Vintage Keyboard Gets The QMK Treatment

June 19, 2020 by Tom Nardi 15 Comments

While nobody could deny that computing technology has some a long way in the last few decades, there are many out there who believe peak keyboard was sometime before the turn of the new millennium. They prefer the look, feel, and especially the sounds, of those classic keyboards to what passes for an input device these days. So much so that it’s not uncommon to see one of these old mammoths get freshened up and pushed into service with a modern computer.

Which is exactly what [Juan Pablo Kutianski] has done with his Compaq MX-11800. This keyboard, which is actually a branded version of the Cherry G80-11800, really stands out in a crowd. With an integrated trackball and a two-row arrangement for the function keys, it’s not hard to see why he’d want to show it off. But while the hardware itself was solid, the features and capabilities of this old school keyboard left something to be desired.

The solution was to replace the keyboard’s original electronics with a Teensy++2.0 running the popular QMK firmware. This not only made the keyboard USB, but allowed [Juan] to tweak things such as the trackball sensitivity and add in support for layers and macros. All of which can be managed through VIA, a graphical configuration tool for QMK.

As we’ve seen in so many projects, the combination of QMK running on the Teensy is a powerful tool for getting the most out of your keyboard. Whether breathing new life into a vintage piece of hardware or creating something truly custom like our very own [Kristina Panos] recently did, it’s definitely something to keep in mind if you’re considering any keyboard hacking.

ESP32 Becomes Music Player In Under 40 Lines Of Code

June 14, 2020 by Donald Papp 60 Comments

The demo code for [XTronical]’s ESP32-based SD card music player is not even 40 lines long, though it will also require a few economical parts before it all works. Nevertheless, making a microcontroller play MP3s (and other formats) from an SD card is considerably simpler today than it was years ago.

Part of what makes this all work is I2S (Inter-IC Sound), a format for communicating PCM audio data between devices. Besides the ESP32, at the heart of it all is an SD card reader breakout board and the MAX98357A, which can be thought of as a combination I2S decoder and Class D amplifier. The ESP32 reads audio files from the SD card and uses an I2S audio library to send the I2S data stream to the MAX98357A (or two of them for stereo.) From there it is decoded automatically and audio gets pumped though attached speakers.

A few economical components, and only a handful of connections between them.

It’s amazing how much easier audio is to work with when one can take advantage of shuffling audio data around digitally, and the decoder handles multiple formats with an amplifier built in. You can see [XTronical]’s ESP32 player in action in the video embedded below.

Continue reading “ESP32 Becomes Music Player In Under 40 Lines Of Code” →

Building An ESP32 Smart Power Strip From Scratch

June 10, 2020 by Tom Nardi 33 Comments

Surely the most straightforward way of creating a smart power strip would be to take an existing model and hack in some relays that you could fire with a WiFi-enabled microcontroller. But where’s the fun in that? Instead of repurposing a commercial power strip for his recent project, [Md Raz] decided to just build the whole thing himself.

The project started with a 3D printed enclosure that could hold the electronics and three panel mount sockets. The use of heat-set inserts makes it a bit more robust for future upgrade work, but otherwise it’s a fairly simple rectangular design. Nobody ever said a power strip had to be pretty, right? In addition to the panel mount sockets, there’s also a AC-DC converter to step mains voltage down to 5 VDC for the ESP32.

In addition to the microcontroller, the custom PCB in the power strip holds a trio of MOSFETs connected to AQH2223 solid state relay (SSR) chips. Once the ESP32 toggles the line attached to each MOSFET, the indicator LED above the outlet goes on and the appropriate SSR is thrown to turn on the power. With a simple web interface running on the microcontroller, all three outlets can be independently controlled from any device with a web browser.

If you’d like to limit your interaction with mains voltages, then we’ve seen some projects that commandeer the low-voltage side of a commercial smart power strip. But remember, putting a Raspberry Pi inside of a power strip might seem suspicious to some folks.

The Seedy World Of Message Serialization

June 10, 2020 by Kerry Scharfglass 26 Comments

Look, I’ve been there too. First the project just prints debug information for a human in nice descriptive strings that are easy to understand. Then some tool needs to log a sensor value so the simple debug messages gain structure. Now your debug messages {{look like : this}}. This is great until a second sensor is added that uses floats instead of ints. Now there are sprinklings of even more magic characters between the curly braces. A couple days later and things are starting to look Turing complete. At some point you look up and realize, “I need a messaging serialization strategy”. Well you’ve come to the right place! Continue reading “The Seedy World Of Message Serialization” →

STM32 Blue Pill Turned GPG Security Token

June 10, 2020 by Tom Nardi 30 Comments

Feeling the cost of commercial options like the YubiKey and Nitrokey were too high, [TheStaticTurtle] started researching DIY alternatives. He found an open source project allows the STM32F103 to act as a USB cryptographic token for GNU Privacy Guard, which was a start. All he had to do was build a suitable device to install it on.

