Difference between revisions of "Raspberry Pi - Week 4"

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*Ran a simple python script to synthesize speech ([[Raspberry_Pi_-_Week_3#Festival_example | example]])
 
*Ran a simple python script to synthesize speech ([[Raspberry_Pi_-_Week_3#Festival_example | example]])
 
*Another python tutorial: [http://learnpythonthehardway.org/book/ Learn Python the Hard Way]
 
*Another python tutorial: [http://learnpythonthehardway.org/book/ Learn Python the Hard Way]
 +
== Video Playback ==
 +
*[https://github.com/huceke/omxplayer 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.
 +
*Try it out.
 +
*Copy a movie file to your raspberry pi using scp. The movie needs to be .mp4 format.
 +
**you can transcode with ffmpeg:
 +
**<code>ffmpeg -i mouse_brain.wmv mouse_brain.mp4</code>
 +
*run omxplayer:
 +
**<code>omxplayer ~/Movies/mouse_brain.mp4</code>
 +
*You can control playback with a number of hotkeys:
 +
**http://elinux.org/Omxplayer#Hotkeys
 +
**Try these, and notice the responsiveness of the system. Is there any noticable delay?
 +
 +
===ffmpeg===
 +
*Install this on your computer, not the raspberry pi.
 +
**install homebrew
 +
**<code>brew install ffmpeg</code>
 +
*using ffmpeg to transcode a video file:
 +
**<code>ffmpeg -i ~/Movies/dogkiss.mov dogkiss.mp4</code>
  
−
== Video Playback ==
 
 
== Scripting Video Playback ==
 
== Scripting Video Playback ==
 +
[http://wiki.roberttwomey.com/images/a/ad/Video_loop.tar video_loop.tar]
 +
*We can send the hotkey controls via STDIN in python:
 +
**http://stackoverflow.com/questions/12755968/sending-arrow-keys-to-popen
 +
*shell script to play a directory of files. (good at corporate conventions)
 +
**http://www.cenolan.com/2013/03/looping-video-playlist-omxplayer-raspberry-pi/
 +
 
== GPIO ==
 
== GPIO ==
 +
*What are the pins?
 +
**http://elinux.org/RPi_Low-level_peripherals
 +
*Handy printable reference
 +
**Raspberry Leaf - http://www.doctormonk.com/2013/02/raspberry-pi-and-breadboard-raspberry.html
 +
*Other headers, not yet populated
 +
**P5, etc...
 +
===Note on voltage Levels===
 +
*RPi is 3.3V.
 
*pin over-voltage protection circuits - http://elinux.org/RPi_Tutorial_EGHS:GPIO_Protection_Circuits
 
*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/
+
==Tutorials==
−
**uses wiringPI, command line tool, for ex:<code>gpio</code>
+
*Single LED-https://projects.drogon.net/raspberry-pi/gpio-examples/tux-crossing/gpio-examples-1-a-single-led/
−
**installed using git - https://projects.drogon.net/raspberry-pi/wiringpi/download-and-install/
+
*GPIO examples-https://projects.drogon.net/raspberry-pi/gpio-examples/
−
===through python===
+
*LCD interface https://projects.drogon.net/raspberry-pi/gpio-examples/lcd-interface/
−
*follow adafruit - http://learn.adafruit.com/adafruits-raspberry-pi-lesson-4-gpio-setup/overview
+
 
−
**Rpi.GPIO -  
+
===using GPIO with python===
−
**requires python-dev
 
−
**python-rpi.gpio
 
 
*https://code.google.com/p/raspberry-gpio-python/
 
*https://code.google.com/p/raspberry-gpio-python/
−
===Logic Level Conversion===
+
**<code>sudo apt-get update</code>
−
*RPi is 3.3V.
+
**<code>sudo apt-get install python-dev</code>
 +
**<code>sudo apt-get install python-rpi.gpio</code>
 +
*Examples - https://code.google.com/p/raspberry-gpio-python/wiki/Examples
 +
**Basic Usage
 +
**Inputs
 +
**Outputs
 +
**PWM
 +
*adafruit - http://learn.adafruit.com/adafruits-raspberry-pi-lesson-4-gpio-setup/overview

Latest revision as of 15:09, 26 April 2013

<<< 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.
  • Try it out.
  • Copy a movie file to your raspberry pi using scp. The movie needs to be .mp4 format.
    • you can transcode with ffmpeg:
    • ffmpeg -i mouse_brain.wmv mouse_brain.mp4
  • run omxplayer:
    • omxplayer ~/Movies/mouse_brain.mp4
  • You can control playback with a number of hotkeys:

ffmpeg

  • Install this on your computer, not the raspberry pi.
    • install homebrew
    • brew install ffmpeg
  • using ffmpeg to transcode a video file:
    • ffmpeg -i ~/Movies/dogkiss.mov dogkiss.mp4

Scripting Video Playback

video_loop.tar

GPIO

Note on voltage Levels

Tutorials

using GPIO with python

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