Bringing Guitar Synthesis To The Microcontroller

April 10, 2018 by Brian Benchoff 12 Comments

If you’re working with audio in an embedded environment, the best option for years now has been the Teensy 3 microcontroller board. This choice has mostly been due to its incredible power and audio libraries, but until now we really haven’t seen a stompbox-style interface that used the Teensy to its fullest extent. Now we have, in [Wolkstein]’s GitSynth, everything you could want in a synthesizer that processes the signals from an electric guitar.

The core of this build is a Teensy 3, and all the audio goodies that come with that. Also included is a USB MIDI and audio interface, smartly both attached to a panel-mount USB-B connector on the back of the stompbox. Other controls include a single mono in jack for guitars and synths, two mono out jacks for stereo-ish output, a bunch of footswitches for bypass, tap tempo, preset selection, a jack for an expression pedal, and some buttons to move around the LCD user interface.

While putting a powerful microcontroller in a stomp box for is a project we’ve seen many times, this project really shines with the MIDI GUI that’s built for a device with a real display and a mouse. [Wolkstein] built a PyQt-based app for this synth, and it’s a plethora of buttons and sliders that looks similar enough to a real synthesizer. There’s enough configurability here for anyone.

You can check out the demo video (in German, but auto-translate subtitles exist) below.

Thanks [Mynaru] for the tip!

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Recharging Drones On The Go With A Supercharger

April 10, 2018 by Brian Benchoff 45 Comments

If Techcrunch is to be believed, our skies will soon be filled with delivery robots, ferrying tacos and Chinese food and Amazon purchases from neighborhood-area dispatch stations to your front door. All of this is predicated on the ability of quadcopters to rapidly recharge their batteries, or at the very least swap out batteries automatically.

For their Hackaday Prize entry, [frasanz], [ferminduaso], and [david canas] are building the infrastructure that will make delivery drones possible. It’s a drone supercharger, or a robot that grabs a drone, swaps out the battery, and sends it off to deliver whatever is in its cargo compartment.

This build is a droneport of sorts, designed to have a drone land on it, have a few stepper motors and movable arms spring into action, and replace the battery with a quick-change mechanism. This can be significantly more difficult than it sounds — you need to grab the drone and replace the battery, something that’s easy for human eyes and hands, but much harder for a few sensors and aluminum extrusion.

To change batteries, the team is just letting the drone land somewhere on a platform that’s a few feet square. Arms then move it, pushing the drone to the center, and a second arm then moves in to swap the battery. The team is using an interesting locking cam solution to clamp the battery to the drone. It’s much easier for a machine to connect than the standard XT-60 connector found on race quads.

Is this the project the world needs? Quite possibly so. Drones are going to be awesome once battery life improves. Until then, we’ll have to live with limited flight times and drone superchargers.

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Hackaday Links: April 8, 2018

April 8, 2018 by Brian Benchoff 7 Comments

SiFive raised $50 Million in funding. SiFive is a semiconductor working on two fronts: they want to democratize silicon prototyping, and they’re the people making the HiFive series of microcontrollers and SoCs. The HiFives are built on the RISC-V instruction set, a Big-O Open instruction set for everything from tiny microcontrollers to server CPUs. With RISC-V, you’re not tied to licensing from ARM or their ilk. Recently SiFive introduced an SoC capable of running Linux, and the HiFive 1 is a very fast, very capable microcontroller that’s making inroads with Nvidia and Western Digital. The new round of funding is great news for anyone who wants Open Source hardware, and the silicon prototyping aspect of it is exceptionally interesting. Great news for SiFive.

Guess what’s in just a few weekends? The Vintage Computer Festival Southeast. The VCFSE is Hotlanta’s own vintage computer festival, with a whole host of speakers, exhibits, and consignment to tickle those vintage dopamine receptors. On deck for the speakers is [Michael Tomczyk], one of the people responsible for the VIC-20, and [Scott Adams], no the other [Scott Adams], creator of adventure-style games for personal computers but not that adventure-style game. The exhibits will include Japanese retro computers, simulating an ENIAC and a mechanical keyboard meetup. If you’re around Georgia, this is an event worth attending.

Conference season is just around the corner, and you know what that means. It’s time to start ramping up for #badgelife. What is badgelife? It’s a hardware demoscene of electronic conference badges. This year, the badgelife scene has stumbled upon something everyone can get in on. Add-ons! They’re electronic hats (or shields, or capes) for all the badges. Physically, it’s a 2×2 pin header. Electronically, it’s power, ground and I2C. Want to prototype your own add-on? Good news, there’s a development board.

