Since the introduction of the Raspberry Pi, the embedded Linux scene has been rocked by well supported hardware that is produced in quantity, a company that won’t go out of business in six months, and a huge user base. Yes, there are a few small problems with the Raspberry Pi and its foundation – some stuff is still closed source, the Foundation itself plays things close to their chests, and there are some weird binary blobs somebody will eventually reverse engineer. Viewed against the competition, though, nothing else compares.
Here’s the NanoPi Neo, the latest quad-core Allwinner board from a company in China you’ve never heard of.
The NanoPi Neo is someone’s answer to the Raspberry Pi Zero, the very small and very cheap single board Linux computer whose out-of-stock percentage has led some to claim it’s completely fake and a media conspiracy. The NanoPi Zero features an Allwinner H3 quad-core Cortex-A7 running at 1.2 GHz, 256MB RAM, with a 512MB version being released shortly. Unlike the Raspberry Pi Zero, the NanoPi Neo features a 10/100 Ethernet port. No, it does not have PoE.
As with anything comparing itself to the Raspberry Pi Zero, only two things are important: size and price. The NanoPi Neo is a mere 40mm square, compared to the 65x30mm measurements of the Pi Zero. The NanoPi Neo is available for $7.99, with $5 shipping to the US. Yes, for just three dollars more than a Pi Zero with shipping, you get a poorly supported Linux board. What a time to be alive.
If you’re looking for another wonderful tale of what happens with cheap, powerful ARM chips and contract manufacturers in China, check out my review of the Pine64.
In a clever bit of miniaturization, [JediJeremy] has nearly completed a gyro-mouse controller for a Raspberry Pi Zero! Ultimately this will be a wearable Linux-watch but along the way he had some fun with the interface.
Using the MPU6040 gyroscope/accelerometer card from a quadcopter, [JediJeremy] spent a week writing the driver to allow it to function as a mouse. Strapping an Adafruit 1.5″ PAL/NTSC LCD screen and its driver board to the Zero with rubber bands makes this one of the smallest functional computer and screen combos we’ve seen. Simply tilt the whole thing about to direct the cursor.
It presently lacks any keyboard input, and [JediJeremy] has only added a single button for clicking, but look at this thing! It’s so tiny! In his own words: “I think this is the first computer that I can accidentally spill into my coffee, rather than vice versa.”
Continue reading “Raspberry Pi Zero Becomes Mighty Miniature Minecraft Machine”
If you’ve taken any digital signal processing classes at a college or university, you’ve probably been exposed to MATLAB. However, if you want to do your own work, you might think about Linux and one of the many scientific computing applications available for it.
[David Duarte] recently published a three-part tutorial on using Octave to do scientific audio processing. The first part covers basic reading, writing, and playing of audio files. Part two covers synthesis of signals, plotting, and some basic transformations. Modulation is the topic of the third part. If you prefer your tutorials on video, you can check out the video below.
We’ve talked about MATLAB before in the context of message cracking. Then again, some of the best signal processing is done by humans. If you don’t like Octave, you might try Scilab, another Linux package that is similar. There’s also Freemat, Sage, and Spyder. Of course, you can also run MATLAB under Linux.
Some tools in a toolbox are versatile. You can use a screwdriver as a pry bar to open a paint can, for example. I’ve even hammered a tack in with a screwdriver handle even though you probably shouldn’t. But a chainsaw isn’t that versatile. It only cuts. But man does it cut!
AWK is a chainsaw for processing text files line-by-line (and the GNU version is known as GAWK). That’s a pretty common case. It is even more common if you produce a text file from a spreadsheet or work with other kinds of text files. AWK has some serious limitations, but so do chainsaws. They are still super useful. Although AWK sounds like a penguin-like bird (see right), that’s an auk. Sounds the same, but spelled differently. AWK is actually an acronym of the original author’s names.
If you know C and you grok regular expressions, then you can learn AWK in about 5 minutes. If you only know C, go read up on regular expressions and come back. Five minutes later you will know AWK. If you are running Linux, you probably already have GAWK installed and can run it using the alias awk. If you are running Windows, you might consider installing Cygwin, although there are pure Windows versions available. If you just want to play in a browser, try webawk.
Continue reading “Gawking Text Files”
Sometimes you might need to use assembly sometime to reach your project objectives. Previously I’ve focused more on embedding assembly within gcc or another compiler. But just like some people want to hunt with a bow, or make bread by hand, or do many other things that are no longer absolutely necessary, some people like writing in assembly language.
In the old days of DOS, it was fairly easy to write in assembly language. Good thing, because on the restricted resources available on those machines it might have been the only way to get things to fit. These days, under Windows or Linux or even on a Raspberry Pi, it is hard to get oriented on how to get an assembly language off the ground.
Continue reading “Linux: Assembly Required”
One of the nice things about the Raspberry Pi is that it runs Linux and you can do a lot of development right on the board. The converse of that is you can do a lot of development on a Linux desktop and then move things over to the Pi once you get the biggest bugs out. However, sometimes you really need to run code on the actual platform.
There is, however, an in-between solution that has the added benefit of upping your skills: emulate a Pi on your desktop. If you use Linux or Windows on your desktop, you can use QEMU to execute Raspberry Pi software virtually. This might be useful if you don’t have a Pi (or, at least, don’t have it with you). Or you just want to leverage your large computer to simplify development. Of course we would be delighted to see you build the Pi equivalent of the Tamagotchi Singularity but that’s a bit beyond the scope of this article.
Since I use Linux, I’m going to focus on that. If you insist on using Windows, you can find a ready-to-go project on Sourceforge. For the most part, you should find the process similar. The method I’ll talk about works on Kubuntu, but should also work on most other Debian-based systems, including Ubuntu.
Continue reading “Virtually Free Rapsberry Pis”
Android-based TV sticks should be in more projects. They are readily available and inexpensive. They have a lot of horsepower for the price, and they can even boot a mainline Linux kernel, unlike some single-board computers we know. They’re smaller than the Pi Zero, so they’ll fit almost anywhere.
The one thing they don’t have, though, is I/O. Sure, it’s got a USB port, but that’s just about it. [Necromant] considered these problems and created a carrier board that fixes all that.
- On-board 3A DC-DC. You can power the whole thing with anything from 7 to 24 volts DC
- A 4-Port USB hub
- An ATtiny 2313, connected to the hub via the V-USB stack
- 2 USB ports on the back, with power control via GPIO lines
- One USB port on the front (with power always on)
- 3 relays
- Fits a common anodized aluminum enclosure
The ATtiny code is on GitHub and allows for full I/O control, saving the state of the pins in EEPROM, and providing up to eight channels of servo control. The device connects through the USB port (consuming one port on the hub).
Repurposing consumer gear for embedded service is nothing new. We’ve seen it with phones. We’ve even seen remotes used as a mouse. But this is such a nice template for adding cheap and easy computing power to your projects that we’re surprised we don’t see it more often. Why aren’t you hacking a TV stick into your projects?