Developing A Thermostat For A Heat Pump That Only Has A Timer

November 12, 2012 by Mike Szczys 10 Comments

The heat pump which cools [Chris LeBlanc’s] home lacks the sort of control he was looking for. It’s just got a timer, which switches it off automatically. He wanted to the ability to schedule the cooling cycle like you would with a thermostat-driven arrangement. He ended up build his own controller to automate the cooling process.

The heat pump came with an IR remote control which provides the access point for the project. [Chris] set out to emulate the remote protocol which saved him the trouble of having to crack open the unit and wire in a controller. He went with the IR Toy from Dangerous Prototypes as this device is able to record and transmit IR signals — it’s basically a universal remote for your USB port. His Raspberry Pi, seen to the left, controls the system. It’s connected to the red IR Toy board via a USB hub which is used to interface a WiFi dongle as well. The system works alongside Google Calendar to allow [Chris] to schedule his home’s cooling just by adding an appointment. A Python script queries the calendar, then selects and sends the appropriate IR command. He shows off the build in the clip after the break.

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Raspberry Pi Gets RISC OS, Can Now Play Elite

November 8, 2012 by Brian Benchoff 32 Comments

The processor in the Raspberry Pi – an ARM11 built by Broadcom – actually has a long and storied history. Much as how the Intel i7 in a top-of-the-line desktop can still run code written for the original IBM PC, the ARM chip in the Raspberry Pi is also based on decades-old technology.

The first ARM-based computer was the Acorn Archimedes, a mid-80s computer with 512kB of RAM and no hard drive. The Archimedes ran RISC OS, a very nice graphical operating system written explicitly for the ARM architecture. RISC OS is now available for the Raspberry Pi, finally bridging the gap between educational computers from 1987 and 2012.

Of course, a very much updated version of 25-year-old operating system running on a Raspberry Pi doesn’t mean much without a ‘killer app,’ does it? For the original Acorn Archimedes the killer app – and one of the best video games of the 80s – was Elite, a space trading and combat game that featured vector-style ships. [Pete Taylor] downloaded the Raspi RISC OS image and got Elite running using an Archimedes emulator and, of course, the Archimedes port of Elite.

It’s a pretty neat development if you’re in to alternative OSes and one of the best space-based games ever made. Well worth a download, at the very least.

Turning The Raspberry Pi Into A Cocktail MAME Coffee Table

November 4, 2012 by Brian Benchoff 35 Comments

Ah, the cocktail arcade cabinet. With the right design, its able to blend right in to any living room decor, much more than any traditional stand-up cabinet, at least. [graham] over on Instructables didn’t tear apart a 30-year-old arcade cabinet for his new coffee table. Instead, he built one from scratch, connected it to a Rasberry Pi, and brought hundreds of arcade classics right in front of his couch.

The build began by cutting up some wood to house the 24″ LCD screen, Raspi, and arcade controls. The LCD screen is supported with a rather clever system of cross braces screwed into the VESA mount, and of course a piece of perspex protects the screen from the inevitable spills and scratches.

The joystick two blue ‘player’ buttons and the player 1 and player two buttons are wired directly to the GPIO pins of the Raspberry Pi. The Raspi boots up into a selection of MAME games, but there’s also an option for opening up the window manager and browsing the web.

It’s a very neat build that’s a lot smaller (and easier to build) than a traditional cocktail cabinet. As [graham] is using it for a coffee table, it might get more use than a regular MAME build, to boot.

Controlling Google TV From A Raspberry Pi (or Other Networked Devices)

November 1, 2012 by Mike Szczys 9 Comments

Google TV is a network connected television. It does what you would think: plays television programs, streams media from the internet, and allows you to open URLs on your TV. But one nice feature is that it can also be controlled over the network rather than just via an IR remote. Google publishes apps which make this simple with a smartphone. But the communications protocols are open source, so [Leon Nicholls] wrote a Google TV remote control library in Java.

The video after the break shows him pairing a Raspberry Pi with his television. The image above is the pairing verification code you must enter on the remote hardware before control is authorized. Apparently this is a step that needs to happen every time if using Google’s Anymote library. [Leon] improved that, by saving the pairing data so that the first authorization is all that it takes.

He figures this could be used for home automation. We’re not sure what we’d use it for but we’d love to hear your ideas in the comments.

One-button Audiobook Player Made From A Raspberry Pi

November 1, 2012 by Mike Szczys 35 Comments

[Michael Clemens] was looking for gifts for his Grandmother’s 90th Birthday. She is visually impaired and loves to be able to listen to audiobooks. The problem is that she doesn’t really get the hang of using electronics. He made things easy by building her a one-button audiobook player.

The Raspberry Pi board is a perfect solution for this project. It’s cheap, it has an audio port, it has storage for the books on the system SD card, and it runs Linux. The last part is key as it made things very simple when [Michael] started pulling together the various components.

When the RPi is powered up it drops immediately into a Python script which loads the audio track and places the music player daemon in pause. The yellow button seen above works as a play/pause button when clicked. If the listener misses something she can hold the button for more than four seconds to go back one track. Loading new books is easy too. [Michael] copies the files onto a thumb drive with a special volume label. When plugged into the RPi USB port the script automatically copies the book and starts playing when the drive is removed. He included a video demo on his project page linked above.

PCA9517 I2c Translator A Perfect Companion For Raspberry Pi Hardware Add-ons

October 26, 2012 by Mike Szczys 10 Comments

The rig pictured above works as an Internet connected temperature sensor which sends [Zaion] an email with a graph of the change over time. This in itself is interesting, but one part in particular caught our eye. He’s using an i2c temperature sensor , and we think the PCA9517 Level-Translating I2C Bus Repeater that makes it possible is a perfect match for the RPi.

This is a Texas Instruments part. You can find more about it from the company’s product page. The key words in the name of the chip are ‘Level-Translating’. This has two bus connections, each with variable voltage levels. On side A the bus can be 0.9V to 5.5V. On side B the bus range is 2.7V to 5.5V. Since the Raspberry Pi I/O pins operate at 3.3V this could connect to the B side, give you the ability to interface with i2c parts rated for lower or higher voltages. This is especially handy for folks who started with the Arduino and own mostly 5V compliant prototyping hardware.

The part comes in a SOIC package, which you can easily hand solder and will costs around $1 depending on the supplier.

Rasperry Pi: Now Mostly Open Source

October 24, 2012 by Brian Benchoff 70 Comments

If you’ve been following the developments of building Android, Chromium, and other OSes for the Raspberry Pi, you’ll come across a common theme. The drivers for the Raspi’s chip are closed source and protected by Broadcom with an NDA. This limits the ability of devs to take on projects that involve messing around deep inside the CPU.

Today, this is no longer the case. The CPU on the Raspberry Pi is now the first ARM-based system with fully functional, vendor-provided drivers.

Previously, the drivers for OpenGL ES, OpenMax, and other goodies inside the ARM chip have been closed source, available only to the Raspberry Pi foundation and those willing to sign a non-disclosure agreement with Broadcom. With this release, the drivers are open source, allowing the devs behind the Android, Chromium, Haiku, *BSD, and the RISC OS to dig deep into the Broadcom drivers and get their projects working.

The new files are available in the Raspberry Pi git, just waiting for devs to take a look at it.