Most parts of the radio spectrum are shared between more than one user, and there is usually a primary occupant and a secondary one whose usage is dependent upon not interfering with other users. If you’ve used 435 MHz radio modems you will have encountered this, that’s a band shared with both radio amateurs and others including government users. While some countries have wider band limits, the two-meter band between 144 MHz and 146 MHz is allocated with primary status to radio amateurs worldwide, and it is this status that is placed under threat. The latest ARRL news is that there has been little opposition at the pan-European regulator CEPT level, which appears to be causing concern among the amateur radio community.
Why should this bother you? If you are a radio amateur it should be a grave concern that a band which has provided the “glue” for so many vital services over many decades might come under threat, and if you are not a radio amateur it should concern you that a commercial defence contractor in one country can so easily set in motion the degradation of a globally open resource governed by international treaties penned in your grandparents’ time. Amateur radio is a different regulatory being from the licence-free spectrum that we now depend upon for so many things, but the principle of it being a free resource to all its users remains the same. If you have an interest in retaining the spectrum you use wherever on the dial it may lie, we suggest you support your national amateur radio organisation in opposing this measure.
Anyone with a cat knows that the little purring ball of fluff in your lap is one tiny step away from turning into a bloodthirsty serial killer. Give kitty half a chance and something small and defenseless is going to meet a slow, painful end. And your little killer is as likely as not to show off its handiwork by bringing home its victim – “Look what I did for you, human! Are you not proud?”
As useful as a murder-cat can be, dragging the bodies home for you to deal with can be – inconvenient. To thwart his adorable serial killer [Metric], Amazon engineer [Ben Hamm] turned to an AI system to lock his prey-laden cat out of the house. [Metric] comes and goes as he pleases through a cat flap, which thanks to a solenoid and an Arduino is now lockable. The decision to block entrance to [Metric] is based on an Amazon AWS DeepLens AI camera, which watches the approach to the cat flap. [Ben] trained three models: one to determine if [Metric] was in the scene, one to determine whether he’s coming or going, and one to see if he’s alone or accompanied by a lifeless friend, in which case he’s locked out for 15 minutes and an automatic donation is made to the Audubon Society – that last bit is pure genius. The video below is a brief but hilarious summary of the project for an audience in Seattle that really seems quite amused by the whole thing.
So your cat isn’t quite the murder fiend that [Metric] is? An RFID-based cat door might suit your needs better.
Greenhouses are a great way to improve conditions for your plants, and are an absolute necessity for any serious gardening in colder climates. When the time came for [gentleworks] to build a new greenhouse, rather than going with a conventional design, they decided to go with a geodesic dome instead.
The greenhouse uses a few techniques that will be unfamiliar to those used to run-of-the-mill carpentry. The individual cedar struts meet at a series of hubs, constructed out of short lengths of Schedule 80 PVC pipe. The struts are attached to the pipe with steel straps, screwed into place. This doesn’t give the strongest of holds, but as most of the loads on the struts are compressive in nature, it works well in practice. Plastic sheeting is used as a covering to help let in plenty of light while keeping the cold out. The greenhouse is also heated, and can maintain a 40 deg F temperature differential with 14,000 BTUs.
It doesn’t seem as though bending wire would be much of a chore, but when you’re making art from your circuits, it can be everything. Just the right angle in just the right place can make the difference between a circuit sculpture that draws gasps and one that’s only “Meh.”
[Jiří Praus] creates circuit sculptures that are about as far away from the “Meh” end of the spectrum as possible. And to help him make them even more spectacular, he has started prototyping a wire-bending machine to add precision to his bends. There’s no build log at the moment, but the video below shows progress to date. All the parts are 3D-printed, with two NEMA 17 steppers taking care of both wire feed and moving the bending head. It appears that the head has multiple slots for tools of different shapes. For now, the wire is rotated around its long axis manually, but another stepper could be added to take care of that job.
[Jiří] tells us that while he loves making circuit sculptures like his amazing mechanical tulip, he hates repeating himself. He hopes this bender will make repeat jobs a little less tedious and a lot more precise, and we hope he goes forward with the build so we get to see both it and more of his wonderful works of circuit art.
Across the Northern Hemisphere it is now summer and the growing season is in full swing. Vigorous plants that will soon bear tasty fruit are springing forth from the soil, but unfortunately so are a lush carpet of weeds that require the constant attention of the gardener. “If only there were a machine that could take that on!” she cries, and as it happens she’s in luck.
The FarmBot is an open-source robotic vegetable grower able to take care of all aspects of sowing and tending a vegetable plot. We first saw them five years as a semifinalist in the first Hackaday Prize. This is a CNC machine for the raised beds of your backyard garden. Give it power, water, and a WiFi connection, and FarmBot goes into service planting, watering, weeding, and monitoring the soil. Now they’ve shipped over a thousand of their Genesis model and today have announced of a pair of new models that promise to make their technology more accessible than it ever has been.
In a nod to Tesla, FarmBot is calling this their “Model 3 moment” — the new offering is smaller and leaner to appeal to a wider customer base than their well-heeled, CNC machine loving, early adopters. The new FarmBot Express and Express XL models are now shipped 95% pre-assembled to lower the bar on getting up and running. They cover two sizes of planting bed: 1.2m x 3m or 2.4m x 6m, with an MSRP of $2295/2795 although there is currently an $800 launch discount available.
For us, FarmBot is the success story of an early Hackaday Prize entrant. From a great idea and a functional prototype, the project has successfully made the transition to commercial viability and holds a genuine promise of making the world a better place by helping people grow some of their own produce. Who knows, in five years time it could be your idea that’s reaching commercial viability, we think you should enter the Hackaday Prize too!
There’s been a lot of news lately about the Long Now Foundation and Jeff Bezos spending $42 million or so on a giant mechanical clock that is supposed to run for 10,000 years. We aren’t sure we really agree that it is truly a 10,000 year clock because it draws energy — in part — from people visiting it. As far as we can tell, inventor Danny Hills has made the clock to hoard energy from several sources and occasionally chime when it has enough energy, so we aren’t sure how it truly sustains itself. However, it did lead us to an interesting question: how could you design something that really worked for 10,000 years?
It’s hard not to be impressed by the Arduboy. In just a few short years, [Kevin Bates] went from proof of concept to a successful commercial product without compromising on his original open source goals. Today, anyone can develop a game for the Arduboy and have it distributed to owners all over the world for free. If you’ve ever dreamt of being a game developer, the Arduboy community is for you.
Realizing the low-cost hardware and open source software of the Arduboy makes it an excellent way to learn programming, [Kevin] is now trying to turn his creation into a legitimate teaching tool. He’s kicking off this new chapter in the Arduboy’s life with a generous offer: giving out free hardware to educators all over the world. Anyone who wants to be considered for the program just needs to write-up a few paragraphs on how they’d utilize the handheld game system in their class.
[Kevin] already knows the Arduboy has been used to teach programming, but those have all been one-off endeavours. They relied on a teacher that was passionate enough about the Arduboy to put in their own time and effort to create a lesson plan around it. So one of the main goals right now is getting an official curriculum put together so educators won’t have to start from scratch. The community has already developed 16 free lessons, but they’re looking for help in creating more and translating them into other languages.
While the details are still up in the air, [Kevin] also plans to travel to schools personally and help them get their Arduboy classes off the ground. He’s especially interested in developing countries and other areas that are disadvantaged educationally. Believing that the Arduboy is as much a way to teach effective leadership and teambuilding as it is programming, he thinks this program can truly make a difference.