Raspberry Pi Tracks Humans, Blasts Them With Heat Rays

Given how long humans have been warming themselves up, you’d think we would have worked out all the kinks by now. But even with central heating, and indeed sometimes because of it, some places we frequent just aren’t that cozy. In such cases, it often pays to heat the person, not the room, but that can be awkward, to say the least.

Hacking polymath [Matthias Wandel] worked out a solution to his cold shop with this target-tracking infrared heater. The heater is one of those radiant deals with the parabolic dish, and as anyone who’s walked past one on demo in Costco knows, they throw a lot of heat in a very narrow beam. [Matthias] leveraged a previous project that he whipped up for offline surveillance as the core of the project. Running on a Raspberry Pi with a camera, the custom software analyzes images and locates motion across the width of a frame. That drives a stepper that swivels a platform for the heater. The video below shows the build and the successful tests; however, fans of [Matthias] should prepare themselves for a shock as he very nearly purchases a lazy susan to serve as the base for the heater rather than building one.

We’re never disappointed by [Matthias]’ videos, and we’re always impressed by his range as a hacker. From DIY power tools to wooden logic circuits to his recent Lego chocolate engraver, he always finds ways to make things interesting.

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Create Green, Soldermasked PCBs With Fritzing

Even though you can easily order a PCB from any one of a dozen board houses and have it on your desk in a few weeks, there’s still a need for home-made circuit boards. If it’s because you have very special or strange requirements, you want to save money, or you need to suffer for your art, you can make printed circuit boards at home. You can even apply soldermask. It’s easy, and [Renzo] is here to show you how.

The beginnings of this tutorial cover well-tread territory such as building a CNC router, laying out a circuit, and cutting a piece of single-sided, copper clad board. If you stopped right there, after milling traces into a board, you would have a functioning circuit. But it wouldn’t look good; a piece of copper does not a PCB make, and you need soldermask. That’s where the real work comes in.

Applying the soldermask meant there needed to be places without soldermask, mostly the vias and through-holes. For this, [Renzo] pulled the copper pad layer out of Fritzing, printed it on a transparency sheet, and finally applied the UV-curing soldermask. This came as a kit, and right now, you can get 10 ml of green, red, blue, yellow, and black UV-curing soldermask, and a UV flashlight for ten dollars on the usual Internet shops. This soldermask was lathered on, rolled out, and exposed with the UV flashlight. After a quick wash in acetone, the result is a perfect PCB.

Automated Cat Feeder Handles Wet Food With Aplomb

A feline’s appetite is rarely sated, and cat owners around the world are routinely treated to an early morning wake up call to remind them of this fact. To solve this problem, many turn to automated feeders. However, such devices usually handle only dry foods, with a simple hopper system. [Vikram Hao] instead went above and beyond, building a fully automated wet food cat feeder.

The device is a great example of effective automation. It’s fully capable of dispensing a single can of cat food, as well as opening the can, serving the food and disposing of the waste in an integrated bin. Currently, it has a maximum capacity of 9 cans, though this can be increased by simple alterations to the hopper and trash bin. Unsurprisingly, all manner of steppers, servos and brushed motors work in concert to achieve this feat. An Arduino Mega 2560 serves as the brains, providing plenty of IO to run everything as easily as possible.

[Vikram] reports that both the owner and the cat are overjoyed with the invention. We’ve seen a few builds before, with some even featuring armor plating. Video after the break.

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Kid Rover Is Six Wheels Of Awesome

There are plenty of ways to go about learning to TIG weld. Most involve a series of practice parts making butt joints and welding together various sections of pipe. [Kris Temmerman] decided to go a little bit farther, however. The result is a kid rover that’s sure to be the envy of every neighbourhood child for a few zipcodes around.

The chassis is an all-aluminium affair, making TIG welding the perfect choice for the job. Of course, [Kris] wasn’t content to simply build a basic go-kart or buggy. This sweet ride is inspired by the rocker-bogie designs of NASA’s Mars rovers, giving it the ride height and flexibility to roam over serious obstacles. Naturally, there’s six-wheel drive and four-wheel steering to complete the dynamic package. It should also be noted that yellow wheels are a stunning design choice that we just don’t see enough of.

It’s a beautifully crafted vehicle, and a testament to [Kris]’s machining and design skills. We can’t wait to see it given a shakedown run on the muddy fields of Belgium. If you’re eager to start your own rocker-bogie build, NASA’s got the open source designs to get you started. Video after the break.

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Hacker Abroad: Visiting Espressif And Surprising Subway Ads

Thursday was my final day in Shanghai. After spending all of Wednesday at Electronica Asia, I headed over to the Espressif Headquarters which is just one subway stop away. This is of course the company behind the well-known ESP8266 and its younger sibling, the ESP32. My host was Ivan Grotkothov, Director of Software Platforms. The backstory on how he found his way to the company is truly interesting, as are the stories he shared on some of the legend and lore surrounding the WiFi capable chips the company makes — and the new one whose existence just leaked out this week.

Join me below for that and few other fun things from my last day in this city of 26 million people.

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Retrotechtacular: Nellie The School Computer

When did computers arrive in schools? That should be an easy question to answer, probably in the years around 1980. Maybe your school had the Commodore Pet, the Apple II, or if you are British, the Acorn BBC Micro in that period, all 8-bit microcomputers running a BASIC interpreter. That’s certainly the case for the majority of schools, but not all of them. In early 1969 the BBC’s Tomorrow’s World visited a school with a computer, and in both technology and culture it was a world away from those schools a decade later that would have received those BBC Micros.

The school in question was The Forrest Grammar School, Winnersh, about 35 miles west of London, and the computer in question was a by-then-obsolete National Elliott 405 mainframe that had been donated four years earlier by the British arm of the food giant Nestlé. The school referred to it as “Nellie” — a concatenation of the two brand names. It seems to have been the preserve of the older pupils, but the film below still shows the concepts of its operation being taught at all levels. We get a brief look at some of their software too — no operating systems here, everything’s machine code on paper tape — as a teacher plays a reaction timer game and the computer wins at noughts and crosses (tic-tac-toe). One of them has even written a high-level language interpreter on which younger children solve maths problems. Of course, a 1950s mainframe with hundreds or thousands of tubes was never a particularly reliable machine, and we see them enacting their failure routine, before finally replacing a faulty delay line.

This is a fascinating watch on so many levels, not least because of its squeaky-clean portrayal of adolescent boys. This is what teenagers were supposed to be like, but by the late 1960s they must in reality have been anything but that away from the cameras. It’s a contrast with fifteen or twenty years later, the computer is seen as an extremely important learning opportunity in sharp opposition to how 8-bit computers in the 1980s came to be seen as a corrupting influence that would rot young minds.

Of course, these youngsters are not entirely representative of British youth in 1969, because as a grammar school the Forrest was part of the top tier of the selective education system prevalent at the time. There would certainly have been no computers of any sort in the local Secondary Modern school, and probably the BBC’s portrayal of the pupils would have been completely different had there been. In 1974 the Government abolished the grammar school system to create new one-size-fits-all comprehensive schools, one of which the Forrest school duly became. Following the vagaries of educational policy it is now an Academy, and there is probably not a room within it that does not contain a computer.

So what of Nellie? Because of the film there are plenty of online references to it in 1969, but we could only find one relating to its fate. It was finally broken up in 1971, with the only surviving component being a delay line. More than one Elliott machine survives in museum collections though, and your best chance in the UK of seeing one is probably at the National Museum Of Computing, in Bletchley.

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Hackaday Podcast Ep11 – Weird Keyboards, Salvaging LCD Screens, And Mike Interviews Ivan Of Espressif In Shanghai

With our intrepid Editor in Chief Mike Szczys off being kind of a big deal in China, Managing Editor Elliot Williams is joined by Staff Writer Tom Nardi to talk about all the hacks that were fit to print over the past week. Join us as we talk about the wide world of custom mechanical keyboards, reviving a woefully antiquated display technology, building your own RC transmitter out of stuff you have laying around the lab, and the unexpected parallels between Pepto Bismol and rocket fuel. We’ll also look at what it takes to build a robust embedded system, and see if we can’t figure out a way to draw schematics worth looking at. Plus, hang around until the end of the episode to hear Mike interview the man instrumental in getting the ESP8266 to play nice with Arduino, and now running firmware for the ESP32.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (76 MB)

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