Some people like to tweak cars. Some like to overclock PCs. Then there are the guys like [Jack Zimmermann] who are obsessed with accurate time. He’s working on a project that will deploy NTP (Network Time Protocol) servers in different African countries and needed small, cheap, energy-efficient, and accurate servers. What he wound up with is a very accurate setup for around $200. Along the way, he built some custom hardware, and hacked a computer to sync to the GPS clock reference.
His original attempt was with a Raspberry Pi 3. However, the network adapter isn’t the fastest possible, both because it is 100 MBPS and, primarily, because it is connected via the USB bus. Network latency due to these limitations makes it difficult to serve accurate time.
His solution includes an Odroid C2. For $50 it is a very capable computer with four cores, gigabit Ethernet, and can even use eMMC storage which is faster than the usual SD card. You can still use a conventional SD card, though, if you prefer.
We have no idea if the background story is true or not, but we’re not going to let something like “truth” get in the way of a good story. The way [Kwan3217] tells it, first there were hours on sundials. Then when these were divided into sixty minute sections, they were called “minutes”. “Seconds” comes from a second division by sixty, into “second minutes”. The “third” division into sixty would give a time unit that lasts a sixtieth of a second.
It’s impossible to know when society began to manicure its front lawns. Truth be told — cutting the grass was, and still is a necessity. But keeping the weeds at bay, trimming, edging and so forth is not. Having a nice lawn has become a status symbol of modern suburbia all across the globe. When the aliens arrive, one of the first things they will surely notice is how nice our front lawns are. This feature of our civilization could have only been made possible with the advent of specialized grass-cutting machines.
It could be argued that the very first lawnmowers were live stock. The problem was they were quite high maintenance devices and tended to provide a very uneven cut, which did not bode well for families striving for the nicest front lawn on the dirt road. Coupled with the foul odor of their byproducts, the animals became quite unpopular and were gradually moved out of site into the back yards. Other solutions were sought to maintain the prestigious front yard.
The first mechanical lawnmower was invented in 1830 by a man named Edwin Budding, no doubt in an effort to one-up his neighbor, who still employed a Scythe. Budding’s mower looked much like today’s classic reel mowers, where a rotating cylinder houses the blades and rotates as the mower is pushed forward. Budding was granted a patent for his device by England, much to the dismay of his fellow neighbors — most of whom were forced to buy Budding’s mower due to the fact that everyone else in the neighborhood bought one, even though they weren’t actually needed.
By the early 1930’s, the cold war started by Budding and his neighbor had spread to almost every front yard on earth, with no end in sight. Fast forward to the modern era and the lawn and garden market did 10 billion in sales in 2014 alone. Technological advances have given rise to highly advanced grass-munching machines. For smaller yards, most use push mowers powered by a single cylinder IC engine. Many come with cloth bags to collect the clippings, even though everyone secretly hates using them because they gradually fill and make the mower heavier and therefore more difficult to push. But our neighbors use them, so we have to too. Larger yards require expensive riding mowers, many of which boast hydrostatic transmissions, which owners eagerly brag about at neighborhood get-togethers, even though they haven’t the slightest clue of what it actually is.
Us hackers are no different. We have front lawns just like everyone else. But unlike everyone else (including our neighbors) we have soldering irons. And we know how to use them. I propose we take a shot-across-the-bow and disrupt the neighborhood lawn war the same way Budding did 85 years ago. So break out your favorite microcontroller and let’s get to work!
The Subaru BRZ (also produced for Toyota as the GT86) is a snappy sportster but [megahercas6]’s old US version had many navigation and entertainment system features which weren’t useful or wouldn’t work in his native Lithuania. He could have swapped out the built in screen for a large 4G Android tablet/phone, but there’s limited adventure in that. Instead, he went ahead and built his own homemade Navigation system by designing and integrating a whole bunch of hardware modules resulting in one “hack” of an upgrade.
The system is built around a Lenovo 4G phone-tablet running android and supporting GPS, GLONASS as well as the Chinese BeiDou satellite navigation systems. He removed the original daughter board handling the USB OTG connection on the tablet, and replaced it with his version so he could connect it to his external USB board via a flat ribbon cable. The USB board contains a Cypress 4-port USB hub. One port is used as the USB HID device to allow external buttons for system control — Power, Volume Up/Down, Fwd/Rev, Play/Pause, and Phone Answer/Hangup. The second port is used as a regular USB input to allow connecting external devices such as flash drives. The third one goes to a reversing camera while the fourth port goes to a USB DAC.
