Vacuum Forming With 3D Printer Filament

December 11, 2021 by Tom Nardi 17 Comments

Even if they don’t have one themselves, we’d wager the average Hackaday reader is at least vaguely aware of how a vacuum former works on a fundamental level. You heat up a plastic sheet until it’s soft, then use a vacuum pump to pull the ductile material down onto an object and hold it there while it cools off. It’s easy to build a vacuum forming rig yourself, but small commercial units are cheap enough that it might not be worth your time. If everything goes to plan, the technique is a quick and effective way of duplicating items around the home and shop.

But we were recently tipped off to a variation of this classic technique that’s certainly worth further research. As demonstrated in a recent video, [Nathan Martinez] shows how 3D printed sheets can be used in place of the 5″ x 5″ squares of thermoplastic film that his imported vacuum former was designed to use. It’s easy enough to do: just model up a square with the appropriate 2D dimensions in your CAD package of choice, and extrude it to a height of about .5 mm.

A printed mesh pattern could be used to form custom shaped filters or strainers.

So what’s the advantage? Well for one thing, it’s cheaper. Though admittedly, not by much. Going rate on Amazon seems to be about 90 cents per sheet for the real stuff, and some back of the envelope math shows the printed version coming in at around 30 cents given nominal filament costs. Whether or not those savings are worth the extra effort is certainly debatable.

But that’s not really the most interesting part. With printed sheets loaded into the vacuum former, you’ve got access to a much wider array of materials to work with. For example, [Nathan] shows off some very interesting flexible pieces he was able to produce using sheets of TPU. You can also experiment with different surface textures. These can not only be used to give your vacuum formed pieces a bit of interesting visual flair, but could actually have some practical applications. In the video we see how a printed mesh could be formed over a piece to create a conformal air vent or filter.

To be sure, there’s some room for improvement here. Not all the pulls were successes, and [Nathan] says getting the printed sheets up to the proper temperature can be tricky. But when it works, it works quite well, and we think there could be some untapped potential in this unexpected melding of new and old methods of at-home plastic production.

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The supersonic trebuchet being modeled in software

Supersonic Projectile Exceeds Engineers Dreams: The Supersonic Trebuchet

December 1, 2021 by Ryan Flowers 62 Comments

Have you ever sat down and thought “I wonder if a trebuchet could launch a projectile at supersonic speeds?” Neither have we. That’s what separates [David Eade] from the rest of us. He didn’t just ask the question, he answered it! And he documented the entire build in a YouTube video which you can see below the break.

The trebuchet is a type of catapult that was popular for use as a siege engine before gunpowder became a thing. Trebuchets use a long arm to throw projectiles farther than traditional catapults. The focus has typically been on increasing throwing distance for the size of the projectile, or vice versa. But of course you’re here to read about the other thing that trebuchets can be used for: speed.

How fast is fast? How about a whip-cracking, sonic-booming speed in excess of 450 meters per second! How’d he do it? Mostly wood and rubber with some metal bits thrown in for safety’s sake. [David]’s video explains in full all of the engineering that went into his trebuchet, and it’s a lot less than you’d think. There’s a very satisfying montage of full power trebuchet launches that make it audibly clear that the projectile being thrown is going well past the speed of sound, with a report quite similar to that of a small rifle.

[David]’s impressive project and presentation makes it clear that all one has to do to build a supersonic trebuchet is to try. Just be careful, and watch where you shoot that thing before you put somebody’s eye out, ok?

Speaking of things that can go unexpectedly fast, check out these unpowered RC gliders that approach the speed of sound just feet off the ground. And thanks to [Keith] for the awesome Tip!

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Vision Impaired Electronics Engineer Shows The Way To Get Things Done

November 26, 2021 by Ryan Flowers 18 Comments

A funny thing happens as the average electronics hobbyist gets older: Their eyes- well they just don’t work the same as they used to. But what if your life started out with compromised vision? In this epic forum post (Google translated from Polish to English), we meet nearly blind hacker [Urgon]. He goes into great detail about his condition and how it affects not just his daily life, but also his abilities as an electronics engineer. Or conversely, how it doesn’t.

[Urgon]’s origin story is familiar. At eight years old, he disassembled his first television. His self-education continued by using his remaining vision to soak up every bit of literature about electronics that he could get his hands on. A well-intentioned but protective mother kept him away from soldering irons, fearing that the close proximity to his good eye might not bode well for his remaining vision.

If Urgon can solder 0805's, so can you! — If Urgon can solder SOIC’s 0805’s, so can you!

Despite a failed eye, and his other having quite severe glaucoma, [Urgon] has persevered. He uses assistive technologies as you’d expect, but notes that in more recent times some excellent free software has surpassed some of the commercial products he used in the past.

While even the sighted among us often shy away from SMD components, [Urgon] dives right in. SOIC packages and 0805 parts don’t hold him back. Bright LED flashlights, zooming in with his smart phone, and surely a healthy dose of patience make his hackery possible.

That’s not to say that [Urgon] hasn’t had some noteworthy incidents. He’s suffered electric shock from the 400 V capacitors in an ATX PSU, burned his face with his soldering iron, and even managed to step on a DIP package. Barefoot. Yes, the pins were facing up.

