Month: October 2013

Raspberry Pi based Content Delivery Platform

 

The Raspberry Pi is a credit-card-sized single-board computer developed in the UK by the Raspberry Pi Foundation with the intention of promoting the teaching of basic computer science in schools. The Raspberry Pi has a Broadcom BCM2835 system on a chip (SoC), which includes an ARM1176JZF-S 700 MHz processor (The firmware includes a number of “Turbo” modes so that the user can attempt overclocking, up to 1 GHz, without affecting the warranty),VideoCore IV GPU, and was originally shipped with 256 megabytes of RAM, later upgraded to 512MB. It does not include a built-in hard disk or solid-state drive, but uses an SD card for booting and long-term storage. The Foundation’s goal is to offer two versions, priced at US$25 and US$35

Content Delivery Solution

Lets see how a Raspberry pi based content delivery solution can be developed for educational institutes or anyone who needs it. Educational institutes have primary objective to enable learning through various interactive programmable delivery of content. The setup can be installed in lounge areas or even in school classrooms. Content can be customized as per need and pre-added to a batch file based application that functions like a jukebox that open the YouTube video link using the default internet browser. Making the content delivery changes will be a custom requirement and can be remotely administered. The prototype application can be administered by modifying the configuration files that directly download content from LAN or any other source.

How can it be done ? – The Technology

FreeBSD  installed on the sd card and Apache based web application for each school/university as per need. Once device is started it boot the OS and start the web app on display with default player.

What Application?

Custom prototype application initially can be installed for demonstration that will play the YouTube demo videos.

Detailed Design – Block Diagram

Block diagram consists of Raspberry Pi device (with casing) connected to the LAN. The device is connected to a TV and speaker. When the device is started it will booted with output to TV and speakers as per the configuration setup. When the device is switched off no video is played.

Image

Specifications

Model A: Target price:         US$ 25           

Model B: Target price:         US$ 35

SoC: Broadcom BCM2835 (CPU, GPU, DSP, SDRAM, and single USB port)

CPU:   700 MHz ARM1176JZF-S core (ARM11 family)

GPU:  Broadcom VideoCore IV

              OpenGL ES 2.0 (24 GFLOPS)

              MPEG-2 and VC-1 (with license),

              1080p30 h.264/MPEG-4 AVC high-profile decoder and encoder

Memory (SDRAM):

Model A: 256 MB (shared with GPU)          

Model B: 512 MB (shared with GPU)

USB 2.0 ports:           1 (direct from BCM2835 chip)          

                            2 (via the built in integrated 3-port USB hub)

Video input:   A CSI input connector allows for the connection of a RPF designed camera module

Video outputs:           Composite RCA (PAL and NTSC),

                             HDMI (rev 1.3 & 1.4),

                             raw LCD Panels via DSI

                            14 HDMI resolutions from 640×350 to 1920×1200 plus various PAL and NTSC standards.

Audio outputs:           3.5 mm jack, HDMI, and, as of revision 2 boards, I²S audio  (also potentially for audio input)

Onboard storage:      SD / MMC / SDIO card slot (3,3V card power support only)

Onboard network:    None   10/100 Ethernet (8P8C) USB adapter on the third port of the USB hub

Low-level peripherals:          8 × GPIO, UART, I²C bus, SPI bus with two chip selects, I²S audio +3.3 V, +5 V, ground

Power ratings:           Model A: 300 mA (1.5 W)

Model B: 700 mA (3.5 W)

Power source:            5 volt via MicroUSB or GPIO header

Size:    85.60 mm × 53.98 mm (3.370 in × 2.125 in)

Weight:           45 g (1.6 oz)

Operating systems:    Arch Linux ARM, Debian Linux, Fedora, FreeBSD, Plan 9, Raspbian OS, RISC OS,Slackware Linux

References

  1. Boot file config settings http://elinux.org/RPi_config.txt
  2. MPEG2 license key: http://www.raspberrypi.com/
  3. Quick Start Guide: http://www.raspberrypi.org/quick-start-guide
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Keyboard Tab Key Access and Applying CSS3 styles For list items in ie8

We can provide Tab key access for list items in IE8  browsers by either using an overlay button and giving tabindex or by applying tab-index as zero .

For applying css3 styles and use the list item as a button ,this overlay concept will serve.

For example

<li class=”true” style=”display: list-item;”>
<input class=”rollover_scenario_btn” type=”button” tabindex=”1″ >
</li>
the example above can serve css3 styles and tab key access.
or for tab key access can be given using
<li class=”true” style=”display: list-item;” tabindex=”0″>