Author: Jenny List

OpenAg Is A Personal Food Computer

December 26, 2016 by 4 Comments

When a device that calls itself a personal food computer lands in your timeline, what image springs to mind? A cloud-connected diet aid perhaps, advertised on TV infomercials by improbably fit-looking Californian ladies crediting all their health to a palm-sized unit that can be yours for only 199 dollars. Fortunately that proved not to be the case, and on further reading our timeline story was revealed to be about a computerized farming device.

The OpenAg Food Computer  from the MIT Media Lab Open Agriculture Initiative bills itself as:

“a controlled-environment agriculture technology platform that uses robotic systems to control and monitor climate, energy, and plant growth inside of a specialized growing chamber”

It takes the form of a tabletop enclosure in which so-called climate recipes to replicate different conditions for plant growth can be tested. It’s probably fair to say that in this most basic form it is more of an educational device than one for full-scale food production, though they are applying the same technologies at a much greater scale. Their so-called “Food servers” are banks of OpenAg environments in freight containers, which definitely could be used to provide viable quantities of produce.

The good news is that the project is open source, and their latest story is that they have released version 2.0(alpha) of the device. If you are interested, you can read the documentation, and find all the resources you need to build one on their GitHub repository. They page linked above has a video that’s very much of the slick PR variety rather than the nuts-and-bolts, so we’ve sought out their build video for you below the break instead. Continue reading “OpenAg Is A Personal Food Computer” →

Automated Vacuum Lettuce Seed Placement

December 26, 2016 by 4 Comments

[Jethro Tull] is a name you may well associate with a 1970s prog/folk rock band featuring a flautist, but the original [Tull] was an inventor whose work you benefit from every day. He was a British lawyer and landowner who lived over the turn of the 18th century, and who invented among other things the mechanical seed drill.

Were [Tull] alive today he would no doubt be impressed by the work of [Akash Heimlich], who has created an exquisite vacuum seed placer for his rooftop hydroponic lettuce farm. Unlike the continuous rows of seed on the Berkshire earth of [Tull]’s farm, the lettuce seed must be placed in an even grid on a foam substrate for the hydroponic equivalent. This was an extremely tedious task when done by hand, so [Akash] set about automating the process with a vacuum seeder that is a thing of beauty.

It uses a simple yet effective mechanism involving a row of pipettes connected to a vacuum line, that are rotated over a vibrating hopper of seeds from which each one collects a single seed, before being rotated back over the foam where the seeds are dropped in a neat row through 3D-printed funnels. The foam is advanced, and the process is repeated until there is a neat grid of seeds. In only four minutes it can deliver 150 seeds, reducing several hours work into under half an hour.

The whole machine is controlled by an Arduino, with a couple of stepper motors to move foam and pipettes alongside the vibrator motor. You can see its operation in the video below the break.

Continue reading “Automated Vacuum Lettuce Seed Placement” →

Hackspace U

December 26, 2016 by 40 Comments
No Timmy, we're not preparing you for a life of mindless drudgery! PD, via Wikimedia Commons.
No Timmy, we’re not preparing you for a life of mindless drudgery! PD, via Wikimedia Commons.

It’s funny, how obsessed we are with qualifications these days. Kids go to school and are immediately thrust into a relentless machine of tests, league tables, and exams. They are ruthlessly judged on grades, yet both the knowledge and qualifications those grades represent so often boil down to relatively useless pieces of paper. It doesn’t even end for the poor youngsters when they leave school, for we are now in an age in which when on moving on from school a greater number of them than ever before are expected to go to university. They emerge three years later carrying a student debt and a freshly-printed degree certificate, only to find that all this education hasn’t really taught them the stuff they really need to do whatever job they land.

A gold standard of education is revealed as an expensive piece of paper with a networking opportunity if you are lucky. You need it to get the job, but in most cases the job overestimates the requirement for it. When a prospective employer ignores twenty years of industry experience to ask you what class of degree you got twenty years ago you begin to see the farcical nature of the situation.

In our hackspaces, we see plenty of people engaged in this educational treadmill. From high schoolers desperately seeking to learn something other than simply how to regurgitate the textbook, through university students seeking an environment closer to an industrial lab or workshop, to perhaps most interestingly those young people who have eschewed university and gone straight from school into their own startups.

