Raspberry Pi - Week 4

<<< back to Raspberry Pi

Review

• Installed software with apt-get. (including festival).
• Installed and ran VNC to get a remote desktop on the machine.
• Ran a simple python script to synthesize speech ( example)
• Another python tutorial: Learn Python the Hard Way

Video Playback

• Omxplayer is a video player specifically made for the Raspberry PI's GPU made by Edgar (gimli) Hucek from the XBMC project.
  • omxplayer comes pre-installed on our raspbian distribution.
• Controlling omxplayer with hotkeys:
  • http://elinux.org/Omxplayer#Hotkeys
• Try it out, by hand.
  • Copy a movie file to your raspberry pi using scp.
  • movie needs to be mp4 format.
    • you can transcode with ffmpeg:
      • ffmpeg -i mouse_brain.wmv mouse_brain.mp4
  • run omxplayer and try hotkey controls
    • omxplayer ~/Movies/mouse_brain.mp4<code>
  • notice responsiveness.
• We will send those via STDIN in python:
  • http://stackoverflow.com/questions/12755968/sending-arrow-keys-to-popen

ffmpeg

• install homebrew
• <code>brew install ffmpeg

GPIO

• pin over-voltage protection circuits - http://elinux.org/RPi_Tutorial_EGHS:GPIO_Protection_Circuits
• light example - https://projects.drogon.net/raspberry-pi/gpio-examples/tux-crossing/gpio-examples-1-a-single-led/
  • uses wiringPI, command line tool, for ex:gpio
  • installed using git - https://projects.drogon.net/raspberry-pi/wiringpi/download-and-install/

through python

• follow adafruit - http://learn.adafruit.com/adafruits-raspberry-pi-lesson-4-gpio-setup/overview
  • Rpi.GPIO -
  • requires python-dev
  • python-rpi.gpio
• https://code.google.com/p/raspberry-gpio-python/

Logic Level Conversion

• RPi is 3.3V.