The USB DAC is another hardware board by itself and also includes a Bluetooth module which integrates his phone’s audio and control functions with the on-board system. There’s also an audio mixer which allows him to use the phone audio without having to miss out on the navigation prompts from the tablet. Both boards also contain several peripheral circuits such as amplifiers and DC power supplies. Audio to the speakers is routed through six LM3886 based power amplifier boards. And the GPS module receives its own special low-noise amplifier board to ensure extremely strong reception at all times. That’s a total of ten boards custom built for this project. He’s also managed to source all the original harness connectors so his system is literally a snap in replacement. The final assembly looks pretty dashing.
For some strange reason, the Lenovo tablet uses 4.35V as the ‘fully charged” value for its LiPo instead of the more common 4.20V, so even with the whole system connected to a hefty 12V lead acid battery from which he’s deriving the 4.20V charging voltage for the tablet, it still complains about “low battery” — and he’s looking for advice on how he can resolve that issue short of blowing up the LiPo by using the higher charge voltage. Besides that, he’s (obviously a kickass) hardware designer and a little bit rusty on the software and programming side of things, for which he’s looking for inputs from the community. His introductory video is almost 30 minutes long, but the shorter demo video after the break shows the system after installation in his car. He’s posted all of his Altium hardware source files on the project page, but until he shares PDF versions, it would be difficult for most of us to look at his work.
A lot of people around here got their start in electronics with guitar pedals. This means soldering crappy old transistors to crappy old diodes and fawning over your tonez, d00d. Prototyping guitar pedals isn’t easy, though, and now there’s a CrowdSupply project to make it easier The FX Development Board is just that — a few 1/4″ jacks, knobs, pots, power supply, and a gigantic footswitch to make prototyping guitar pedals and other musical paraphernalia easy. Think of it as a much more feature-packed Beavis Board that’s still significantly cheaper.
How do Communicators in Star Trek work? Nobody knows. Why don’t the crew always have to tap their badge before using it? Nobody knows. How can the com badge hear, ‘Geordi to Worf’, and have Worf instantly respond? Oh, we’ve argued about this on IRC for years now. Over on Hackaday.io, [Joe] is building a Star Trek com badge. The electronics are certainly possible with modern microcontrollers, but for the enclosure, we’ll have to review a few scenes from Time’s Arrow and The Enemy.
[Alois] was working with an Intel Edison on a breadboard. He was generating a signal, and sending it through a little tiny breadboard wire to an oscilloscope. The expected waveform should have been a nice square wave at 440MHz. What he got out of this wire was a mess. You shouldn’t use long wires when probing circuits. That little breadboard wire was a perfect radiator for 440MHz, and the entire setup turned into an antenna.
[Douglas] is running a Kenwood TM-D710A as his amateur radio rig. This radio does APRS stuff, but it requires an external GPS and power source to do it right. GPS receivers are now very small and very cheap, so [Douglas] just stuffed a GPS module inside his radio. The module itself is a GP-20U7, a tiny GPS module the size of a postage stamp, and wired it up to a few pads on the radio PCB.
Proper documentation is important, and when traveling it is commonly achieved via photography. Redundant documentation is often inefficient, and the Camera Restricta — in a commentary on the saturation of photographed landmarks and a recent debate on photographic censorship in the EU — aims to challenge the photographer into taking unique photographs.
Camera Restricta has a 3D-printed body, housing a smartphone for gps data, display and audio output, while an ATTiny85 serves to control the interdicting function of the camera. When the user sets up to take a picture using Camera Restricta, an app running on the phone queries a node.js server that trawls Flikr and Panoramio for geotagged photos of the local area. From that information, the camera outputs a clicking audio relative to the number of photos taken and — if there are over a certain number of pictures of the area — the screen trips a photocell connected to the ATTiny 85 board, retracting the shutter button and locking down the viewfinder until you find a more original subject to photograph.
The IMAV (International Micro Air Vehicle) conference and competition is a yearly flying robotics competition hosted by a different University every year. AKAMAV – a university student group at TU Braunschweig in Germany – have written up a fascinating and detailed account of what it was like to compete (and take first place) in 2016’s eleven-mission event hosted by the Beijing Institute of Technology.
AKAMAV’s debrief of IMAV 2016 is well-written and insightful. It covers not only the five outdoor and six indoor missions, but also details what it was like to prepare for and compete in such an intensive event. In their words, “If you share even a remote interest in flying robots and don’t mind the occasional spectacular crash, this place was Disney Land on steroids.”