Raspberry Pi

1853 Articles

Learning Python With Tron Radio

January 20, 2015 by 19 Comments

[5 Volt Junkie] has built his share of Arduino projects, but never anything with Python, and certainly never anything with a GUI. After listening to Internet radio one day, a new idea for a project was born: a Raspberry Pi with a small touchscreen display for a UI and displaying soma.fm tracks. It’s finally finished, and it’s a great introduction to Python, Pygame, and driving tiny little displays with the Pi.

Playing soma.fm streams was handled by mpd and mpc, while the task of driving a 2.8″ TFT LCD was handled by the fbtft Linux framebuffer driver. This left [5 Volt Junkie] with the task of creating a GUI, some buttons, and working out how to play a few streams. This meant drawing some buttons in Inkscape, but these were admittedly terrible, so [5 Volt Junkie] gave up and turned on the TV. Tron Legacy was playing, giving him the inspiration to complete his Tron-themed music player.

The result of [5 Volt Junkie]’s work is a few hundred lines of Python with Pygame and a few multicolor skins all wrapped up in a Tron theme. It looks great, it works great, and it’s a great introduction to Python and Pygame.

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Tracking Power Usage With A Raspi

January 18, 2015 by 29 Comments

With tiny, Internet-connected computers everywhere these days, home automation is finally hitting it big. [Jelora] was looking for a few more home automation projects and realized his electric meter had a pair of ‘digital information outputs’. With a Raspberry Pi and a few bits of wire, he figured out how to read this digital output and put a log of his electricity consumption up on the web.

The digital output on [Jelora]’s meter is a bit odd; it’s 1200 bps, 7 bits per character, parity, with one stop bit. It’s also a 50 kHz AC signal for a binary ‘0’ and nothing for a binary ‘1’. To read this signal, [Jelora] is using a diode to throw out half the signal, a 6N138 optoisolator so the Pi isn’t connected directly to the meter, and a small cap to smooth out the signal. Simple, and it works.

This cleaned up signal is then connected to serial to USB chip and a PHP script scrapes the data every minute. The data received from the meter is stored in a data base along with a few other bits of information: if the meter is being charged peak or off-peak rates, and the price per kWh. All this is saved on an IDE hard drive (more reliable than the SD card, surprisingly), and a ‘electricity cost per day’ is plotted on a nifty graph and served up by the Raspberry Pi.

Handheld Linux Terminal Gets An A+

January 17, 2015 by 40 Comments

Are you all thumbs when it comes to Linux? If you follow [Chris]’s guide to building a handheld Linux terminal, that particular condition could work to your advantage. His pocket-sized machine is perfect for practicing command line-fu and honing your scripting skills on the go.

[Chris]’s creation is built around a Raspberry Pi A+ that he stripped to its essentials by removing the GPIO pins, HDMI and USB ports, the audio port, and the camera and display ports. It’s housed in a pair of plastic 2.5″ hard drive enclosures connected with a piano hinge, making it about the size of a Nintendo DS. The display is an Adafruit PiTFT touch screen and in order to save space, he soldered it directly to the Pi.

The 2.4GHz wireless thumb keyboard has all the special characters necessary for Linuxing, but the four USB ports from a dismantled hub provide flexibility. If [Chris] were to make another one, he might use this slightly larger screen from Tindie and add some charging ports to the case.

[Thanks for the tip, ar0cketman]

RasPi Traffic Monitor

Dedicated Automobile Traffic Monitor With Raspberry Pi

January 6, 2015 by 31 Comments

[j3tstream] wanted an easier way to monitor traffic on the roads in his area. Specifically, he wanted to monitor the roads from his car while driving. That meant it needed to be easy to use, and not too distracting.

[j3tstream] figured he could use a Raspberry Pi to run the system. This would make things easy since he’d have a full Linux system at his disposal. The Pi is relatively low power, so it’s run from a car cigarette lighter adapter. [j3tstream] did have to add a custom power button to the Pi. This allows the system to boot up and shut down gracefully, preventing system files from being corrupted.

After searching eBay, [j3tstream] found an inexpensive 3.2″ TFT LCD touchscreen display that would work nicely for displaying the traffic data. The display was easy to get working with the Pi. [j3tstream] used the Raspbian linux distribution. His project page includes a link to download a Raspbian image that already includes the necessary modules to work with the LCD screen. Once the image is loaded, all that needs to be done is to calibrate the screen using built-in operating system functions.

