Interactive CNC Foam Cutter Churns Out Abstract Art

July 11, 2020 by Adil Malik 3 Comments

Foam is certainly an indispensable raw material for various craft and construction projects. Any serious sculptor however, inevitably grows tired of grinding through a foam block using a simple preheated utensil. The next step up, is to assemble a simple but thoroughly effective hot wire cutting contraption, formed out of a thin guitar wire held taut on a “C” shaped mounting frame. Finally, the addition of some electronics to regulate the power delivery makes this simple tool useful for most settings.

[Freddie] has taken this basic idea a step further, by building a complete multi-axis CNC foam cutter intended as an interactive exhibit on computational art. The CNC has the traditional three Cartesian axes but the platform hosting the foam piece can also rotate, introducing an additional degree of freedom. As this is indented to be controlled by attendees, there is no G-code in the mix, rather the inputs of an Xbox controller are applied directly to the work piece.

What is very interesting is how the resulting tool path is visualised and displayed. [Freddie] explains that while the user input tool path could be generated and displayed as equivalent G-code, it does not capture and convey the inherent organic nature of the finished pieces. The solution [Freddie] came up with is to display the toolpath much like a series of musical notes!

We would have loved to have a go at this machine in person, but seeing that isn’t possible in the current circumstances, you can either build a simpler machine we featured earlier or [Freddie] could perhaps fire up a camera and let us control it via the interweb, with a live video feed ofcourse!

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Hack Together Your Own Bat Signal

July 11, 2020 by Orlando Hoilett 27 Comments

Bats use echolocation to see objects in front of them. They emit an ultrasonic pulse around 20 kHz (and up to 100 kHz) and then sense the pulses as they reflect off an object and back to the bat. It’s the same type of mechanism used by ultrasonic proximity sensors for object-avoidance. Humans (except perhaps the very young ones) can’t hear the ultrasonic pulses since the frequency is too high, but an inexpensive microphone in a simple bat detector could. As it turns out bat detectors are available off the shelf, but where’s the fun in that? So, like any good hacker, [WilkoL] decided to build his own.

[WilkoL’s] design is composed primarily of an electret microphone, microphone preamplifier, CD4040 binary counter, LM386 audio amplifier, and a speaker. Audio signals are analog and their amplitudes vary based on how close the sound is to the microphone. [WilkoL] wanted to pick up bat sounds as far away as possible, so he cranked up the gain of the microphone preamplifier by quite a bit, essentially railing the amplifiers. Since he mostly cares about the frequency of the sound and not the amplitude, he wasn’t concerned about saturating the transistor output.

The CD4040 then divides the signal by a factor of 16, generating an output signal within the audible frequency range of the human ear. A bat signal of 20 kHz divides down to 1.25 kHz and a bat signal of up to 100 kHz divides down to 6.25 kHz.

He was able to test his bat detector with an ultrasonic range finder and by the noise generated from jingling his keychain (apparently there are some pretty non-audible high-frequency components from jingling keys). He hasn’t yet been able to get a recording of his device picking up bats. It has detected bats on a number of occasions, but he was a bit too late to get it on video.

Anyway, we’re definitely looking forward to seeing the bat detector in action! Who knows, maybe he’ll find Batman.

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Aerodynamics For Dummies

July 11, 2020 by Al Williams 39 Comments

We don’t know if aerodynamics is really a subject for dummies, per se, but if you are interested in flying or building drones and model aircraft, [Jenny Ma’s] new video that you can see below will help you get an easy introduction to some key concepts. (Embedded below.)

The show starts with coverage of lift, thrust, and drag, but moves on to topics such as stalling and coffin corners. If you have a pilot ticket, you might not learn a lot of new things, but for the rest of us, there are some interesting nuggets that you might not have known or might have forgotten from your physics classes in high school.

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Hackaday Made Me Buy It!

July 11, 2020 by Elliot Williams 44 Comments

Reading Hackaday is great! You get so many useful tips from watching other people work, it’s truly changed nearly everything about the way I hack, especially considering that I’ve been reading Hackaday for the past 15 years. Ideas, freely shared among peers, are the best of the free and open-source hardware community. But there’s a dark downside: I’m going CNC mill shopping.

It all started with [Robin]’s excellent video and website tutorial on his particular PCB DIY procedures. You see, I love making PCBs at home, because I’m unafraid of chemistry, practiced with a rolling pin and iron, and super-duper impatient. If I can get a board done today, I’m not waiting a week, even if that means an hour of work on my part.

