HFSat And The All-HF Amateur Radio Satellite Transponder

November 3, 2016 by Jenny List 17 Comments

One facet of the diverse pursuit that is amateur radio involves the use of amateur radio satellites. These have a long history stretching back to the years shortly after the first space launches, and have been launched as “piggy-back” craft using spare capacity on government and commercial launches.

Though a diverse range of payloads have been carried by these satellites over the years, the majority of amateur radio satellites have featured transponders working in the VHF and UHF spectrum. Most often their links have used the 2m (144 MHz) and 70cm (430MHz) bands. A few have had downlinks in the 10m (28MHz) band, but this has been as far as they have ventured into the HF spectrum.

A new cubesat designed and built by trainees at the US Naval Academy promises to change all that, because it will feature an all-HF transponder with a 15m (21MHz) uplink and a 10m downlink. To that end it will carry a full size 10m wire dipole antenna. The 30KHz wide transponder is an inverting design intended to cancel out the effects of Doppler shift. In their write-up they provide a fascinating description of many aspects of cubesat design, one which should be of significant interest beyond the world of amateur radio.

If the subject of amateur radio in space interests you, have a look at our series on the matter, first covering the OSCAR satellites, and then our recent feature on its use in manned missions.

[via Southgate ARC]

Computer Emulation In The Manner Of A Turducken

November 2, 2016 by Jenny List 39 Comments

If you come from somewhere with a tradition of eating a meal of roast turkey or goose to celebrate Christmas, Thanksgiving, or other holidays, then maybe you’ve encountered the three-bird roast, or Turducken. A deboned duck is stuffed with a deboned chicken, and in turn the combination is stuffed into a turkey All the gaps are filled with sausage meat stuffing, and the resulting combination is roasted for a serious meat-fest. Vegetarians, please look away.

It’s something of an excess of poultry, but the three-bird roast is a delicacy that definitely works. We’re not so sure about the link that prompted this journey into celebration poultry dishes by reminding us of a turducken, but we’ll leave the verdict to you the reader. Someone has created an unholy turducken-style chain of emulators that delivers a Sinclair ZX Spectrum on a Linux machine via Windows, DOS, and the Commodore 64. If it had its own word like the poultry dish it might be a Linwindoscomtrum, but let’s not go there.

The linwincomtrum in all its glory. — The linwindoscomtrum in all its glory.

So how have they done it? First, they took Lubuntu, and installed WINE. (OK, Wine Is Not an Emulator, we know that, but go with the story for a moment) Then they installed DOSBox under WINE for a DOS command prompt, and ran no$C64, a Commodore 64 emulator. On that they ran the c642spec Sinclair ZX Spectrum emulator, and finally arrived in a ZX BASIC prompt.

The author does make the point at the start of the write-up that it’s a waste of ten minutes, but even though the result is an overly complex way to slowly emulate an archaic home computer on a modern one we’ll still give them ten out of ten for the effort.

Incidentally, the author does not identify themself and there is little clue in the form of the rest of the site to identify them, so unusually for a Hackaday piece we can not give credit where it is due. We do however salute the anonymous emulator pilot for their glorious folly.

If the ZX piques your interest, we’ve featured a coding tutorial for the rubber-keyed British micro in the past, as well as a later one having a tape-drive-ectomy, and of course the hellzxschreiber amateur radio Hellschreiber receiver.

Via Hacker News. ZX Spectrum image: Bill Bertram [CC BY-SA 2.5], via Wikimedia Commons.

Stealth Cell Tower Inside This Office Printer Calls To Say I Love You

November 2, 2016 by Jenny List 35 Comments

If you look around the street furniture of your city, you may notice some ingenious attempts to disguise cell towers. There are fake trees, lamp posts with bulges, and plenty you won’t even be aware of concealed within commercial signage. The same people who are often the first to complain when they have no signal it seems do not want to be reminded how that signal reaches them. On a more sinister note, government agencies have been known to make use of fake cell towers of a different kind, those which impersonate legitimate towers in order to track and intercept communications.

In investigating the phenomenon of fake cells, [Julian Oliver] has brought together both strands by creating a fake cell tower hidden within an innocuous office printer. It catches the phones it finds within its range, and sends them a series of text messages that appear to be from someone the phone’s owner might know. It then prints out a transcript of the resulting text conversation along with all the identifying information it can harvest from the phone. As a prank it also periodically calls phones connected to it and plays them the Stevie Wonder classic I Just Called To Say I Love You.

In hardware terms the printer has been fitted with a Raspberry Pi 3, a BladeRF software-defined transceiver, and a pair of omnidirectional antennas which are concealed behind the toner cartridge hatch. Software comes via YateBTS, and [Julian] provides a significant amount of information about its configuration as well as a set of compiled binaries.

