Acoustic Accordion Becomes MIDI; Oh The Complexity!

February 1, 2017 by Cameron Coward 20 Comments

Everyone knows accordions are cool — they look fly, make neat noises, and get your romantic interests all hot and bothered. What isn’t cool is being relegated to acoustics only. How are you going to play a packed stadium or lay down a crystal clear track like that? You could go out and buy an electric accordion, but even low-end models carry a hefty price tag. But, this is Hackaday, and you know we’re going to be telling you about someone who found a better way.

That better way, shown in a build by [Brendan Vavra], was to take an acoustic accordion and convert it to MIDI. The base for his build was a decent full-size acoustic accordion purchased on eBay for just $150. Overall, it was in good mechanical condition, but some of the reeds were out of tune or not working at all. Luckily, that didn’t matter, since he wouldn’t be using them anyway. Don’t be fooled in the demo video below; it sounds like he’s playing the acoustic according but notice he’s not pumping those bellows! However, the bellows isn’t useless either since it can feed data back as a MIDI input.

[Brendan’s] build plan called for an Arduino Mega to be tied to a series of photo-interrupters that would detect button pushes and fire MIDI signals. But, first he had to take the thing apart — no small task, given the complexity of the instrument. The accordion has 120 buttons, and they’re not interchangeable, which means he had to carefully keep track of them as they were disassembled.

Continue reading “Acoustic Accordion Becomes MIDI; Oh The Complexity!” →

Horten Fyr Is Norwegian For Blinkie

January 31, 2017 by Elliot Williams 5 Comments

Our Norwegian is pretty weak, so we struggled a little bit with the documentation for a big public LED art project in the lighthouse (translated) in Horten, Norway. But we do speak the universal language of blinkies, and this project has got them: 3,008 WS2812b LEDs ring the windows at the top of the lighthouse and create reactive patterns depending on the wave height and proximity of the ferry that docks there.

This seems to be an evolving project, with more features being added slowly over time. We love the idea of searching for the WiFi access point on the ferry to tell when it’s coming in to port, and the wave height sensor should also prove interesting data, with trends at the low-frequency tidal rate as well as higher frequency single waves that come in every few seconds. What other inputs are available? How many are too many?

It’s so cool that a group of tech-minded art hackers could get access to a big building like this. Great job, [Jan] and [Rasmus] and [everyone else]!

Continue reading “Horten Fyr Is Norwegian For Blinkie” →

Open Your Garage Door With Your Smartphone

January 31, 2017 by James Hobson 42 Comments

The eternal enemy of [James Puderer]’s pockets is anything that isn’t his smartphone. When the apartment building he resides in added a garage door, the forces of evil gained another ally in the form of a garage door opener. So, he dealt with the insult by rigging up a Raspberry Pi to act as a relay between the opener and his phone.

The crux of the setup is Firebase Cloud Messaging (FCM) — a Google service that allows messages to be sent to devices that generally have dynamic IP addresses, as well as the capacity to send messages upstream, in this case from [Puderer]’s cell phone to his Raspberry Pi. After whipping up an app — functionally a button widget — that sends the command to open the door over FCM, he set up the Pi in a storage locker near the garage door and was able to fish a cable with both ethernet and power to it. A script running on the Pi triggers the garage door opener when it receives the FCM message and — presto — open sesame.

Continue reading “Open Your Garage Door With Your Smartphone” →

An Awesome Interactive LED Table

January 31, 2017 by Jenny List 40 Comments

If you want to create a large display with a matrix of LEDs, it’s a relatively straightforward process. Thanks to addressable LED tape and microcontrollers it becomes more of a software issue than one of hardware. [Vincent Deconinck] had some inexpensive WS2812 strips, so he sliced into an inexpensive IKEA coffee table and mounted them in a grid beneath an acrylic sheet. Some work with Arduino Nanos and a Raspberry Pi later, and he had a very acceptable LED matrix table.

An attractive hack, you might say, and leave it at that. But he wasn’t satisfied enough to leave it there, and so to make something rather special he decided to add interactivity. With an infra-red emitter and receiver as part of each pixel, he was able to turn an LED table into an LED touchscreen, though to be slightly pedantic it’s not sensing touch as such.

The design of the IR sensors was not entirely straightforward though, because to ensure reliable detection and avoid illumination from the LED they had to be carefully mounted and enclosed in a tube. He also goes into some detail on the multiplexing circuitry he used to drive the whole array from more Arduinos and a GPIO expander.

The write-up for this project is a long one, but it’s well worth the read as the result is very impressive. There are several videos but we’ll show you the final one, the table playing touch screen Tetris.