Continue reading “Hackspace U” →

The First Bug On Mars

December 25, 2016 by 13 Comments

Interplanetary probes were a constant in the tech news bulletins of the 1960s and 1970s. The Space Race was at its height, and alongside their manned flights the two superpowers sent unmanned missions throughout the Solar System. By the 1980s and early 1990s the Space Race had cooled down, the bean counters moved in, and aside from the spectacular images of the planets periodically arriving from the Voyager series of craft there were scant pickings for the deep space enthusiast.

The launch in late 1996 of the Mars Pathfinder mission with its Sojourner rover then was exciting news indeed. Before Spirit, the exceptionally long-lived Opportunity, and the relatively huge Curiosity rover (get a sense of scale from our recent tour of JPL), the little Sojourner operated on the surface of the planet for 85 days, and proved the technology for the rovers that followed.

In these days of constant online information we’d see every nuance of the operation as it happened, but those of us watching with interest in 1997 missed one of the mission’s dramas. Pathfinder’s lander suffered what is being written up today as the first bug on Mars. When the lander collected Martian weather data, its computer would crash.

Like many other spacecraft, the lander’s computer system ran the real-time OS VxWorks. Of the threads running on the craft, the weather thread was a low priority, while the more important task of servicing its information bus was a high priority one. The weather task would hog the resources, causing the operating system equivalent of an unholy row in our Martian outpost. A priority inversion bug, and one that had been spotted before launch but assigned a low priority.

You can’t walk up to a computer on another planet and swap out a few disks, so the Pathfinder team had to investigate the problem on their Earthbound replica of the lander. The fix involved executing some C code on an interpreter prompt on the spacecraft itself, something that would give most engineers an extremely anxious moment.

The write-up is an interesting read, it’s a translation from a Russian original that is linked within it. If the work of the JPL scientists and engineers interests you, this talk from the recent Hackaday superconference might be of interest.

[via Hacker News]

Track Wi-Fi Devices In Your Home

December 25, 2016 by 29 Comments

How do you audit your home Wi-Fi network? Perhaps you log into your router and have a look at the connected devices. Sometimes you’ll find an unexpected guest, but a bit of detective work will usually lead you to the younger nephew’s game console or that forgotten ESP8266 on your bench.

Wouldn’t it be useful if your router could tell you where all the devices connected to it are? If you are [Zack Scholl], you can do all this and more, for his FIND-LF system logs Wi-Fi probe requests from all Wi-Fi devices within its range even if they are not connected, and triangulates their position from their relative signal strengths across several sniffing receivers. These receivers are a network of Raspberry Pis with their own FIND-LF server, and any probe requests they pick up are forwarded to [Zack]’s FIND server (another of his projects) which does the work of collating the locations of devices.

It’s an impressive piece of work, though with a Raspberry Pi at each receiver it could get a little pricey. [Zack] has done other work in this field aside from the two projects mentioned here, his other work includes an implementation of the [Harry Potter] Marauder’s Map.

This is by no means the only indoor location system we’ve seen over the years. One that uses ESP8266 modules for example, or this commercial product that is similar to the project shown here.

Power For An Amstrad Spectrum

December 23, 2016 by 31 Comments

If you were an American child of the early 1980s then perhaps you were the owner of a Commodore 64, an Apple II, or maybe a TRS-80. On the other side of the Atlantic in the UK the American machines were on the market, but they mostly lost out in the hearts and minds of eager youngsters to a home-grown crop of 8-bit micros. Computer-obsessed British kids really wanted Acorn’s BBC Micro, but their parents were more likely to buy them the much cheaper Sinclair ZX Spectrum.

Sinclair Research was fronted by the serial electronic entrepreneur [Clive Sinclair], whose love of miniaturization and ingenious cost-cutting design sometimes stretched the abilities of his products to the limit. As the 8-bit boom faded later in the decade the company faltered, its computer range being snapped up by his great rival in British consumer electronics, [Alan Sugar]’s Amstrad.