The first step was to test the software out on the popular “Blue Pill” development board, which [TheStaticTurtle] documents in the write-up should anyone want to give it a try themselves. The ST-Link V2 was already a supported target, so it only took some relatively minor tweaks to get running and add support for a simple push button. The output of gpg --card-status showed the device was working as expected, so with the software sorted, it was time to take a closer look at the hardware.

To create his “TurtleAuth” dongle, [TheStaticTurtle] started with the basic layout of the Blue Pill and added in a TTP223E touch control IC. The original Micro USB port was also swapped for a male USB-A connector so the device could be plugged directly into a computer. An upper PCB, containing the status LEDs and touch pad, was then designed so it would fit over the main board as an enclosure of sorts. While the sides are still open, the device looks robust enough to handle life in a laptop bag at least.

While it’s not exactly a common project, this isn’t the first time we’ve seen somebody spin up their own hardware token. More evidence of what the dedicated individual can accomplish these days on a relatively limited budget.

An Open Hardware Modem For The Modern Era

June 9, 2020 by Tom Nardi 39 Comments

Readers of a certain age will no doubt remember the external modems that used to sit next to their computers, with the madly flashing LEDs and cacophony of familiar squeals announcing your impending connection to a realm of infinite possibilities. By comparison, connecting to the Internet these days is about as exciting as flicking on the kitchen light. Perhaps even less so.

But while we don’t use them to connect our devices to the Internet anymore, that doesn’t mean the analog modem is completely without its use. The OpenModem by [Mark Qvist] is an open hardware and software audio frequency-shift keying (AFSK) modem that recalls some of the charm (and connection speeds) of those early devices.

It’s intended primarily for packet radio communications, and as such is designed to tie into a radio’s Push-to-Talk functionality with a standard 3.5 mm jack connector. Support for AES-128 encryption means it will take a bit more than an RTL-SDR to eavesdrop on your communications. Though if you’re really worried about others listening in, the project page says you could even use the OpenModem over a wired connection as you would have in the old days.

If you just want a simple and reliable way to get a secure AFSK communication link going, the OpenModem looks like it would be a great choice. But more than that, it offers a compelling platform for learning and experimentation. The hardware is compatible with the Arduino IDE, so you can even write your own firmware should you want to spin up your own take on this classic communications device.

The OpenModem is the evolution of the MicroModem that [Mark] developed years ago, and it’s clear that the project has come a long way since then. Of course, if you’re more about the look than the underlying technology, you could always just put a WiFi access point into the case of an old analog modem.

[Thanks to Boofdas for the tip.]

Run Your Favorite 8-bit Games On An ESP32

June 9, 2020 by Kerry Scharfglass 20 Comments

Here at Hackaday HQ we’re no strangers to vintage game emulation. New versions of old consoles and arcade cabinets frequently make excellent fodder for clever hacks to cram as much functionality as possible into tiny modern microcontrollers. We’ve covered [rossumur]’s hacks before, but the ESP_8-bit is a milestone in comprehensive capability. This time, he’s topped himself.

There isn’t much the ESP 8-bit won’t do. It can emulate three popular consoles, complete with ROM selection menus (with menu bloops). Don’t worry about building a controller, just connect any old (HID compliant) Bluetooth Classic keyboard or WiiMote you have at hand. Or if that doesn’t do it, a selection of IR devices ranging from joysticks from the Atari Flashback 4 to Apple TV remotes are compatible. Connect analog audio and composite video and the device is ready to go.

The system provides this impressive capability with an absolute minimum of components. Often a schematic is too complex to fit into a short post, but we’ll reproduce this one here to give you a sense for what we’re talking about. Come back when you’ve refreshed your Art of Electronics and have a complete understanding of the hardware at work. We never cease to be amazed at the amount of capability available in modern “hobbyist” components. With such a short BOM this thing can be put together by anyone with an ESP-32-anything.

There’s one more hack worth noting; the clever way [rossumur] gets full color NTSC composite video from a very busy microcontroller. They note that NTSC can be finicky and requires an extremely stable high speed reference clock as a foundation. [rossumur] discovered that the ESP-32 includes a PLL designed for audio work (the “APLL”) which conveniently supports fractional components, allowing it to be trimmed to within an inch of the desired frequency. The full description is included in the GitHub page for the project and includes detailed background of various efforts to get color NTSC video (including the names of a couple hackers you might recognize from these pages).

Continue reading “Run Your Favorite 8-bit Games On An ESP32” →