classic hacks

2705 Articles

Better Debating Through Electronics

May 12, 2019 by 8 Comments

Watch any news panel show these days, and you’ll see that things can very quickly become unruly. Guests compete for airtime by shouting over one another and attempting to derail their opponent’s talking points. [cutajar.sacha] had encountered this very problem in the workplace, and set about creating a solution.

The result is the Debatable Deliberator, and it combines the basics of “Talking Stick” practices with behavioural training through humiliation. Two participants each wear a headband, fitted with electronics. The holder of the magic ball may speak for as long as the timer counts down. If their opponent speaks during this time, their headband reprimands them with gentle slapping to the face. If the holder speaks over their assigned time, they are similarly treated to mechanical slapping.

It’s an amusing way to help police a discussion between two parties, and it’s all made possible with a trio of WeMos D1 ESP8266 boards. The headbands act as clients, while the ball acts as a server and keeps track of how many times each speaker has broken the rules.

WiFi projects such as this one have become much easier in the past few years with the wide availability of chips like the ESP8266. Of course, if you need more grunt, you can always upgrade to the ESP32.

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Edge Lit Pendant, Is, Well… Lit

May 7, 2019 by 3 Comments

Acrylic is a great material. It’s not cheap, but it comes in a wide variety of colours and styles and can be used to make some very attractive projects. [Geek Mom Projects] is a big fan, and whipped up some fun pendants for a high school Maker Faire.

[Geek Mom] has long been a fan of edge-lighting, as it’s a great way to make beautiful glowy projects out of acrylic. In this case a fluorescent acrylic is used with white LEDs to generate an eerie green glow, though it’s also noted that the project can be done with clear acrylic and color-shifting LEDs instead for an equally cool look. If you’re filming a low-budget sci-fi film, this could be just what you need.

The pendants made a great project for young makers to learn about LEDs, electronics, and technologies such as lasercutting that were used to produce the parts. With copper tape used instead of soldering and a CR2032 battery used to eliminate the need for a current limiting resistor, it’s a very accessible project that most teens were able to complete without assistance.

It’s not the first time we’ve seen edge-lit pendants, either. Alternatively, if you need your acrylic bent, there’s a tool for that, too.

Creating A Touch Pad Without Dedicated Hardware

May 2, 2019 by 5 Comments

Year on year, microcontrollers and development platforms are shipping with ever-increasing feature sets. In the distant past, if you wanted an analog to digital converter or a PWM driver, you had to tack extra ICs on to your design. Nowadays, it’s all baked in at the factory. Of course, you may still find yourself working with a platform that lacks capacitive touch inputs. That’s no problem, though – you can do it all without dedicated hardware anyway!

Capacitive touch sensing works by creating an RC oscillator, and allowing the user to affect the capacitance in the circuit through touch or proximity. By sensing the changes in the frequency of the oscillator, it’s possible to determine whether the object or pad is being touched or not. As the capacitance changes can be small, sometimes it’s desired to use a high frequency oscillator, and then pass the output through a frequency divider, which allows changes to be measured more easily by a slower microcontroller.

[Gabriel] does a great job of both explaining the theory involved, as well as presenting a practical way to achieve this with basic hardware. If you need to add touch sensitivity to an existing or otherwise limited platform, this is an easy way to go about doing it. There are definitely some interesting things you can do with the technology, after all.

Parasite ATtiny Resets Your ESP32 For You

May 1, 2019 by 28 Comments

Embedded development can be a tough process. Between weird electrical gremlins, obscure bugs and our own mistakes, it can be a real struggle at times. To keep cognitive loads to a minimum, it’s best to make sure your tools are as simple and easy to use as possible. [tech] got tired of having to push a button to prepare the ESP32 for programming, and decided to solve the problem.

The solution comes via another microcontroller, in this case an ATtiny9. The small device listens in on the ESP32’s serial receiving pin. When it detects the Arduino IDE’s boot sequence on the line, it switches the BOOT0 and RESET lines on the ESP32, emulating the button presses to force it into programming mode.

