Sunday, September 1, 2013

Raspberry Pi Camera board Test

  1. Raspberry PI Camera module over WiFiI had been interested in the Raspberry Pi Camera board and finally decided to spend money on the RPi Camera.
    It is actually quite nice and useful, and I am very happy with this, especially I can now try using this instead of USB camera :)
    Here is a note for the quick test.
  2. Setups
    There is nicely documented site in the raspberrypi.org, and this page helped me a lot to bring up the board quickly.  (Thank you!)

    http://www.raspberrypi.org/camera#

    As this site describes, I just used NETCAT and MPLAYER.


  3. Start Streaming!

    TX (RPi)
    raspivid -t 999999 -o - | nc [insert the IP address of the client] 5001

    RX (Windows 7)

    [Path to nc.exe]\nc.exe -L -p 5001 | [Path to mplayer.exe]\mplayer.exe -fps 31 -cache 1024 -

    I was actually able to stream the 1080p@30 video quite nicely.

    This is really interesting...


  4. Using battery pack...
    After the streaming check, I was curious it would work with the battery pack that I was using for RC Car project.
    Then, let's try..
    The battery pack is capable to output DC 5V < 1200mA.
    It seems like Raspberry Pi consumes about 700mA @5V.
    Not sure the how much the camera draws the current, but I read some people saying around 250mA.
    Maybe it would be worth trying the external battery!
    ...

    The result was interesting, and using above same resolution, the video was so unstable. It sometimes stop working.
    (I did not debug much but at least WiFi process was killed.)
    Also, I saw strange lines in the video image.
    I needed to lower the resolution to around 640 x 480 to make it work stable at 30Hz.


    TX (RPi)
    raspivid -t 999999 -w 640 -h 480 -o - | nc [insert the IP address of the client] 5001

    Hmm... this battery was working fine with RPi using USB camera though...

    Notes:
    
    1.  How to take picture/video using camera board
         Picture (JPEG)


           $ raspistill -o filename.jpg
         
          Video (for 5 seconds, h264)


           $ raspivid -t 5000 -o filename.h264

    2. How to transfer the file using NETCAT
         TX(RPi)
       $ nc [insert the IP address of the host(PC)] 5001 > filename


         RX(PC)
       $ nc -l 5001 < filename

Hardware:
    Raspberry Pi
    Raspberry Pi Camera Board
    EW-7781Uh WiFi dongle
    Concept Green Battery Portable Charger

   
Summary:
    WiFi video streaming was tested using Raspberry Pi camera board.

    RPi CPU usage was less than 40% for nc and about 6% for raspivid (top command)
    When I tried the battery pack, the video was so unstable...

    It could be the power line issue, and I should probably measure the current and voltage next time.

Reference:    
    http://www.raspberrypi.org/camera#
    http://en.wikipedia.org/wiki/Raspberry_Pi

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