Misc Hacks

4125 Articles

Old Barcode Scanner Motherboards Live Again

September 21, 2022 by 1 Comment

Sometimes, hacking is just for the pleasure of diving into the secrets of old hardware. That was very much the case when [glitch] and a friend started hacking on some old Intel 8080 boards that had been living in the junk pile for too long.

The boards in question were motherboards from Identicon barcode scanners, running the Intel 8080 CPU. Hacking on the 8080 is a little different, with the ancient CPU requiring three separate voltages to run. However, with the power rails figured out and power applied, it was possible to get the old boards up and running.

The boards were first run with test ROMs which showed the 8080 CPU to be functional. The ROMs hosted a simple program which got the 8080 to spit out the word “HELO” on to an HP HDSP-2416 ASCII character display. From there, the barcode scanner boards were installed in a chassis and hooked up to a bigger Siemens character display, and the memory was mapped out.

The result was that [glitch] and co were able to largely reverse engineer the Identicon hardware, learning it was fairly similar to the Intel MCS-80 reference design of the era. They were able to get code running on the platform, access the RAM, and fit a larger 8-character display. However, without the original barcode scanner attachment, the boards weren’t able to return to their original duty.

As far as hacks go, it’s pretty old school. The boards don’t talk to Twitter, nor run the lights or help with the dishes. However, plenty of fun was had seeing if this old metal could be made to follow instructions once more. Hacking for the pleasure of it is always a good thing by our book!

A 3D Printed Marble Run Features Neat Elevator Linkage

September 21, 2022 by 20 Comments

There’s seldom anything as joyful and relaxing to watch as a simple marble run. Of course, the thing about letting marbles fall under gravity is that you eventually need to lift them back up again. The Marblevator has a mechanism that does just that.

Overall, the build features a relatively simple marble run. It consists of just six 3D printed ramps which the marble tumbles down in just a few seconds. However, the real magic is in the mechanism that restores the marbles from the bottom of the run all the way back to the top.

A motor turns a gear, which then rotates a crank leading to a multi-link rhombus. On one corner of the rhombus is a small protrusion with a magnet attached, which picks up the marbles from the bottom of the run. As the mechanism turns, the rhombus shifts and brings the marble-carrying arm to the top of the marble run. There, it’s grabbed by another magnet, which holds the marble for a moment before letting it drop back down through the run.

It’s a simple project that nonetheless would make a brilliant desk toy. It’s also a great way to learn about linkage analysis and designing such systems on your own. If you’re big into marble runs, you might also consider procedurally generating them. Video after the break.

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3D Printed Strain-Wave Gearbox Turns Up The Torque

September 17, 2022 by 6 Comments

3D printers are good for a lot of things, but making parts for power transmission doesn’t seem to be one of them. Oh sure, some light-duty gears and timing belt sprockets will work just fine when printed, but oftentimes squooshed plastic parts are just too compliant for serious power transmission use.

But that’s not a hard and fast rule. In fact, this 3D-printed strain-wave transmission relies on the flexibility of printed parts to work its torque amplification magic. In case you haven’t been briefed, strain-wave gearing uses a flexible externally toothed spline nested inside an internally toothed stationary gear. Inside the flexible spline is a wave generator, which is just a symmetrical cam that deforms the spline so that it engages with the outside gear. The result is a high ratio gear train that really beefs up the torque applied to the wave generator.

It took a couple of prototypes for [Brian Bocken] to dial in his version of the strain-wave drive. The PLA he used for the flexible spline worked, but wasn’t going to be good for the long haul. A second version using TPU proved better, but improvements to the motor mount were needed. The final version proved to pack a punch in the torque department, enough to move a car. Check it out in the video below.

Strain-wave gears have a lot of applications, especially in robotic arms and legs — very compact versions with the motor built right in would be great here. If you’re having trouble visualizing how they work, maybe a Lego version will clear things up.

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Making Variable Capacitors By Stretching Aluminium Cans

September 15, 2022 by 33 Comments

Sometimes when you need a component, the best way to get it is by building it yourself. [North Carolina Prepper] did just that, creating his own trombone-style variable capacitor by stretching some aluminium beverage cans. 

The requirement was for a 26 pF to 472 pF capactitor, for a radio transmitting from 7 MHz to 30MHz. The concept was to use two beverage cans, one sliding inside the other, as a capacitor, with an insulating material in between.

To achieve this, a cheap exhaust-pipe expanding tool was used to stretch a regular can to the point where it would readily slide over an unmodified can, plus some additional gap to allow for a plastic insulating sheet in between. Annealing the can is important to stop it tearing up, but fundamentally, it’s a straightforward process.

The resulting trombone capacitor can readily be slid in and out to change its capacitance. The build as seen here achieved 33 pF to 690 pF without too much hassle, not far off the specs [North Carolina Prepper] was shooting for.

Radio hams are very creative at building their own equipment, especially when it comes to variable capacitors. Video after the break.

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Today’s The Day You Finally Learn Quaternions

September 5, 2022 by 44 Comments

If you’ve ever dealt with orbital mechanics or sophisticated computer graphics, you’ve probably run across the math term quaternions. [Anyleaf] has a guide to the practical use of this math concept which focuses more on practicality than theory. We like it!

Quaternions are one of at least two ways to model rotations in a 3D space. Most people are familiar with the classic Euler angles which cover yaw, pitch, and roll. However, this method is prone to some ambiguities — in other words, there are multiple ways to go from one Euler state to another and all are equally valid. In addition, Euler angles are prone to gimbal lock where two of the axes are parallel and, thus, don’t have a different effect on the object’s orientation. There are several ways to combat that including the use of quaternions.

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The 7805 Is Dead! Long Live The 7805!

September 5, 2022 by 70 Comments

The 78XX series of regulators are very handy to use. If you need, say, a 5V regulator, you grab a 7805, add a capacitor for stability, and send in enough voltage for the regulator to work with. Cheap and easy. However, the part is not without its faults.

A stock 7805 can’t convert 5.1V to 5V. You need to have a good bit more voltage coming in. But the more voltage you put in, the more the part is going to dump out as heat. So running from 9V is going to be cooler than running from 24V. All that heat isn’t very energy efficient on batteries, either. [Stefan] wanted to do better, so he made a drop-in replacement for these venerable regulators some time ago. But he’s recently made the board layouts available so you can build your own replacement, too.

The device accepts 4.5 to 16V, and you can select the output voltage using two resistors. You can draw up to 2A out of the regulator, which is more than you can say for a stock 7805.

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Hackaday Prize 2022: Drying Clothes With Ultrasound

September 4, 2022 by 29 Comments

Clothes dryers are great, and a key part of modern life, but they do use a lot of energy. [Mike Rigsby] decided to see if there was a more efficient method of drying clothes that could compete with resistive heating for efficiency. Thus, he started work on an ultrasonic clothes dryer.

In early testing, he found ultrasonic transducers could indeed blast droplets of moisture away from fabric, effectively drying it. However, unlike heat, the ultrasonic field doesn’t effectively permeate through a pile of clothes, nor can it readily be used with a spinning drum to dry many garments at once.

[Mike]’s current experiments are centered around using a basket-type system, with a bed of ultrasonic transducers at the bottom. The idea is that the basket will shake back and forth, agitating the load of clothing and allowing the different garments to effectively contact the transducers. It’s still a work in progress, but it’s an interesting approach to the problem. We’d love to see a comparison of the energy use of a full-scale build versus a regular dryer.

We’ve heard of the ultrasonic drying concept before, too, with the Department of Energy researching the matter. It could just be that we’ll all be using ultrasonic dryers in decades to come!

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