The Amstrad Spectrums replaced the rubber and then shaky plastic keys of the Sinclair-era machines with something considerably more decent, added joystick ports and a choice of a built-in cassette deck or one of those odd 3″ floppy disk drives for which Amstrad seemed to be to only significant customer. For that they needed a more capable power supply offering a selection of rails, and it is this unit that concerns us today. [Drygol] had a friend with an Amstrad-made Sinclair 128K Spectrum +2 with a broken power supply. His solution was to wire in a supply retrieved from a small form factor PC that had all the requisite lines, and for safety he encased it in an improbably huge piece of heat shrink tubing.

Wiring a PSU to a DIN plug for a retro computer is not an exceptional piece of work in itself even if it’s tidily done and nice to see older hardware brought back to life. What makes this piece worth a look instead is the teardown of what is a slightly unusual footnote to the 8-bit home computer story. We’re shown the familiar Z80 and support chips with the Spectrum edge connector and modulator on a through-hole board with a piece of cutting edge tech for a 1980s home computer, a single SMD chip unusually mounted nestled in a hole cut in the board.

Amstrad eventually stopped making Spectrums in the early 1990s, having also tried the Sinclair name on a spectacularly awful PC-compatible home computer. [Clive Sinclair] continued to release electronic products over the following decades, including a portable computer, the last of his trademark miniature radio receivers, and an electric bicycle accessory. Amstrad continue to make computers to this day, and [Alan Sugar] has achieved fame of a different sort as host of the UK version of The Apprentice. He has not yet become Prime Minister.

We’ve featured another Amstrad Spectrum +2 losing its tape deck for a slimmer machine. On that note, the Spectrum wasn’t Amstrad’s only entry in the 8-bit market, and we’ve also shown you a compact clone of their CPC464. As for [Drygol], he’s featured here several times. His mass-restoration of Commodore 64s for instance, or bringing a broken Atari ST back from the dead.

Get On 10 GHz For 3 Euros

December 22, 2016 by 15 Comments

A frequent complaint you will hear about amateur radio is that it is a chequebook pursuit. Of course you can work the incredible DX if you spend $20k on a high-end radio, big antenna, and associated components. The reality is though that because it’s such a multi-faceted world there are many ways into it of which the operator with the shiny rig is taking only one.

On the commonly used HF and VHF bands at the lower end of the radio spectrum you will definitely find chequebook amateurs of the type described in the previous paragraph. But as you ascend into the microwave bands there are no shiny new radios on the market, so even the well-heeled licensee must plow their own furrow and build their own station.

You might think that this would remain a chequebook operation of a different type, as exotic microwave devices are not always cheap. But in fact these bands have a long history of extremely inexpensive construction, in which skilled design and construction as well as clever re-use of components from satellite TV systems and Doppler radar modules play a part. And it is a project following this path that is our subject today, for [Peter Knol, PA1SDB] has repurposed a modern Doppler radar module as a transmitter for the 10GHz or 3cm amateur band (Google Translate version of Dutch original). The best bit about [Peter]’s project is the price: these modules can be had for only three Euros.

Years ago a Doppler module would have used a Gunn diode in a waveguide cavity and small horn, usually with an adjacent mixer diode for receiving. Its modern equivalent uses a transistor oscillator on a PCB, with a dielectric resonator and a set of patch antennas. There is also a simple receiver on board, but since [Peter] is using a converted ten-Euro satellite LNB for that task, it is redundant.

He takes us through the process of adjusting the module’s frequency before showing us how to mount it at the prime focus of a parabolic antenna. FM modulation comes via a very old-fashioned transformer in the power feed. He then looks at fitting an SMA connector and using it for more advanced antenna set-ups, before experimenting with the attenuating properties of different substances. All in all this is a fascinating read if you are interested in simple microwave construction.

The result is not the most accomplished 10 GHz station in the world, but it performs adequately for its extremely low price given that he’s logged a 32 km contact with it.

Though we cover our fair share of amateur radio stories here at Hackaday it’s fair to say we haven’t seen many in the microwave bands. If however you think we’ve been remiss in this area, may we point you to our recent coverage of a microwave radio receiver made from diamond?

Via Southgate ARC.