In one sense this project is a fun prank, yet on the other hand it demonstrates how accessible the technology now is to impersonate a cell tower and hijack passing phones. We’re afraid to speculate though as to the length of custodial sentence you might receive were you to be caught using one as a private individual.

We’ve considered the Stingray cell phone trackers before here at Hackaday, as well as looking at a couple of possible counter-measures. An app that uses a database of known towers to spot fakes, as well as a solution that relies on an SDR receiver to gather cell tower data from a neighbourhood.

[via Hacker News]

Sort Your Candy With A Raspberry Pi And Google Cloud Vision

October 31, 2016 by Jenny List 15 Comments

If you have been off trick-or-treating and returned home with an embarassment of candy, what on earth can you do to mange the problem and sort it by brand?

Yes, it’s an issue that so many of us have had to face at this time of year. So much a challenge, that the folks at [Dexter Industries] have made a robotic candy-sorter to automate the task.

OK, there’s something of the tongue-in-cheek about the application. But the technology they’ve used is interesting, and worth a second look. Hardware wise it’s a Lego Mindstorms conveyor and hopper controlled by a Raspberry Pi through the BrickPi interface. All very well, but it’s in the software that the interest lies. They use the Raspberry Pi’s camera to take a picture to send off to Google Cloud Vision, which they then query to return a guess at the brand of the candy in question. The value returned is then compared to a list of brands to keep or donate to another family member, and the hopper tips the bar into the respective pile. They provide full build details and code, as well as the video we’ve put below the break. So simple a child can explain it, sort of.

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The Lotus Sevens: The Real Most-Hackable Cars

October 31, 2016 by Jenny List 64 Comments

In the late 1940s and early 1950s, Europe was still struggling to recover from the crippling after-effects of war. In Britain it is referred to as the “austerity period”, with food still rationed and in which “make do and mend” was very much the order of the day. The consumer boom of the late 1950s and 1960s was very far in the future, and if you were a hardware hacker your source materials were limited to whatever you could find from war surplus or whatever prewar junk might come your way. This was a time in which the majority of adults had recently returned from war service, during which they had acquired practical skills through the necessities of battle that they sought an outlet for in peacetime.

One field that benefited from this unexpected flowering of creativity was that of motor racing. Before the war it had been an exclusive pursuit, with bespoke cars at famous circuits like the banked track at Brooklands, in Surrey. In a reflection of the wider social changes that followed the war the motor racers of the post-war years came from humbler backgrounds, they raced homemade specials made from tired-out prewar motors on wartime airfield perimeter tracks like the one at Silverstone which still hosts Formula One racing today.

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Robotic Farming, Aussie Style

October 30, 2016 by Jenny List 41 Comments

Australian roboticists from the Queensland University of Technology have developed a prototype agricultural robot that uses machine vision to identify both weed and crop plants before either uprooting or poisoning the weeds or applying fertiliser to the crop.

The machine is a wide platform designed to straddle a strip of the field upon which it is working, with electric wheel motors for propulsion. It is solar-powered, and it is envisaged that a farm could have several of them continuously at work.

At a superficial level there is nothing new in the robot, its propulsion, or even the plant husbandry and weeding equipment. The really clever technology lies in the identification and classification of the plants it will encounter. It is on the success or failure of this in real farm environments that the robot’s future will hinge. The university’s next step will be to take it on-farm, and the ABC report linked above has a wonderfully pithy quote from a farmer on the subject. You can see the machine in action in the video below the break.

Farming robots have a significant following among the hardware hacker community, but it is possible that the machine-vision and plant-identifying abilities of this one would be beyond most hackers. However it is still an interesting project to watch, marking as it does a determined attempt to take the robot out of the lab and into real farm settings.

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Not Quite 101 Uses For An ATX Power Supply

October 28, 2016 by Jenny List 82 Comments

The PC power supply has been a standard of the junk box for the last couple of decades, and will probably continue to be for the foreseeable future. A product that is often built to a very high standard and which will give years of faithful service, yet which has a life of only a few years as the PC of which it is a part becomes obsolete. Over the decades it has evolved from the original PC and AT into ATX, supplying an ever-expanding range of voltage rails at increasing power levels. There have been multiple different revisions of the ATX power supply standard over the years, but they all share the same basic form factor.

So a pile of ATX supplies will probably feature in the lives of quite a few readers. Most of them will probably be old and obsolete versions of little use with today’s motherboards, so there they sit. Not small enough to ignore, yet Too Good To Throw Away. We’re going to take a look at them, try to work out what useful parts they contain, and see a few projects using them. Maybe this will provide some inspiration if you’re one of those readers with a pile of them seeking a purpose.

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