Operating Systems Development With The Raspberry Pi

September 2, 2012 by Brian Benchoff 20 Comments

Even though the Raspberry Pi has, from the very beginning, been touted as an educational computer, we’ve seen neither hide nor hare of coursework, lesson plans, or even computer sciencey tutorials using the Raspi. We’re guessing academia works at a much slower pace than the average hardware hacker, but [Alex Chadwick] at Cambridge University has managed to put together an online tutorial on developing an operating system from scratch for the Raspi.

The goal of this tutorial is to throw a budding Raspi tinkerer into the strange and confusing world of registers, hexadecimal, and ARMv6 assembly. After going through the necessary toolchain, [Alex]’s tutorials cover blinking the ‘OK’ LED on the Raspberry Pi using only assembly.

The OS development guide goes on from there to include drawing graphics on the screen and even accepting input from a USB keyboard.

It’s important to point out what [Alex]’s tutorial isn’t; even though this series of tutorials goes through manipulating the bare metal of the Raspberry Pi, don’t expect to be porting UNIX to the Raspi after going through these guides. That being said, after completing these tutorials, you’ll be in a fabulous position for building your own homebrew OS on the Raspberry Pi.

What You Can Do When A Raspberry Pi Teams Up With An Arduino

August 31, 2012 by Mike Szczys 16 Comments

We thought that connecting an Arduino to a Raspberry Pi was overkill, but one thing caught our attention. [Jan Stevens] mentions that the RPi is less expensive than the Ethernet Shield. Interesting. As we looked into his writeup a bit more we began to think he’s onto something. [Jan] uses the PHP serial class to communicate between the RPi and Arduino (dead link; Internet Archive). This ends up being a very inexpensive way to bring some of the more powerful web programming options to your hardware devices.

Sure, he’s just driving three RGB LEDs. But the demo video after the break gives us a glimpse as some of the interface options that become available when an embedded Linux machine is in play. He’s using jQuery, AJAX, PHP, and JSON to name a few. If you want to give this a try yourself you can grab the code from his Github repo. Of course we’re going to want to hear about any projects you develop from this starting point!

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Raspberry Pi Synth Gives A Softsynth Dedicated Hardware

August 31, 2012 by Brian Benchoff 6 Comments

For all the musicians out there, here’s a great use for your Raspberry Pi. All the features you would expect from a nice analog synth are implemented in a Raspberry Pi-based polysynth – dual oscillators, LFOs, and phasers – and it looks like there will be a few more features added before the Raspi synth is released.

Even though the ‘synthesis’ part of the Raspi synth already sounds wonderful, getting MIDI on the Rasberry Pi leaves much to be desired. The creator of the Raspi synth thought about using the GPIO pins as a MIDI interface, but because the GPIO pins cannot run natively at 31250 bps (the MIDI spec), the Raspberry Pi has to waste most of its CPU cycles just listening for MIDI traffic.

Right now the Raspberry Pi synth is controlled by a USB-connected MIDI interface, and as you can hear after the break, sounds wonderful. We can’t wait to hear what this synth will be able to do in a few months’ time.

Continue reading “Raspberry Pi Synth Gives A Softsynth Dedicated Hardware” →

Party Photo Printer Built Around A Raspberry Pi

August 29, 2012 by Mike Szczys 12 Comments

We think [Brian Delacruz] latched on to a good idea with this photo printer project. Instead of building a big photo booth for his party he developed a Raspberry Pi based WiFi photo printer. Right now it’s a prototype that lacks the kind of polish necessary to make a true user-friendly device. But the idea is solid and just waiting for you to improve upon it.

In addition to the RPi he’s using a quality photo printer and a small wireless router. The router simply provides WiFi capabilities for the RPi which is running a web server, mySQL, and FTP. This provides a wide range of upload options which he can work with. Watch the video after the break to see him print a smart phone photo wirelessly.

This can be simplified by using a package like hostapd to use a USB WiFi dongle as an access point. Or if the venue already has Internet access a server could be set up with a QR code to guide people to it. The party starts off with an empty bulletin board and guests would be invited to print and hang their own photos which will go into the host’s guest book/scrap book to remember the event.

The Dark Pi Rises

August 25, 2012 by Caleb Kraft 22 Comments

Ever wonder how an aerospace engineer would build a telepresence rover? Well, if [algorythmic] can be used as our reference, he’d cram a Raspberry Pi AND an Arduino into an RC truck frame. The arduino is being used for motor control while the Raspberry pi is doing the communicating back and forth to the base. He’s using a ps3 controller as his interface and has slightly modified his PS3 eye for better night viewing.

Before you start shouting that using the raspberry pi AND the arduino is massive overkill, let us remind you that people don’t necessarily go buy/build all the parts for each project with a long-term goal in mind. He could have had both sitting there and realized that he didn’t need to add parts to either of them.

With the Raspberry Pi at the helm, this opens up all kinds of possibilities for adding features to make this an autonomous vehicle. Looking around his blog a little bit, it seems he’s done some visual recognition as well as voice control in the past. This could be interesting!

Control Raspi GPIO Pins In The Browser

August 22, 2012 by Brian Benchoff 30 Comments

Now instead of wrangling Python or PHP to do your bidding, [Eric] came up with a way to control the GPIO pins on his Raspberry Pi in a browser.

[Eric] calls his project WebIOPi, and it’s the perfect tool if you’d just like to blink a LED or control a relay over the internet. Simply by pointing his browser to the IP of his Raspi, [Eric] can turn GPIO pins on and off, directly from his desktop browser.

All the code for WebIOPi is available on [Eric]’s Google code page. The UI of [Eric]’s project is fully customizable, so it’s entirely possible to control your garage door from a smart phone simply by loading up a web page hosted on your Raspi and pressing a button.

Right now WebIOPi is only able to turn GPIO pins on and off. That will change as [Eric] implements UART, SPI, and I2C in his project, making it possible to do a lot of cool stuff without having to write much – if any – code.

Building A PBX Setup Around The Raspberry Pi

August 22, 2012 by Mike Szczys 47 Comments

We’re not sure why this use didn’t immediately come to mind when we got our hands on a Raspberry Pi board, but the hardware is almost perfect as a PBX system. PBX, or Private Branch Exchange, is basically an in-house phone system. This guide which [Ward] put together shows you how to do some interesting things with it.

When talking about PBX setups the most common software package is Asterisk. That’s what’s at work here, rolled up with a bunch of other helpful software in an RPi targeted distro called Incredible PBX. All it takes to get up and running is to partition and burn the image to an SD like any other RPi distro. The configuration ends up being most of the work, starting with changing the default password, and moving on to customizing the environment to match your phone numbers and your needs. As with PBX setups on other embedded Linux devices, Google Voice is your best friend. The service will set you up with a free phone number.

This guide doesn’t delve into hardware connected hand sets. You’ll need to use a SIP phone. But that’s easy enough as there are free apps for most smart phones that will do the trick.

[Thanks Jamie]