Misc Hacks

4137 Articles

Flywheel Trebuchet Spins Right Round

October 2, 2020 by 7 Comments

Most of us gained a familiarity with siege weapons from Age of Empires, and the march of technology has meant these relics aren’t typically seen on modern battlefields. However, development continues apace in the enthusiast community, and [Tom Stanton]’s latest trebuchet design puts a different spin on launching projectiles at speed.

The design takes advantage of the flywheel as an energy storage device. The flywheel is spun up to speed using a hand crank, through a timing belt and a set of hybrid 3D printed and CNC aluminium gears. Once spun up to sufficient angular velocity, a trigger releases the tennis ball payload from a sling, flinging it forth at speeds over 180 miles per hour.

Moving on from classical materials such as wood and nails, [Tom]’s latest design relies on aluminium in an effort to build something that won’t rot when left outside in the rain. The use of aluminium profiles also makes adjustment and redesigns easy, while providing the necessary adjustments to dial in things like release point and belt tension. We’ve featured a few different designs over the years; the walking-arm trebuchet is perhaps the most oddball of all. Video after the break.

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Reel In The Years With A Cassette Player Synth

October 1, 2020 by 9 Comments

Variable-speed playback cassette players were already the cool kids on the block. How else are you going to have any fun with magnetic tape without ripping out the tape head and running it manually over those silky brown strips? Sure, you can change the playback speed on most players as long as you can get to the trim pot. But true variable-speed players make better synths, because it’s so much easier to change the speed. You can make music from anything you can record on tape, including monotony.

[schollz] made a tape synth with not much more than a variable-speed playback cassette player, an Arduino, a DAC, and a couple of wires to hook it all up. Here’s how it works: [schollz] records a long, single note on a tape, then uses that recording to play different notes by altering the playback speed with voltages from a MIDI synth.

To go from synth to synth, [schollz] stood up a server that translates MIDI voltages to serial and sends them to the Arduino. Then the DAC converts them to analog signals for the tape player. All the code is available on the project site, and [schollz] will even show you where to add Vin and and a line in to the tape player. Check out the demo after the break.

There’s more than one way to hack a cassette player. You can also force them to play full-motion, color video.

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State Of The Art For Nixies Gets A Boost From Dalibor Farny’s Supersize Prototype

September 28, 2020 by 14 Comments

Never one to pass up on a challenge, artisanal Nixie tube maker [Dalibor Farný] has been undertaking what he calls “Project H”, an enormous array of 121 Nixie tubes for an unnamed client. What’s so special about that? Did we mention that each Nixie is about the size of a sandwich plate?

Actually, we did, back in May when we first noted Project H in our weekly links roundup. At that time [Dalibor] had only just accepted the project, knowing that it would require inventing everything about these outsized Nixies from scratch. At 150 mm in diameter, these will be the largest Nixies ever made. The design of the tube is evocative of the old iconoscope tubes from early television history, or perhaps the CRT from an old oscilloscope.

Since May, [Dalibor] has done most of the design work and worked out the bugs in a lot of the internal components. But as the video below shows, he still has some way to go. Everything about his normal construction process had to be scaled up, so many steps, like the chemical treatment of the anode cup, are somewhat awkward. He also discovered that mounting holes in the cathodes were not the correct diameter, requiring some clench-worthy manual corrections. The work at the glassblower’s lathe was as nerve wracking as it was fascinating; every step of the build appears fraught with some kind of peril.

Sadly, this prototype failed to come together — a crack developed in the glass face of the tube. But ever the pro, [Dalibor] took it in stride and will learn from this attempt. Given that he’s reduced the art of the Nixie to practice, we’re confident these big tubes will come together eventually.

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Sliding Screen Has Wheels, Will Travel

September 28, 2020 by 5 Comments

For a recent event, [MakerMan] was tasked with creating an interactive display that could move back and forth along an image of the Moscow skyline to highlight different points of interest. The end result is certainly gorgeous, but since this is Hackaday, we were more excited to see all the behind the scenes video of how it was built.

As with many of his projects, this one started with little more than scrap parts. Two metal I-beams were welded together to make a track, and a wheeled cart was fashioned to ride on it. Using a belt and pulley system that’s not unlike a scaled up version of what you might see on a desktop 3D printer, the motor in the cart is able to move the arrangement back and forth with minimal slop.

Installing the motor and pulley in the cart.

The cart actually holds all of the electronics in the project, including the power supplies, MA860H motor controller, a pair of endstop switches, and the Arduino that pulls it all together. A drag chain is used to keep the wires tight to the side of the rail without getting tangled up in anything.

[MakerMan] doesn’t explain much of the software side of this one, though we suppose he might only have been contracted to develop the hardware. But towards the end of the video you can see how the cart, now with large touch screen display mounted on top, moves back and forth when the appropriate commands are sent to the Arduino.

We’re not really sure what application such a contraption would have for the average hacker, but that doesn’t mean we can’t be jealous. There’s just something about huge illuminated screens that just speaks to us.

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Already Have That Book? Get The ISBN 411 Over IoT

September 27, 2020 by 16 Comments

Have you ever been at the bookstore and stumbled across a great book you’ve been looking for, but had a nagging feeling that you already had it sitting at home? Yeah, us too. If only we’d had something like [Kutluhan Aktar]’s ISBN verifier the last time that happened to say for sure whether we already had it.

To use this handy machine, [Kutluhan] enters the International Standard Book Number (ISBN) of the book in question on the 4 x 4 membrane keypad. The Arduino Nano 33 IoT takes that ISBN and checks it against a PHP web database of book entries [Kutluhan] created with the ISBN, title, author, and number of pages. Then it lets [Kutluhan] know whether they already have it by updating the display from a Nokia 5110.

If you want to whip one of these up before your next trip to the bookstore, this project is completely open source down the web database. You might want to figure out some sort of enclosure unless you don’t mind the shy, inquisitive stares of your fellow bookworms.

Stalled out on reading because you don’t know what to read next? Check out our Books You Should Read column and get back to entertaining yourself in the theater of the mind.

Via r/duino

Food Dispenser Shakes And Rattles

September 27, 2020 by 17 Comments

[Elite Worm] follows a strict diet that involves regularly mixing dry ingredients in varying proportions. The task grew tedious, and thus automation became a tantalising prospect. Enter the DIY shaking food dispenser.

The machine has a simple touch screen interface, with an Atmega328P running the show behind the scenes. The user can store a series of profiles, which each correspond to a different mixture of four base ingredients. Dealing with dry ingredients like oats, chia, and flax, shaking is often necessary to get things moving. To achieve this, the rig packs a hefty DC motor up top, which turns an eccentric shaft, shaking the whole rig. Each ingredient hopper has a servo-controlled nozzle, so ingredients can be dispensed in turn, with a load cell in the base measuring the weight delivered.

It’s a neat system, though [Elite Worm] notes that the device shakes just a little too much, and suspects it won’t hold up in the long term. We suspect a less violent, higher frequency vibration might be less hard on the components, but we’re sure there’ll be some quality engineering going into the next build. We’ve seen [Elite Worm]’s work here before, too. Video after the break.

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