to-understand Twitter breakdown of its vulnerabilities from [Elliot Alderson] that starts with the app itself and proceeds from there into compromising Ring accounts by finding their passwords. We find that supposedly anonymized information in the app sits atop an API response with full details, that there’s no defense against brute-forcing a Ring password, and that a tasty list of API and staging URLs is there for all to see embedded within the app. Given all that information, there’s little wonder that the system has proven to be so vulnerable.
As traditional appliance makers have struggled with bringing Internet connectivity into their products there have been a few stories of woeful security baked into millions of homes. A defense could be made that a company with roots outside the Internet can be forgiven for such a gaffe, but in the case of Amazon whose history has followed that of mass Web adoption and whose infrastructure lies behind so much of the services we trust, this level of lax security is unforgivable. Hackaday readers will be aware of the security issues behind so-called “smart” devices, but to the vast majority of customers they are simply technological wonders that are finally delivering a Jetsons-style future. If some good comes of these Ring stories it might be that those consumers finally begin to wake up to IoT security, and use their new-found knowledge to demand better.
Though many of us will never have experimented with it, most readers should be familiar with DTMF as the tones used by the telephone system for dialling. If your youth was not misspent mashing 4-4-2-6-4-6-2, 4-4-2-6-4-1 into a keypad, then you haven’t lived!
As you might expect there are a variety of chipsets to handle DTMF, and one of them has been used by [ackerman] in a slightly unusual way. Many desktop computers do not have a convenient array of GPIOs upon which to hang a piece of hardware, but a constant among them is to support some form of gaming controller. Hence he’s taken a commodity joypad and interfaced a MT8870 DTMF decoder to its switch lines with a simple transistor buffer, and is able to pull the resulting information out in the host operating system. So far there are versions for Windows, DOS, Amstrad CPC, Arduino, and even PSX ( the original PlayStation console ).
One might ask why on earth you might want a DTMF input for your desktop PC, but to do so is to miss the point. We are surrounded by computing devices from our mobile phones upwards that do not have any form of interface that can easily be used by our electronic projects, and this serves as an example of how with a bit of ingenuity that can be overcome. It’s a subject we’ve touched upon before, when we asked why people aren’t hacking their cellphones.
The SDR revolution has brought a bonanza of opportunities for experimentation to the radio enthusiast, but with it has come a sometimes-confusing array of software for which even installation can be a difficult prospect for an SDR novice. If you’re bamboozled by it all then help may be at hand courtesy of [Luigi Cruz], who has packaged a suite of ready-to-go popular SDR software in an OS image for the Raspberry Pi.
On board the Raspbian-based OS image are SDR Angel, Soapy Remote, GQRX, GNURadio, LimeUtil, and LimeVNA. In hardware terms the RTL-SDR is supported, along with the LimeSDR, PlutoSDR, Airspy, and Airspy HF. All are completely ready-to-go and even have desktop shortcuts, so if the CLI scares you then you can still dive in and play. More importantly it’s designed for use with SDR transmitters as well as receivers, so the barrier for full SDR operation for radio amateurs has become significantly lower too.
This year has seen the seven-year anniversary of the RTL-SDR hack that probably did most to kickstart the use of SDRs in our community. Our colleague [Tom Nardi] wrote a retrospective that’s worth a look for its overview of some SDR tricks that have evolved over that time. Meanwhile if you don’t mind restricting your outlook somewhat, it’s possible to turn the Raspberry Pi 3 into an SDR all without any extra hardware.
By now we are all used to the role of the printed circuit board in artwork, because of the burgeoning creativity in the conference and unofficial #BadgeLife electronic badge scenes. When the masters of electronic design tools turn their hand to producing for aesthetic rather than technical reasons, the results were always going to be something rather special.
Nick Poole is an ace wrangler of electrons working for SparkFun, and as such is someone with an impressive pedigree when it comes to PCB design. Coming on stage sporting a beret with an awesome cap badge, his talk at the recent Hackaday Superconference concerned his experience in pushing the boundaries of what is possible in PCB manufacture. It was a primer in the techniques required to create special work in the medium of printed circuit boards, and it should be essential viewing for anybody with an interest in this field.
Though he starts with the basics of importing graphics into a PCB design package, the meat of his talk lies in going beyond the mere two dimensions of a single PCB into the third dimension either by creating PCBs that interlock, or by stacking boards.
Last month we carried a piece looking at the development of the 8-bit home computer market through the lens of the British catalogue retailer Argos and their perennial catalogue of dreams. As an aside, we mentioned that the earliest edition from 1975 contained some of the last mechanical calculators on the market, alongside a few early electronic models. This month it’s worth returning to those devices, because though they are largely forgotten now, they were part of the scenery and clutter of a typical office for most of the century.
The Summa’s internals, showing the register on the right and the type wheels on the left.
Somewhere in storage I have one of the models featured in the catalogue, an Olivetti Summa Prima. I happened upon it in a dumpster as a teenager looking for broken TVs to scavenge for parts, cut down a pair of typewriter ribbon reels to fit it, and after playing with it for a while added it to my store of random tech ephemera. It’s a compact and stylish desktop unit from about 1970, on its front is a numerical keypad, top is a printer with a holder for a roll of receipt paper and a typewriter-style rubber roller, while on its side is a spring-loaded handle from which it derives its power. It can do simple addition and subtraction in the old British currency units, and operating it is a simple case of punching in a number, pulling the handle, and watching the result spool out on the paper tape. Its register appears to be a set of rotors advanced or retarded by the handle for either addition or subtraction, and its printing is achieved by a set of print bars sliding up to line the correct number with the inked ribbon. For me in 1987 with my LCD Casio Scientific it was an entertaining mechanical curiosity, but for its operators twenty years earlier it must have represented a significant time saving.
The history of mechanical calculators goes back over several hundred years to Blaise Pascal in the 17th century, and over that time they evolved through a series of inventions into surprisingly sophisticated machines that were capable of handling financial complications surprisingly quickly. The Summa was one of the last machines available in great numbers, and even as it was brought to market in the 1960s its manufacturer was also producing one of the first desktop-sized computers. Its price in that 1975 Argos catalogue is hardly cheap but around the same as an electronic equivalent, itself a minor miracle given how many parts it contains and how complex it must have been to manufacture.
We’ve put two Summa Prima videos below the break. T.the first is a contemporary advert for the machine, and the second is a modern introduction to the machine partially narrated by a Brazilian robot, so consider translated subtitles. In that second video you can see something of its internals as the bare mechanism is cranked over for the camera and some of the mechanical complexity of the device becomes very obvious. It might seem odd to pull a obsolete piece of office machinery from a dumpster and hang onto it for three decades, but I’m very glad indeed that a 1980s teenage me did so. You’re probably unlikely to stumble upon one in 2019, but should you do so it’s a device that’s very much worth adding to your collection.
