raspberry pi

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Raspberry Pi - rpi

Operating Systems Development With The Raspberry Pi

September 2, 2012 by 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.

Raspberry Pi Synth Gives A Softsynth Dedicated Hardware

August 31, 2012 by 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.

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Control Raspi GPIO Pins In The Browser

August 22, 2012 by 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.

Turning A Keyboard Into A Computer With A Raspberry Pi

August 14, 2012 by 28 Comments

Only 80s kids will get this: remember when computers had built-in keyboards, like the Apple II line, or the Commodore 64? That’s a form factor duplicated by case modders many times over the years, but [preamp]’s project is the first time its been done using a Raspi (German, Google translation).

For his build, [preamp] used what he considers the best keyboard in the world, the Cherry G80-3000. Except for the HDMI port, just about every plug was moved to the back side of the keyboard with the help of an Ethernet jack, a USB hub, and RCA jack. Audio is missing, but for an extremely portable system [preamp]’s RaspCherry Pi is at the top of its class.

We were wondering when someone would shove a Raspi into a keyboard, and we couldn’t be happier that [preamp] chose a Cherry keyboard for his build; they’re wonderful input devices second only to the 8 pound behemeoth used to write this post.

Not Quite Building A Raspi Arduino Bridge

August 5, 2012 by 9 Comments

 

A few months ago, [Omer] sent in a Raspberry Pi to Arduino bridge he’s been working on called Ponte. Now that he’s gotten a few assembled, he can actually test out his ideas for combining the powerful Raspi with the ubiquitous Arduino.

Ponte revision 0 used a pair of 12-bit analog to digital converters, but during the soldering and debugging phase of development [Omer] discovered a few things were wrong with his original design. The FETs on the fabricated boards had the drain and source pins mixed up, but that problem was easily solved with a bit of board surgery.

The worst problem was the mechanical design of Ponte rev. 0 – the power jack on the Ponte is directly above the Raspi’s USB port, meaning it’s impossible to plug the Ponte into the Pi.

[Omer] is working on these problems and should have  the revised boards completed shortly. A few people have asked where they can get a Ponte, but right now there are no plans to assemble and ship boards. That may change, but for now if might be worth bugging [Omer] to put his new and improved Ponte (with an 8-port I2C port expander!) up on SeeedStudio

 

Adafruit’s Custom Rasp Pi Distro Eases Some Pain

August 3, 2012 by 22 Comments

Many of you have still not yet received your Raspberry Pi. When you do, you’ll find that there is work to be done in the operating system to get things working as you might want them to.  The wonderful folks over at Adafruit have tackled this by releasing their own distribution of Linux for the Raspberry Pi.

Based on the shipped distribution “Wheezy”, Adafruit’s distribution “Occidentalis v0.1. Rubus occidentalis” or “the Black Raspberry” now includes the following:

 

Checking Network Status With A Traffic Light

July 29, 2012 by 14 Comments

If you’ve ever dealt with a buggy Internet connection, you know how frustrating it can be. This project takes the guesswork out of mashing F5 over and over, or simply walking over to your router and ‘turning it on and off again.’

Necessity is the mother of invention, and when the folks at the Bitlair hackerspace in Amersfoort, Netherlands got tired of opening up a terminal to see if their network connection was down at this weekend’s Haxogreen camp they did what any self-respecting hackerspace would do: make a traffic light monitor the Internet.

The traffic light is controlled by a Raspberry Pi the Bitlair folks had lying around attached to a spare traffic light they somehow obtained with a relay. Green means the Raspi can reach 8.8.8.8, red means there is no connection, and flashing lights means there is packet loss.

Not bad for a project put together in a few hours. Now if we only knew how they obtained a traffic light, ‘just lying around.’

Video after the break.

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