The Titius-Bode law states the semi-major axes of planets follow a geometric progression. The (simplified, incorrect) demonstration of this law states Mercury orbits at 0.25 AU, Venus at 0.5 AU, Earth at 1 AU, Mars at 2 AU, and continues to the outer planets. The Titius-Bode law is heavily discredited in the planetary science community, and any paper, talk, or manuscript is rejected by scientific editors out of hand. The Titius-Bode law is the planetary science equivalent of flat Earth conspiracy theories and Nazi moon bases; giving any consideration to the idea confirms you’re a moron. This week, some consulting firm posted something that is the Titius-Bode law on their blog. Why? So it could be submitted to Hacker News for that sweet SEO. This submission was upvoted to the top position, and is a wonderful springboard to argue an interesting point on media literacy. I posit the rise of news aggregators (facebook, twitter, digg, reddit, and HN), is the driving force behind ‘fake news’ as lay people become the gatekeepers. Prove me wrong.

The Department of Homeland Security has confirmed there are cell-site simulators (Stingrays, IMSI-catchers, or otherwise known as your own private cell phone base station) around Washington DC. It’s unknown who is operating these simulators, or even where they are. There are two things to read between the lines with this information: Duh, there are rogue Stingrays in DC. Holy crap duh. I bet there are also some around midtown Manhattan. You can buy the stuff to do this on eBay. Personally, I’ve found half a dozen Stingrays or other rogue cell stations this year (guess where?). Second, why is this a news item now? Is this a signal that the DHS will start clamping down on stuff you can buy on eBay? Hop to it, people; cellular hardware is a great way to make a liquid nitrogen generator.

New App Note Day: Internet Of Pillows

April 8, 2018 by Brian Benchoff 25 Comments

The Internet of Things is a cancer that consumes all reasonable expectations of technology, opens vast security holes we’ve never had to deal with before, and complicates life in the pursuit of quarterly gains from whatever technology startup is hot right now. We are getting some interesting tech out of it, though. The latest in the current round of ‘I can’t believe someone would build that’ is the Internet of Pillows. No, it’s not a product, it’s just an application note, but it does allow us to laugh at the Internet of Things while simultaneously learning about some really cool chips.

The idea behind this ‘smart’ pillow is to serve as a snoring sensor. When the smart pillow detects the user is snoring, a small vibration motor turns on to wake up the user. There’s no connectivity in this smart pillow, so the design is relatively straightforward. You need a microphone or some sort of audio sensor, you should probably have a force-sensitive resistor so you know the pillow is actually being used, and you need a vibration motor. Throw in a battery for good measure. Aside from that, you’re also going to need a microcontroller, and that’s where things get interesting.

This application note was written as a demonstration of what Dialog’s GreenPAC devices can do. We’ve seen these things before, and the idea behind these devices is something like a ‘modern-day PAL’ or ‘a really, really limited FPGA’. It’s a bit more than that, though, because the GreenPAC devices are mixed-signal, there are some counters and latches in there, and all the programming is done through a graphical IDE. If you need a small, low-power chip that only does one thing, the GreenPAC is right up your alley.

So, how does this device detect snoring? The code pulls data from the sound sensor every 30 ms, with a 5 ms time window. If this sound repeats again within six seconds, it’s assumed the user is snoring. The logic then turns on the vibration motor, greatly annoying whoever is sleeping. All of this is done through a graphical IDE, which I’m sure will draw the ire of some, but there really aren’t that many pins or that many LUTs on GreenPAC devices, so it’s never going to get too out of hand.

The GreenPAC is a very interesting family of parts that we don’t see too much of around here. That’s a shame, because for low-power applications that don’t need a lot of horsepower, the GreenPAC seems like it would be very useful. Slightly more useful than an Internet of Things pillow, at least.

You Can Build Anything Out Of What Is Holding Your 97 Eagle Talon Together

April 7, 2018 by Brian Benchoff 29 Comments

We all know it, we all love it, and the guy parked outside of the 7-11 covered his car in it. What is it? Polyester body filler, better known by the almost generic trademark, Bondo. There’s a lot more you can do with Bondo than fairing in that sweet body kit, bro, and [Eric Strebel] is here to show you how far you can push the mechanical properties of polyester body filler.

We didn’t always have polyester body filler. In the days before OSHA, auto body workers would use a torch, bricks of lead, and a grinder. You can check out a video of the era before OSHA here. Needless to say, vaporizing and grinding lead in your shop isn’t the greatest idea, and there had to be a better way. This led Robert ‘Bondo Bob’ Spink to invent a much less toxic auto body filler that we now know as Bondo.

