Listening To Mains Power

August 23, 2018 by Brian Benchoff 33 Comments

There’s a lot you can tell by looking at the waveform of your mains power. There are harmonics, transient changes, and periodic fluctuations that are correlated to the demand on the grid itself. Frequency shifts will tell you how fast or slow your clocks are running, and someone probably has a poorly isolated power line communication thing somewhere in your neighborhood. There’s a lot you can learn by looking at the waveform coming out of your outlets, but how do you tap into that? [David] is doing it with a PC sound card and some really interesting hardware.

The Grid 2 Audio module is [David]’s entry to this year’s Hackaday Prize, and it consists of three main parts. The first is the mechanical part of the design. This comes in the form of an IEC power socket with a built-in switch, fuse, and illumination. Of course, you could simply buy one of these, but [David] is teaching himself Autodesk Inventor, and you have to start somewhere. The second part of this build is the PCB power supply and mains input. This is basically a pair of transformers, a PCB, and a whole lot of isolation to make this a safe board. The third part is a signal conditioning board that sends the waveform to a 3.5mm jack, for easy processing with any audio capture hardware.

The hardest part of this board is, by far, the PCB design, and for that [David] went all out. There are some big, meaty traces on this thing and real separation between the high voltage and low voltage portions of the board. The end result is something that sends the mains waveform to an audio card for easy processing with MATLAB, and all the goodies that come from that.

The Square-Inch Project Rides Again!

August 7, 2018 by Elliot Williams 37 Comments

Want to play a game? Your challenge is to do something incredible with a printed circuit board that measures no more than one inch by one inch. It’s The Return of the One Square Inch Project and it’s going to be amazing!

We can’t believe that it’s been three years! The original One Square Inch Project was a contest dreamt up by Hackaday.io user [alpha_ninja] back in 2015, and we thought it was such a great idea that we ponied up some prizes. The entries were, frankly, the best we’ve ever seen. So we’re doing it again!

Last time around, the size constraint focused the minds and brought out the creativity in some of the best and brightest of Hackaday.io. What functionality or simply amusement can you pack into a square PCB that’s just a tad over 25 mm on a side? We’d like to see.

We’ll be featuring entries throughout the contest. We think geek ‘cred is the best reward but if you want something more to sweeten the pot here you go:

Grand Prize:
- $500 Cash!
Four Top Entries Win Tindie Gift Certificates:
- Best Project – $100
- Best Artistic PCB Design – $100
- Best Project Documentation – $100
- Best Social Media Picture or Video – $100
Five Runner-Up Entries:
- $100 OSH Park gift cards

Want some inspiration? Last time the winner was a quadcopter in one square inch, but there were tons of useful and amusing projects crammed into tight quarters, and many of them transcend their constraints. There were not one but two hi-fi sound cards: one for your laptop’s USB port and one for your microcontroller projects that is now officially supported by the Teensy Audio Library. Need a MPPT power converter for a small solar project? How about a plug-load meter that fits on a US mains plug or an I2C to WS2818 converter to make blinking easier?

There were breakout boards for nearly every imaginable chip, a radio downconverter from our own [Jenny List], and a great magnetic rotary encoder design. Key Pass, an Arduino in the size of a DIP-8, and of course a bat detector, a bubble display volt meter, a smart watch, and a capacitive touch wheel.

It’s been three years, and parts have gotten cheaper, smaller, and more capable. What’s newly feasible in a square inch that wasn’t way back in 2015? Show us what you got.

A Fully Open Source Raspberry Pi Synthesizer

June 8, 2018 by Tom Nardi 19 Comments

Have you ever seen something and instantly knew it was something you wanted, even though you weren’t aware it existed a few seconds ago? That’s how we felt when we received a tip about Zynthian, a fully open source (hardware and software) synthesizer. You can buy the kit online directly from the developers, or build your own from scratch using their documentation and source code. With a multitude of filters, effects, engines, and essentially unlimited upgrade potential, they’re calling it a “Swiss Army Knife of Synthesis”. We’re inclined to agree.

At the most basic level, the Zynthian is a Raspberry Pi 3 with a touch screen, a few rotary encoders, a dedicated sound card, and MIDI support. Software wise the biggest feature is arguably the real-time Linux kernel for the lowest latency possible. There’s also a custom web interface so you can control the Zynthian from another machine on the network if you want. As a matter of course, it also includes a wide array of pre-installed audio packages to experiment and create with.

Kits are offered at various prices from $420 USD for the top of the line model down to unpopulated PCBs for a few bucks. We like that they broke things down this way; allowing users of various skill (and or patience) to pay what they want. If you just want to buy the custom boards and roll your own case and Pi solution, you can do that.

If you want to go all in, you can build one entirely from scratch as well. Everything from the CAD files for the case to their custom rotary encoder library is completely open (most licensed under GPL v3) for anyone to use however they see fit. There’s even a page in the wiki for listing hardware which isn’t officially supported by the project, but remain as options for those looking to cut their own path.