Once you’ve become accustomed to one-click programming your ESP boards, you’re not going to want to go back. We could imagine this hack being replicated in a tidy piggyback format so it could be moved from board to board as workflow dictates.

If you’ve got an ESP32 lying around and don’t know what to do with it, you could always consider getting into game development.

 

3D Printing A Water Jet Drive

April 30, 2019 by 16 Comments

[Ivan Miranda] is always experimenting with 3D printing, and recently has been taking his work on the water. His latest creation is a racing paddle boat, but its performance left [Ivan] with a need for speed. Cue the development of the 3D printed water jet engine (YouTube link, embedded below).

The basic principle of operation is simple. Water is sucked through an inlet, where it is accelerated by a turbine driven by a brushless motor. This turbine, in combination with stator fins, forces the water through the outlet, propelling the boat forwards in the process.

The first prototype is printed in PLA. Tolerances are good, thanks largely to [Ivan]’s experience and well-calibrated printers. After assembly, the engine is fired up, to great results. After sourcing a series of larger tubs in which to test the device, the engine is finally run up to full throttle and appears more than capable of shifting a serious amount of water.

We’d love to see a proper instrumented thrust test, particularly one that compares the device to other water jet drives on the market. Brushless motors make a great drive solution for RC boats, so we’re sure [Ivan] will be tearing up the lake real soon. Video after the break.

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Hacking A Cheap EBay Frequency Counter

April 30, 2019 by 5 Comments

eBay is a wondrous land, full of Star Wars memorabilia in poor condition, old game consoles at insane markups, and a surprising amount of DIY electronics. [TheHWCave] found himself tinkering with a common frequency counter kit, and decided to make a few choice improvements along the way (Youtube link, embedded below).

The frequency counter in question is a common clone version of [Wolfgang “Wolf” Büscher]’s minimalist PIC design. Using little more than a PIC16F628 and some seven-segment displays, it’s a competent frequency counter for general use. Clone versions often add a crystal oscillator tester and are available on eBay for a fairly low price.

[TheHWCave] found that the modifications were less than useful, and developed a way to turn the tester components into a more useful signal preamp instead. Not content to stop there, custom firmware was developed to both improve the resolution and also add a tachometer feature. This allows the device to display its output in revolutions per minute as opposed to simply displaying in hertz. By combining this with an optical pickup or other RPM signal, it makes a handy display for rotational speed. If you’re unfamiliar with the theory, read up on our phototachometer primer. If you’re looking to modify your own kit, modified firmware is available on Github.

We’ve seen other eBay kit specials modified before. Being cheap and using commodity microcontrollers makes them a ripe platform for hacking, whether you just want to make a few tweaks or completely repurpose the device.

[Thanks to Acesoft for the tip!]

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3D Printing A Lifting Body Aircraft

April 29, 2019 by 17 Comments

When you think of unconventional aircraft, flying wings have had plenty of time in the sun over the last few decades. With striking designs like the B-2 Spirit and F-117A Nighthawk on the flight line, it’s no surprise. The lifting body never really caught on, however, and it languishes in ignominy to this day. Despite their obscurity, [rctestflight] decided to 3D print a few lifting bodies for himself and take them out for a field test (YouTube video, embedded below).

Most aircraft have a body designed with low drag, and wings designed to provide lift. Lifting body aircraft focus the body design on providing that lift and often have no real wing to the design, needing only control surfaces to compliment the body. For this project, several different designs were constructed, with the craft being drop-launched from a multirotor at significant altitude. Initial tests were hamstrung by stability problems, both due to center of gravity issues and uncertain aerodynamic phenomena. The early designs were particularly prone to suddenly entering an unrecoverable flat spin. Later modifications included the addition of further stabilizers, which helped performance somewhat.

3D printing is a great way to experiment with aerodynamic phenomena, as it’s easy to create all manner of complicated geometries to tinker with. [rctestflight] has done solid work developing a basic craft, and we’d love to see the work continue with powered tests and more development. If flying wings are more your jam, though, you can 3D print those too. Video after the break.

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