For the beginning of the demonstration, [Eric] mixes up a cup of polyester body filler with a few special additions: he’s using printer ink to get his mixture to something other than that one shade of pink we all know. Although Bondo is a bit too thick to cast, he did manage to put a little bit of it in a square mold, a PVC pipe, and applied a little to foam and wood. It’s enough for a demonstration, but for the actual ins and outs of machining Bondo we’re going to have to wait until [Eric]’s next video. Until then, you can check out this introduction below, or look at his previous work on free-form sculpting of uncured Bondo.

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The Better RetroPie Handheld

April 7, 2018 by Brian Benchoff 15 Comments

The Raspberry Pi has become the best video game console on the planet. With RetroPi, anyone can play Super Mario 3, Doctor Mario, and even Doki Doki Panic. Adafruit’s PiGRRL Zero and [Wermy]’s reconfabulation of an old brick Game Boy to house a Raspi Zero and display have made the Raspberry Pi portable, along with all those retro games we love so dearly.

There’s a problem with these builds, though. They only use the Raspberry Pi Zero, and with that the limitations on emulation performance, and the Raspi 3 is far too big for a portable console. What’s the solution? It’s the greatest homebrew console ever created. For this year’s Hackaday Prize, [DeanChu] is building the Retro-CM3. It’s a retro handheld with a 3D printed enclosure, that’s powered by the Raspberry Pi Compute Module 3. Stand back, folks. We have a winner that will top the Raspberry Pi and 3D printing subreddits.

The key feature for this build is, of course, the raw processing power of the Raspberry Pi Compute Module 3. This is a Raspberry Pi 3 with 4 GB of eMMC stuffed onto a board that fits into an SODIMM socket. The pins on this device give you access to the GPIOs and the DSI connector. All you really need to turn this into an amazing vintage emulation console is a breakout board with a few buttons, power supply, and a display.

The extra components for this build include a 3.2 inch LCD using the DPI interface. There’s a speaker, and a 2000mAh battery. The real tricky part here is the custom PCB, breaking out the DPI pins on the Compute Module, adding a small speaker, and throwing a small STM32 to read the buttons. It’s an entire system, ready to be housed in a 3D printed enclosure.

This is, simply, the best Raspberry Pi portable you’ll ever see, at least until we get a Rasberry Pi Zero with the capabilities of the Pi 3. It’s an excellent use of the very small Compute Module, and one of the most polished Hackaday Prize entries we’ve seen thus far.

Because Building A Relay Computer Isn’t Hard Enough

April 6, 2018 by Brian Benchoff 28 Comments

For this year’s Hackaday Prize, we’re doing something special. We’re introducing achievements for Prize projects. Think of them as merit badges. If your Hackaday Prize project has multiple parts that come together into one unified, awesome whole, you get the Voltron achievement. If you’ve built a musical instrument that unexpectedly blows everyone’s minds, you get the Diva Plavalaguna Achievement. A select few entries will earn the Pickle Rick achievement. What’s this? It’s a jaw-dropping build that makes you shake your head in the totality of engineering perfection.

Here’s a project that nails this achievement. It’s a homebrew computer, made out of relays, that runs a custom instruction set. It’s built on Brainf*ck. It is, by far, the most absurd and amazing homebrew computer you’ve ever seen.

First, the hardware. This CPU is built out of about 800 Soviet reed relays, RES64, RES55, and RES-43 relays, if you want some part numbers. These relays are mounted on logic cards connected to a backplane. Each backplane consists of thirty-two of these cards, and it takes two backplanes to build up a 16-bit full adder. The 16-bit instruction pointer and 16-bit address pointer each fit on half a backplane.

Moving up one level, the instruction set for this computer is based on Brainf*ck, with a few additions. The ‘+’ instruction adds to the current value, the ‘>’ instruction still increases the current memory address, but there are a few new instructions that make this CPU not an interminable world of suffering. There’s now a ‘write current data value to register’ commands, and logical XOR instructions.

Have relay-based computers been done before? Yes, and so have Brainf*ck ISAs. The combination is rarely seen, and we’ve never seen one that performs this well. Below, you can see a video of this computer counting at 500 operations per second (or 500 Hz from a frequency counter). This is really unimaginable with any other relay computer we’ve seen, and it’s all thanks to those really tiny Soviet tubes. If you want a Hackaday Prize project that’s jaw-dropping, here you go.

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