Among other things, he’s got this great technique with a scriber pen and a cleverly designed registration base that make it easy for him to do nearly perfectly aligned two-sided boards with a resolution approaching etching. The ability to make easy double-sided boards, with holes drilled, makes milling attractive, but the low resolution of v-cutter milled boards has been the show-stopper for me. If that’s gone, maybe it’s time to take a serious look.

And heck, making PCBs is really just the tip of the iceberg for what I’d want to do with a CNC mill. Currently, I do dodgy metalworking with an x-y table and a drill press, some of which may someday land me in the hospital. But if I had a mill, I’d be doing all sorts of funny wood joinery and who knows what else. I lack experience with a mill, but coincidentally, we just had a Hack Chat on Linux for machine tools this week. You see? It’s all conspiring against me.

The only question left is what I should get. I’m looking at the ballscrew 3040 range of CNCs, and maybe upgrading the spindle. I’d like to mill up to aluminum, but don’t really need steel. What do you think?

A Desk Calendar With A Difference

July 11, 2020 by Jenny List 9 Comments

With the office computer revolution now many decades old, many of the items that once stood on a typical desk are now part of history. The typewriter, the Rolodex, and the desk calendar have all been subsumed by computers and mobile phones. This electronic desk calendar is perhaps an exception, created as a promotional device for the RT-Thread IoT OS. It features an interesting take on a perpetual calendar, with an array of days spanned by a sliding frame such that any month’s days of the week can be depicted. The days are touch buttons, and can be used to bring up the information on an e-ink display.

Behind it all is a WinnerMicro W600 WiFi-enabled system-on-chip, that runs the aforementioned RT-Thread IoT OS. This OS is a bit of a mystery, according to its Wikipedia page it’s an open-source project from China with ten years of development behind it, but this appears to be the first time we’ve seen it here at Hackaday. Anyone using it?

We like this project though, for its perpetual calendar, and for its re-imagining of a bygone desk accoutrement with an e-ink display to conserve battery. It’s not the first e-ink calendar we’ve seen, this previous one used a Raspberry Pi.

A ZX80 With A Proper Case

July 11, 2020 by Jenny List 14 Comments

A popular project among Hackaday readers is to recreate a piece of home computing or gaming hardware from the past, and in that endeavour we’ve seen some truly amazing projects. Usually they take the form of bare PCBs or custom cases that look nothing like the original, but not [Cees Meijer]’s Sinclair ZX80 clone. It sports a 3D printed replica of the original computer’s vacuum-formed case, which from a distance you could be mistake for the real thing.

Internally it’s not a ZX80 at all, but a Raspberry Pi Zero running an emulator. But with a case like this one that’s not the point. It doesn’t have the full-length PCB of the original but a modern ZX80 membrane keyboard, and the Pi appears to be hiding somewhere in the “hump” used by the Astec UHF modulator on the original. There is more information in a blog post, and the model can be downloaded via Thingiverse. Handily, the files also include the original CAD file from RS DesignSpark, should you wish to modify it to your own tastes. If somebody could mate it with Tynemouth Software’s ZX80 kit then our cup would run over.

Of course, this isn’t the only retrocomputer for which a replacement case can be found.

It’s Time For Watch Clocks To Make A Comeback

July 10, 2020 by Kristina Panos 10 Comments

Along with all the colorful, geometric influence of Memphis design everywhere, giant wristwatch clocks were one of our favorite things about the 80s. We always wanted one, and frankly, we still do. Evidently, so did [Kothe]. But instead of some splashy Swatch-esque style, [Kothe] went the nerdy route by building a giant Casio F-91W to hang on the wall.

Not only does it look fantastic, it has the full functionality of the original from the alarm to the stopwatch to the backlit screen. Well, everything but the water resistance. The case is 3D-printed, as are the buckle and the buttons. [Kothe] might have printed the straps, but they were too big for the bed. Instead, they are made of laser-cut foam and engraved with all the details.

Inside there’s a 7″ touch display, a real-time clock module, and an Arduino Mega to make everything tick. To make each of the printed buttons work, [Kothe] cleverly extended a touch sensor module’s input pad with some copper tape. We think this could only be more awesome if it were modeled after one of Casio’s calculator watches, but that might be asking too much. Take a few seconds to watch the demo after the break.

Prefer your clocks less clock-like? Get a handle on the inner workings of this slot machine-based stunner.

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