The system still needed a data connection. To make things simple and inexpensive, [j3tstream] used a USB WiFi dongle. The Pi then connects to a WiFi hot spot built into his 4G mobile phone. To view the traffic map, [j3tstream] just connects to a website that displays traffic for his area.

The last steps were to automate as much as possible. After all, you don’t want to be fumbling with a little touch screen while driving. [j3tstream] made some edits to the LXDE autostart file. These changes automatically load a browser in full screen mode to the traffic website. Now when [j3tstream] boots up his Pi, it automatically connects to his WiFi hotspot and loads up local traffic maps.

The Smallest Portable Pi

January 3, 2015 by 17 Comments

What do you get when you take an extremely small Raspberry Pi clone and stuff it inside a Game Boy Advance SP? We don’t know what to call it, but it’s probably one of the best portable gaming machines ever made, able to run emulators ranging from the Apple II to playing Quake III natively on a tiny flip-top display.

This isn’t the first time we’ve seen [frostedfires]’ work on a tiny system stuffed into a Game Boy. The initial post on this build over on the bacman forums just covered the basics – getting an Odroid W up and running, and putting Quake III on the tiny display. Now that the build is complete, we can get a look at what it takes to turn a Raspberry Pi clone into one of the smallest portable projects we’ve ever seen.

Using a Raspi clone as the only component in a tiny portable emulation station isn’t possible, so [frostefires] added a few other bits of electronics to make everything work. There’s a joystick from a PSP in there to work as the mouse, a few extra buttons in addition to the stock Game Boy ones, A USB hub, WiFi adapter, speaker and amplifier, a battery and the related charging electronics, and a Teensy 3.1 to handle all the input.

It’s a very impressive build that can run emulators ranging from the Apple II to later generation Nintendo consoles and handhelds (including the Game Boy Advance), but since the HDMI connector is availble on the outside of the case, [frostedfires] can also use this as a tiny, portable media center. Check out the video below to see this Game Boy in action, playing Mario Kart and 1080p video.

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Multiplexing Pi Cameras

December 19, 2014 by 39 Comments

The Raspberry Pi and its cool camera add-on is a great way to send images and video up to the Intertubes, but what if you want to monitor more than one scene? The IVPort can multiplex up to sixteen of these Raspi camera modules, giving the Pi sixteen different views on the world and a ridiculously high stack of boards connected to the GPIO header.

The Raspberry Pi’s CSI interface uses high-speed data lines from the camera to the CPU to get a lot of image data quickly. Controlling the camera, on the other hand, uses regular old GPIOs, the same kind that are broken out on the header. We’ve seen builds that reuse these GPIOs to blink a LED, but with a breakout board with additional camera connectors, it’s possible to use normal GPIO lines in place of the camera port GPIOs.

The result is a stackable extension board that splits the camera port in twain, allowing four Raspi cameras to be connected. Stack another board on top and you can add four more cameras. A total of four of these boards can be stacked together, multiplexing sixteen Raspberry Pi cameras.

As far as the obvious, ‘why’ question goes, there are a few interesting things you can do with a dozen or so computer controlled cameras. The obvious choice would be a bullet time camera rig, something this board should be capable of, given its time to switch between channels is only 50ns. Videos below.

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Meme Themed Pinball Machine – Much Flipping, Y U No Win?!

December 18, 2014 by 10 Comments

Summoning 4chans, 9gags, Reddits and other denizens of easily-digested content, Liberty Games stripped apart a dilapidated “Baby Doll” pinball arcade machine and turned it into this meme-spouting monstrosity. A complete redo of the vinyl and graphics to sport dozens of familiar internet tropes was first, then they had Shapeways create internal scenery and finally some electronics were added to spice things up.

We have seen PINMAME-based digital machines but this took a different path. Pinball machines this old pre-date common transistors so they rely on electro-mechanicals for everything. This made hacking the machine challenging so the team intercepted most of the signals and tied them into a Raspberry Pi with a Pi-face interface board. A videoscreen was added to the scoreboard, triggering all manner of memey videos and sounds according to actions performed and unlocked on the screen.

If you yearn for expired pranks of years gone by and are bad at pinball, you are in luck. Losing the game gets you Rickrolled – over and over again. On the plus side, Nyan Cat rockets away to bonuses and even the Admiral himself warns you of impending danger.

We resisted the urge to write this article as a chain of one meme to the next, you will get plenty of that from the well-documented project conversion and the following video. Someone in the comments will probably make a list of all memes.

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