Necessity is the mother of invention, but sometimes frustration is as good a motivator. [Maciej] does a bunch of statistics in his day job using SPSS. Like most complicated pieces of software, it can get hung, and the only way to stop it is to manually kill the running processes. Apparently, that happened one time too many for [Maciej].
He took matters into his own hands, repurposing a big red emergency-stop button for the task. It’s mounted on a jar, and the microcontroller inside is configured as a USB keyboard. When he mashes the button, it opens the “Run…” menu and types out
taskkill spssengine.exe for him.
We can totally see the therapeutic value of such a device. Plus, in case SPSS is gobbling up his system memory and everything’s approaching standstill, the vital seconds saved by the microcontroller’s quick-typing fingers could be a lifesaver.
They’re a little hard to find in the US, but the ZX Spectrum is right up there with the Commodore 64 and the Atari 8-bit computers in England. [Alistair] wanted to recreate the feeling of sitting right in front of the TV with his Speccy, leading him to create the ZX Keyboard, a Spectrum repurposed into a USB keyboard.
While most projects that take an old key matrix and turn it into a USB keyboard use the TMK firmware, [Alistair] wanted to flex his programming muscles and wrote the firmware from scratch. It runs on an Arduino Pro Mini, scanning the matrix of five columns and eight half rows to turn combinations of keypresses into an astonishing number of commands, given the limited number of keys on the ZX.
The firmware is available on [Alistair]’s repo, available to anyone who doesn’t want to pay the £50 a new ZX Spectrum keyboard will cost. As far as the usability of a Spectrum keyboard goes, at least [Alistair] didn’t have an Atari 400 sitting in the attic.
If you are anything like [Antoine], you would love to be able to control your PC with a simple hand-held remote control from anywhere in your house. [Antoine] wrote in to tell us about his wireless computer remote that emulates a USB keyboard, making it suitable for any device that uses a USB keyboard.
His blog post is very well written and contains a ton of design information and background on the project. He initially wanting to easily control his PC’s music from anywhere in his house without needing to be within line of sight of his computer. The end result is a very handy remote that can be used to change music, video, and even launch applications on his computer. The system consists of a base station for his remote that connects to the computer and acts as a USB keyboard, and the remote itself. The base station uses V-USB on an Arduino to interface with the computer, and VirtualWire to handle the wireless protocol for the remote. For those of you who don’t know about VirtualWire (now superseded by RadioHead), it is a very cool Arduino library that lets you easily use raw wireless interfaces (also called vanilla wireless interfaces).
Without going into too much detail here (be sure to see the actual post for more information), the remote itself was redesigned after the initial proof of concept to maximize battery life. The final power consumption is very impressive, resulting in a battery life of more than two years! This remote system is very well put together and contains many aspects that can easily be reused for other projects.
Another week has gone by and we hope you’ve been happily hacking away in your underground lairs. If not, here’s some inspiration that didn’t quite make it to the front page this week:
[Razr] used a CFL ballast to replace the mechanical one in his fluorescent tube light fixture.
To make the drawers of his workbench more awesome [Rhys] used the faceplates from some servers.
This week saw some changes in the hobby PCB market. Looks like BatchPCB is being sold to OSH Park starting May 1st. [Thanks Brad]
[Rich Olson] shouldn’t have any trouble getting out of bed now that his alarm clock literally shreds cash if he doesn’t shut it off.
We faced the same problem as [Kremmel] when we first got a Raspberry Pi, no USB keyboard. We bought one but he simply hacked his laptop to work. [Thanks Roth]
You may remember that post about a self-propelled snowboard. Here’s a similar project that uses a screw-drive system.
And finally, if you need help reading a quadrature encoder from a microcontroller this lengthy technical post is the place to look.
If you’re a brooding author putting the finishing touches on the next Great American Novel™ while sipping a latte in Starbucks, a MacBook is far too common to impress uncultured proles guzzling caramel macchiatos. No, to impress the next [Joyce] or [T. S. Eliot] sitting at the table next to you, you’ll need something much more hip, like a kit to turn a typewriter into a USB keyboard.
This kit to turn an old Underwood into a USB keyboard comes from the drawing board of [Jack Zylkin], member of Philly hackerspace Hive 76. [Jack] managed to make the process of turning an old typewriter into a keyboard a relatively painless process.
[Jack] created a sensor board loaded up with 74HC595 shift registers that easily mounts to the frame of just about any typewriter. When a key on the typewriter is struck, the mechanical levers strike metal strips soldered to the sensor board. An ATMega microcontroller records these keypresses and sends them over a USB port just like any other USB keyboard.
Modifying a typewriter into a USB keyboard is one of those projects we’d dread; you’d think there would be far too much futzing about with a lot of small electrical contacts and dirty mechanical devices. [Jack] actually managed to put together a very nice kit to turn a typewriter into a keyboard here.
You can pick up a kit over at [Jack]’s etsy store, but doing the same thing with a bit of perf board isn’t out of the question. Awesome video after the break.
Continue reading “Typewriter is USB keyboard, also awesome”
When [beerninja] wanted to swap his USB keyboard from one game console to another without mucking about with wires, he asked the Hack A Day forums for some help. [Meseta] (AKA [UAirLtd]) came to the rescue and built [beerninja] a remote-controlled USB switch.
After opening up a no-name USB switch, [Meseta] discovered that the switching is done with simple relays and switches. A hugely overpowered Forebrain ARM dev board was used to pull each switch low for a few hundred milliseconds to switch the output USB port.
For the infrared remote control, [Meseta] dug into Lady Ada’s IR sensor tutorial and decoded buttons 1 through 4 on a Sky TV remote. Each button from one to four corresponds to the buttons on the USB sharing switch. The ‘0’ button was also decoded as a convenience to put the Forebrain into its reprogramming mode. After drilling a small hole for the IR receiver, the finished project was stuffed back into the original steel enclosure.
Check out the video of the switch in action after the break.
Continue reading “Remote-controlled USB switch”
Circuits@Home have managed to host a USB keyboard with an Arduino and display the keyboard inputs on a character LCD. This uses the USB host shield we covered in August. That host shield includes a MAX3421 which is used here to drive the character LCD.
The control code for the keyboard ends up being fairly simple. The keyboard is polled for entries. The HID input is then examined and converted to ASCII codes for use with the LCD screen. This could make for an excellent controller or debugger for embedded systems. The Arduino, shield, and LCD could be integrated into the keyboard itself with an I/O port for connecting to your project. Commands can be typed out and sent through the I/O port when enter is pressed, with feedback displayed on the screen.
The example code provided with this project lays out the framework for hosting peripherals. We’re looking forward to more projects, and code libraries that take advantage of this new functionality.