Human input devices are a consumable on our computers today. They are so cheap and standardised, that when a mouse or a keyboard expires we don’t think twice, just throw it away and buy another one. It’ll work for sure with whatever computer we have, and we can keep on without pause.
On earlier machines though, we might not be so lucky. The first generation of computers with mice didn’t have USB or even PS/2 or serial, instead they had a wide variety of proprietary mouse interfaces that usually carried the quadrature signals direct from the peripheral’s rotary sensors. If you have a quadrature mouse that dies then you’re in trouble, because you won’t easily find a new one.
Fortunately there is a solution. In the intervening decades the price of computing power has fallen to the extent that you can buy a single board computer with far more than enough power to interface with a standard USB mouse and emulate a quadrature mouse all at the same time. This was exactly the solution [Andrew Armstrong] took to provide a replacement mouse for his Atari ST, he used a Raspberry Pi as both USB host and quadrature mouse emulator (YouTube link) through its GPIOs.
There aren’t too many sports named for the sound that is produced during the game. Even though it’s properly referred to as “table tennis” by serious practitioners, ping pong is probably the most obvious. To that end, [Nekojiru] built a ping pong ball juggling robot that used those very acoustics to pinpoint the location of the ball in relation to the robot. Not satisfied with his efforts there, he moved onto a visual solution and built a new juggling rig that uses computer vision instead of sound to keep a ping pong ball aloft.
The main controller is a Raspberry Pi 2 with a Pi camera module attached. After some mishaps with the planned IR vision system, [Nekojiru] decided to use green light to illuminate the ball. He notes that OpenCV probably wouldn’t have worked for him because it’s not fast enough for the 90 fps that’s required to bounce the ping pong ball. After looking at the incoming data from this system, an algorithm extracts 3D information about the ball and directs the paddle to strike the ball in a particular way.
If you’ve ever wanted to get into real-time object tracking, this is a great project to look over. The control system is well polished and the robot itself looks almost professionally made. Maybe it’s possible to build something similar to test [Nekojiru]’s hypothesis that OpenCV isn’t fast enough for this. If you want to get started in that realm of object tracking, there are some great projects that make use of that piece of software as well.
Death Stars were destroyed twice in the Star Wars movies and yet one still lives on in this 168 LED persistence of vision globe made by an MEng group at the University of Leeds in the UK. While Death Stars are in high demand, they mounted it on an axis tilted 23.4° (the same as the Earth) so that they can show the Earth overlaid with weather information, the ISS position, or a world clock.
More details are available on their system overview page but briefly: rotating inside and mounted on the axis is a Raspberry Pi sending either video or still images through its HDMI port to a custom made FPGA-based HDMI decoder board. That board then controls 14 LED driver boards mounted on a well-balanced aluminum ring. All that requires 75W which is passed through a four-phase commutator. Rotation speed is 300 RPM with a frame rate of 10 FPS and as you can see in the videos below, it works quite well.
In the almost five years since the launch of the original Raspberry Pi we have seen a huge array of competitors emerge in the inexpensive single board computer market. Many have created their own form factors, but an increasing number have gone straight for the jugular of the fruity board from Cambridge by copying its form factor and interfaces as closely as possible. We’ve seen sterling efforts from the likes of Banana Pi, Odroid, and several others, but none have yet succeeded in toppling it from its pedestal.
The latest contender in this arena might just make more of an impact though, because it comes from a major manufacturer, a name you will have heard of. Asus have quietly released their Tinker, board that follows the Pi form factor very closely, and packs a 1.8 GHz quad-core ARM Cortex A17 alongside an impressive spec we’ve captured as an image for this article. Though they are reticent about it on their website, there is a SlideShare presentation with some of the details, which we’ve placed below the break.
At £55 (about $68) where this is being written it’s more expensive than the Pi, but Asus go to great lengths to demonstrate that it is significantly faster. We will no doubt verify the accuracy of that claim as the boards find their way into the hands of our community. Still, it features a mostly-Pi-compatible I/O header, and the same display and camera connectors as the Pi. There is no information as to how compatible these last two are though.
Other boards in this arena have boasted impressive hardware, but have fallen down when it comes to the support for their operating systems. When you buy a Raspberry Pi it is not just the hardware you are taking on but the Raspbian operating system and its impressive community support. The Tinker supports Debian, so if Asus is to make a mark they must ensure that its support rivals that of the board it is targeting. If they succeed in that endeavor then the result can only be good news for us.
There are several open source phones out there these days, but all of them have a downside. Hard to obtain parts, hard to solder, or difficult programming systems abound. [Arsenijs] is looking to change all that with ZeroPhone. ZeroPhone is based upon the popular Raspberry Pi Zero. The $5 price tag of the CPU module means that you can build this entire phone for around $50 USD.
The radio module in the ZeroPhone is the well known SIM800L 2G module. 2G is going away or gone in many places, so [Arsenijs] is already researching more modern devices. An ESP8266 serves as the WiFi module with an OLED screen and code in python round out this phone. Sure, it’s not a fancy graphical touchscreen, but a full desktop is just a matter of connecting a display, mouse, and keyboard.
For the security conscious, the ZeroPhone provides a unique level of control. Since this is a Raspberry Pi running Linux, you choose which modules are included in the kernel, and which software is loaded in the filesystem. And with news that we may soon have a blobless Pi, the firmware hiding in the radio modules are the only black boxes still remaining.
What to call this LED strip music visualizer is a puzzler. It lights up and pulsates in time with music similar to the light organs of 1970s psychedelia fame, but it’s more than that. Is it more like the Larson Scanner that graced the front of [David Hasselhoff]’s ride on Knight Rider? A little, but not quite.
Whatever you decide to call this thing, it looks pretty cool, and [Scott Lawson] provides not one but two ways to build it. The business end is a simple strip of WS2812b addressable LEDs. It looks like the first incarnation of the project had an ESP8266 driving the LEDs in response to commands sent to it from a PC running the visualization code, written in Python. That setup keeps the computationally intensive visualization code separate from the display, but limits the display to 256 pixels and probably has to deal with network latency. The Raspberry Pi version both crunches the numbers and drives the display, but the Pi doesn’t have the oomph to run both the LEDs and the GUI, which is pretty interesting to look at by itself. The video below shows the different visualization modes available — we’re partial to the “energy effect” at the end.
Take your pick of hardware and throw a couple of these things together for your next rave. And if you need a little more background on the aforementioned Larson Scanner, we’ve got you covered.
It’s obvious this was a controversial product, and maybe the Hackaday verdict had been a little summary based on the hammer aspect of the story. So to get further into what all the fuss had been about I ordered a Pi Zero and the solderless pin kit to try for ourselves.