But wait- there’s more! In this follow-up post, [Urgon] discusses more assistive/adaptive technologies and how hackers like you and I can focus our efforts on things the vision impaired will find most helpful.

Our hats are off to [Urgon] and those like him who persevere despite the odds. We can all learn from [Urgon]’s hacker spirit and his dedication to the craft. We recently covered some blind software hackers who have taken it upon themselves to fly passenger jets– virtually, of course!

Thanks to [Moryc] for the excellent tip!

A Rotary Phone As A Computer Peripheral

November 26, 2021 by Jenny List 5 Comments

It’s an age-old conundrum for anyone working with retro hardware: preserve its original condition or not? The answer depends so often on a complex mix of how rare, obsolete or unusable the device is in its original form , and what the intended use for the device will be. For [Typhon Mind] who needed a novelty method of recording best wishes at a wedding through an old dial phone there was no need for it to be entirely original, so the solution was to turn it into a USB device for a host computer.

Out went the original circuitry, and in came a USB hub, a USB audio interface, and an Arduino. The original earpiece would suffice, but the microphone was replaced with a more modern one. The Arduino will register the cradle switch, and also power a set of LED addressable lights under the unit.

The result is a phone that retains all its looks, but has a new life as a PC peripheral. We’d venture to suggest that also using the Arduino to read the dial and produce DTMF tones might make it a valid peripheral for a VOIP application and complete the transformation, but that’s something that could be done at a later date. Maybe it could even be given a GSM makeover.

The Pros And Cons Of A Power Flush Toilet

November 20, 2021 by Lewin Day 36 Comments

By and large, toilet design hasn’t radically changed in a good long time. The problem was considered solved, and society moved on. However, [Handy Geng] was tasked by a friend to build a toilet with an extra-powerful flush, so he went ahead and did just that.

The concept is simple; the water tank in the custom-built toilet can be charged with pressurized air from a compressor when an more powerful flush is needed. Then, when the lever is pulled on that flush, the water will blast into the bowl with significantly more ferocity than usual.

[Handy Geng] also notes a further benefit from the system. By bolting down the toilet lid, using a gasket to seal it to the toilet bowl, the air pressure system can be used to blast out blockages and clogs.

However, there are some drawbacks. The toilet is nearly entirely constructed out of steel, a material that generally isn’t the first choice when working with water or bodily fluids. Additionally, the power flush mode tends to end up with water spraying out of the bowl due to the intensity of the spray.

Regardless, it goes to show that the toilet design is still an active area of research, and that we needn’t settle for the toilets we have today. More powerful, more capable models are just around the corner if we want them. Video after the break.

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Arduino Library Makes Digital Rain Like It’s 1999

November 17, 2021 by Tom Nardi 31 Comments

There’s going to be a new Matrix movie in theaters next month, and you know what that means: we’re about to see a whole new generation get obsessed with the franchise’s iconic “Digital Rain” effect. Thanks to modern advertisement technology, expect to see lines of glittering text pouring down the displays of everything from billboards to gas pumps pretty soon.

For those of us who’ve just been looking for an excuse to break out the old Matrix screensavers, you might as well get a jump on things using this handy Arduino library for the ESP8266 and ESP32. Developed by [Eric Nam], it lets you start up a digital rainstorm on displays supported by the TFT_eSPI library as easily as running digitalRainAnim.loop().

You can even install the library through the Arduino IDE, just open the Library Manager and search for “Digital Rain” to get started. You’ve still got to hook the display up to your microcontroller, but come on, [Eric] can’t do it all for you.

Looking at the examples, it seems like various aspects of the animation like color and speed can be configured by initializing the library with different values. Unfortunately we’re not seeing much in the way of documentation for this project, but by comparing the different examples, you should be able to get the high points.

While our first choice would certainly be a wall of green alphanumeric LED displays, we can’t help but be impressed with how easy this project makes it to spin up your own little slice of the Matrix on the workbench.

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Treasure Hunting With A Handful Of Common Components

November 15, 2021 by Adam Zeloof 16 Comments

Sometimes simpler is better — when you don’t need the the computational power of an onboard microcontroller, it’s often best to rely on a simple circuit to get the job done. With cheap Raspberry Pis and ESP32s all over the place, it can be easy to forget that many simpler projects can be completed without a single line of code (and with the ongoing chip shortage, it may be more important now than ever to remember that).

[mircemk] had the right idea when he built his simple induction-balance metal detector. It uses a couple of 555 timers, transistors, and passives to sense the presence of metallic objects via a coil of wire. He was able to detect a coin up to 15 cm away, and larger objects at 60cm — not bad for a pile of components you probably have in your bench’s spare parts drawer right now! The detector selectivity can be tuned by a couple of potentiometers, and in true metal detector fashion, it has a buzzer to loudly blare at you once it’s found something (along with a LED, in case the buzzer gets too annoying).

All in all, this metal detector looks like a terribly fun project — one perfectly suited to beginners and more seasoned hackers alike. It serves as a great reminder that not every project needs WiFi or an OLED display to be useful, but don’t let that stop you from overdoing things! If touchscreens are more your speed, [mircemk] has got you covered with a smartphone-integrated version as well.

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