Synthesizers are a fairly popular hacker project, from Google’s AI-powered version to single chip exercises in frugality. If you want to learn even more about the fine line between digital noise and music, check out this fantastic series by our very own [Elliot Williams].

[Thanks to Mynasru for the tip.]

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Vaporwave For The Parallel Port

June 7, 2018 by Brian Benchoff 35 Comments

FM synthesis is the sound of the 1980s, it’s the sound of shopping malls and Macintosh Plus. It’s the sound of the Motorola DynaTAC, busts of Helios, and the sound of ｖａｐｏｒｗａｖｅ　サ閲ユ. The chips most responsible for this sound is the OPL2 and OPL3, tiny little FM synthesizers on a chip, produced by Yamaha, and the core of the AdLib and Sound Blaster sound cards. It’s the chip behind the music in all those great DOS games.

Unfortunately, computers don’t have ISA slots anymore, and cards don’t work in 486 and Pentium-based laptops, the latest hotness for retrocomputing enthusiasts. For his Hackaday Prize entry, [serdef] is bringing the sound of the 80s to the parallel port with the OPL2LPT. It’s a sound card for the parallel port that isn’t just a resistor DAC like the Covox Speech Thing.

The design of the OPL2LPT is pretty much what you would expect; it’s an OPL2 chip, opamp, a 1/8″ jack, and a few passive components. The real trick here is in the driver; by default, every DOS game around expects an Adlib card on port 338h, whereas the parallel post is at 378h. A driver takes care of this in software, but it is possible to patch a game to change every write to an Adlib card to a write to a parallel port.

Already, [serdef]’s parallel port graphics card is a real, working product and has caught the attention of Lazy Game Reviews and the 8-Bit-Guy, you can check out those video reviews below.

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Windows For Workgroups 3.11 In 2018

May 15, 2018 by Eric Evenchick 61 Comments

It’s been 25 years since Microsoft released Windows for Workgroups 3.11. To take a trip back to the end of the 16-bit era of operating system, [Yeo Kheng Meng] got WFW 3.11 running on a modern Thinkpad.

To make things difficult, a few goals were set for the project. Obviously, this wouldn’t be much fun in a virtual machine, so those were banned. A video driver would be needed, since WFW 3.11 only supports resolutions up to 640×480 in software. Some basic support for sound would be desirable. Finally, TCP/IP networking is possible in WFW 3.11, so networking hardware would allow access modern internet.

[Yeo Kheng Meng] accomplished all of these goals on a 2009 Thinkpad T400 and throughly documented the process. Some interesting hacks were required, including the design of a custom parallel port sound card based on the Covox Speech Thing. Accessing HTTPS web servers required a man-in-the-middle attack to strip SSL, since the SSL support on WFW 3.11 is ancient and blocked by most web servers today.

If you want your own WFW 3.11 laptop, the detailed instructions will get you there. [Yeo Kheng Meng] has also provided the hardware design for the sound card. You can watch a talk on the process after the break.

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Portable DVD Player Gets Raspberry Pi Zero Upgrade

April 13, 2018 by Tom Nardi 24 Comments

You might remember a time when people thought portable DVD players were a pretty neat idea. In the days before netbooks, cheap tablets, and arguably even the widespread adoption of smartphones, it seemed perfectly reasonable to lug around a device that did nothing but play movies. Today we look back at them as we would flip phones: a quaint precursor to the technology overload we find ourselves in currently. But the fact remains that millions of these comical little devices were pumped into the greedy maw of the consumer electronics market. They’re ripe for the hacking, all you need is some inspiration.

So if this grafting of a portable DVD player and the Raspberry Pi Zero W created by [nutsacrilege] doesn’t get you sniffing around your local second-hand store for a donor device, nothing will. By integrating a Pi running Kodi, the player gets a multi-media kick in the pants that arguably makes up for the rather archaic form factor. Not only can it play a wide array of local and online content, but it could even be used as portable game system if you were so inclined.

Rest assured, this isn’t some lazy five-minute mod. All of the original physical controls have been made functional by way of a MCP3008 ADC connected to the Pi’s GPIO and some clever Python scripting. Even the headphone jack was made functional by wiring it up to a USB sound card, and by integrating a tiny stripped down hub he was also able to add an external USB port. Who needs discs when you can plug in a flash drive full of content?

Speaking of which, [nutsacrilege] reports that the original functions of the device are still intact after all his modifications. So if you can get the museum to loan you one, you can even play a DVD on the thing as its creators intended.

With luck, this project will help spur on some more portable DVD player hacking, which we’ve seen precious little of so far. Frankly, it would be nice to see people cramming Raspberry Pi’s into something other than Game Boys for once.

[via /r/raspberry_pi]