Continue reading “An Awesome Interactive LED Table” →

Cheap DIY FPV Micro-Drone

January 31, 2017 by James Hobson 28 Comments

FPV drones are a fun but often costly hobby for beginners. Opting for a smaller drone will reduce the chance of damaging the drone when one invariably crashes and the smaller props are also a lot safer if there are any innocent bystanders. YouTuber and Instructables user [Constructed] wanted a cheap FPV capable drone that they could comfortably fly in-and-out of doors, so of course they built their own.

Once the drone’s frame was 3D printed, the most complex part about soldering four small-yet-powerful 8.5 mm motors to the Micro Scisky control board is ensuring that you attach them in the correct configuration and triple-checking them. A quick reshuffling of the battery connections and mounting the FPV camera all but completed the hardware side of the build.

Before plugging your flight controller into your PC to program, [Constructed] warns that the battery must be disconnected unless you want to fry your board. Otherwise, flashing the board and programming it simply requires patience and a lot of saving your work. Once that’s done and you’ve paired everything together, the sky — or ceiling — is the limit!

Continue reading “Cheap DIY FPV Micro-Drone” →

Awesome Prank Or Circuit-Breaker Tester?

January 31, 2017 by Elliot Williams 54 Comments

Many tools can be used either for good or for evil — it just depends on the person flipping the switch. (And their current level of mischievousness.) We’re giving [Callan] the benefit of the doubt here and assuming that he built his remote-controlled Residual Current Device (RDC) tripper for the purpose of testing the safety of the wiring in his own home. On the other hand, he does mention using it to shut off all the power in his house during an “unrelated countdown at a party”. See? Good and evil.

An RCD (or GFCI in the States) is a kind of circuit breaker that trips when the amount of current in the hot and neutral mains power lines aren’t equal and opposite, which would suggest that the juice was leaking out somewhere, hopefully not through someone. They only take a few milliamps of imbalance to blow so that nobody gets hurt. Making a device to test an RCD is easy; a resistor between hot and the protective ground circuit would do.

[Callan] over-engineers. He used a 50 W resistor where 30 W would do under the worst circumstances. A stealthy solid-state relay switches the resistor in, driven by an Uno and a Bluetooth module, so he can trip his circuit breakers from his smartphone, naturally.
Continue reading “Awesome Prank Or Circuit-Breaker Tester?” →

ENIAC: The Way We Were

January 31, 2017 by Al Williams 33 Comments

When I first got interested in computers, it was all but impossible for an individual to own a computer outright. Even a “small” machine cost a fortune not to mention requiring specialized power, cooling, and maintenance. Then there started to be some rumblings of home computers (like the Mark 8 we recently saw a replica of) and the Altair 8800 burst on the scene. By today’s standards, these are hardly computers. Even an 8-bit Arduino can outperform these old machines.

As much disparity as there is between an Altair 8800 and a modern personal computer, looking even further back is fascinating. The differences between the original computers from the 1940s and anything even remotely “modern” like an Altair or a PC are astounding. If you are interested in that kind of history, you should read a paper entitled “Electronic Computing Circuits of the ENIAC” by [Arthur W. Burks].

These mid-century designers used tubes and were blazing new ground. Part of what makes the ENIAC so different is that it had a different design principle than a modern computer. It was less a general purpose stored-program computer and more of a collection of logic circuits that could be configured to solve problems — sort of a giant vacuum tube FPGA, if you will. It used some internal representations that proved to be suboptimal which also makes it seem strange. The EDSAC — a later device — was closer to what we think of as a computer. Yet the ENIAC was a major step in the direction of a practical digital computer.

Cost and Size

The size of ENIAC is hard to imagine. The device had about 18,000 tubes, 7,000 diodes, 70,000 resistors, 10,000 capacitors, and 6,000 switches. There were ~~5 million hand-soldered joints~~! ([Thomas Haigh] tells us that while this is widely reported, the real number was about 500,000.) Physically, it stood 10 feet tall, 3 feet deep, and 100 feet long. The tube filaments alone required 80 kW of power. Even the cooling system consumed 20 kW. In total, it took 150 kW to run the beast.

The cost of the machine was about $487,000. Almost a half-million dollars in 1946 is plenty. But that’s nearly seven million dollars in today’s money. What was worth that kind of expenditure? The military built firing tables for shell trajectories. From the [Burks] paper:

“A skilled computer with a desk machine can compute a 60-second trajectory in about twenty hours…”

Keep in mind that in 1946, a computer was a person. [Burks] goes on to say that a differential analyzer can do the same job in 15 minutes. ENIAC, on the other hand, could do it in 30 seconds and with a greater precision than the differential analyzer.

Continue reading “ENIAC: The Way We Were” →