raspberry-pi on Purinda Gunasekara

Compiled binaries of Qt 5.3 for the Raspberry Pi (ARMv6) and Pi 2 (ARMv7-A)

Sun, 08 Feb 2015 09:22:33 +1100

At the time of writing Qt 5.4 release existed but I found it has number of bugs that affect multimedia capabilities of the Raspberry Pi.

Download the following binary release and install using following instructions. Instructions assume you still have the user pi in your Raspberry Pi system and make command installed as well (sudo apt-get install make). For the wget command, use the address found in “Download” link below the instructions.

Raspberry Pi WiFi configuration in Raspbian

Sat, 07 Feb 2015 00:49:20 +1100

I recently bought a Raspberry Pi2 and installed Raspbian (version 2015-01-31), it comes with WiFi drivers preinstalled for the Realtek module which I used as my Raspberry Pi WiFi dongle.

So I though things will go smoothly once I have the /etc/wpa_supplicant/wpa_supplicant.conf file configured. So what I did was setup it with my wireless network configuration, which looks like below ( I use WPA2-PSK, with CCMP authentication, if yours is different you may need to configure this right first, I used the wpa_gui command in Raspbian for the following config).

QtMultimedia: FATAL: cannot locate cpu MHz in /proc/cpuinfo

Sun, 10 Aug 2014 23:51:30 +1000

This became a problem for my Raspberry Pi (armv6h) running Archlinux (with a relatively newer kernel). Some users of my Grooveshark server reported some bufferring problems where it stopped streaming songs and reported “FATAL: cannot locate cpu MHz in /proc/cpuinfo”.

Since the Grooveshark server is based on Qt5 I thought the new Qt5.3 version had some multimedia library changes that caused the issue, but turned out the issue is /proc/cpuinfo not producing CPU frequency for the ARM based CPUs. But what program is using a proc cpuinfo to determine CPU frequency without getting the value from sys filesystem exposed by the kernel? or using a monotonic clock as per newer kernels, which would provide timing capabilities without depending on system level changes, turned out there are quite a few programs around that depends on the value specified in “cpuinfo” file in proc filesystem. Including “jack” audio server which is a dependancy for QtMultimedia framework and number of other applications.

Weekend Project: Pi Music Box – Raspberry Pi as a Music streaming device

Sun, 08 Dec 2013 18:58:37 +1100

Get Grooveshark to run on a Raspberry Pi, Let your friends connect to and vote for their favourite songs. Let the majority rule what you hear at home or office.

We used to play songs regularly at work. Most of the time I play Dubstep while rest of the team want to listen to Trance or a different genre, this is where the clash of genres occur. This is where this system would be useful, if you get this running on a network then you can ask people to search their favourite songs and queue them in the system. Based on the votes they/others make for the song, it may float up or down making it either famous or not-so-famous. This makes a playlist of highest voted or popular songs.

Multiple/Second SPI Buses on BeagleBone

Mon, 01 Oct 2012 23:23:52 +1030

How to: Get SPI to work on Beaglebone

If you want just one SPI port running, then most up to date images for beaglebone has enabled them by default.
Location to get pre-compiled images with SPI1 enabled, http://rcn-ee.net/deb/precise-armhf/v3.2.25-psp20/

Enabling SPI0

Step 1

In order to enable userland SPI we need to be able to rebuild the kernel, so grab the Linux source: