Getting paid to do what you enjoy is a special treat. A machinist and fabricator by trade — hobbyist hacker by design — [spdltd] was commissioned to build a mechanical art installation with a steampunk twist. Having complete creative control, he convinced his client to let him make something useful: a giant electro-mechanical clock.
Pieced together from copper, brass, steel, aluminium, and stainless steel, this outlandish design uses an Arduino Yun — a combination Linux and Arduino microcontroller board — to control the stepper motor and query the internet for the local time. Upon boot, the clock auto-calibrates by rotating the clock face until a sensor detects an extra peg and uses that to zero on twelve o’clock; the Yun then grabs the local time over the WiFi and sends the stepper motor a-spinning ’till the correct time is displayed.
At first glance, you may find it hard to get an accurate read of what time it is, but an accent piece’s pegs denote the quarter hour once it lines up with the notch above each hour. At least this one doesn’t require you to match colours or do much math to check the time.
Continue reading “Steampunk-Inspired Art Clock!”
The ev3dev Linux distribution got an update this month. The distribution targets the Lego EV3 which is a CPU Lego provides to drive their Mindstorm robots. The new release includes the most recent kernel and updates from Debian 8.8. It also contains tools needed for some Wi-Fi dongles and other updates.
If you haven’t seen ev3dev before, it is quite simply Linux that boots on the EV3 hardware using an SD card. You don’t have to reflash the computer and if you want to return to stock, just take out the SD card. You can also use ev3dev on a Raspberry Pi or BeagleBone, if you like. There’s a driver framework included for handling sensors, motors, and other items using the file system.
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Linux users–including the ones at the Hackaday underground bunker–tend to fall into two groups: those that use vi and those that use emacs. We aren’t going to open that debate up again, but we couldn’t help but notice a new item on GitHub that potentially negates one of the biggest complaints non-vi users have, at least for vim which is the most common variant of vi in use on most modern systems. The vim keybinding makes vim behave like a “normal” editor (and to forestall flames, that’s a quote from the project page).
Normally vi starts out in a command mode that it calls normal mode. Pressing a key will execute an editing command, unlike most other modern editors which just insert characters into the open file. For example, pressing x will delete a character. This surprises most people who aren’t familiar with vi. In all fairness, there are other older editors that work this way, but they usually were not screen-oriented.
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What do you get when you cross an ARM-based Linux PC and an RTL-SDR? Sounds like the start of a joke, but the answer is Outernet’s Dreamcatcher. It is a single PCB with an RTL-SDR software defined radio, an L-band LNA, and an Allwinner A13 processor with 512MB of RAM and a 1 GHz clock speed. The rtl-sdr site recently posted a good review of the $99 board.
We’ll let you read the review for yourself, but the conclusion was that despite some bugs, the board was no more expensive than pulling the parts together separately. On the other hand, if you uses, for example, a Raspberry Pi 3, you might expect more support and more performance.
Despite the L-band hardware, there is a bypass antenna jack that allows you to receive other frequencies. There’s also two SD slots, one to boot from and another for storage. Several pieces of software had trouble running on the somewhat sluggish CPU, although some software that is optimized for the particular processor used fared better. You can read the details in the review.
The board is interesting, although unless you have a special packaging problem, you are probably as well off to combine a Pi and a dongle, as we have seen so many times before. If you have more horsepower you can even make the Pi transmit, although we’d suggest some filtering if you were going to do that for real.
File systems are one of those things that typical end users don’t think much about. Apparently, [seaQueue] isn’t a typical end user. He’s posted some instructions on how to run an alternate file system–btrfs–on the Raspberry Pi.
The right file system can make a big difference when it comes to performance and maintainability of any system that deals with storage. Linux, including most OSs for the Raspberry Pi, uses one of the EXT file systems. These are battle-hardened and well understood. However, there are other file systems, many of which have advanced features superior to the default file system for some applications.
Btrfs, often pronounced “butter eff ess”, begin life at Oracle and was born from an idea in an IBM paper. It offers advanced features like pooling, snapshots, and the ability to fuse multiple devices into one logical device. One notable feature the file system offers is copy-on-write. That means file copies can share common blocks as long as they stay common. Compression is available, as is seeding a file system with read-only storage, which could be very useful in some embedded systems. You can also configure several types of RAID using nothing but btrfs. You can see a video presentation about features of btrfs below.
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When working collaboratively, it is handy to be able to see someone’s screen. For the GUI, there are plenty of options. There are a few ways to share a terminal screen (such as screen, tmux, and tmate). Now there’s a new terminal sharing program based on the Go language from developer [spolu] called Warp.
Unlike some other solutions, Warp is simple, focuses only on sharing a shell session, and does not require ssh or a central server (sort of). Despite not using ssh, the connection between machines is secure. However, if you are really worried about security, note that the session name (which is not published) is all anyone needs to connect. Probably should make it hard to guess.
Continue reading “Scotty, Warp Screen Sharing!”
JeVois is a small, open-source, smart machine vision camera that was funded on Kickstarter in early 2017. I backed it because cameras that embed machine vision elements are steadily growing more capable, and JeVois boasts an impressive range of features. It runs embedded Linux and can process video at high frame rates using OpenCV algorithms. It can run standalone, or as a USB camera streaming raw or pre-processed video to a host computer for further action. In either case it can communicate to (and be controlled by) other devices via serial port.
But none of that is what really struck me about the camera when I received my unit. What really stood out was the demo mode. The team behind JeVois nailed an effective demo mode for a complex device. That didn’t happen by accident, and the results are worth sharing.
Continue reading “JeVois Machine Vision Camera Nails Demo Mode”