Tyhterington

Raspberry Pi – Building the Basic Streamer

1. Install build dependencies

You need to be connected to the internet. The following command installs the three libraries that MJPG-Streamer uses:

$ sudo apt-get install libjpeg8-dev imagemagick libv4l-dev

2. Add missing videodev.h

The videodev.h header file that MJPG-Streamer needs has been replaced with a videodev2.h. To make MJPG-Streamer happy you have to create a symbolic link:

$ sudo ln -s /usr/include/linux/videodev2.h /usr/include/linux/videodev.h

3. Download MJPG-Streamer

The source code for MJPG-Streamer is available at sourceforge.net, but it is tricky to find the direct download link:

$ wget http://sourceforge.net/code-snapshots/svn/m/mj/mjpg-streamer/code/mjpg-streamer-code-182.zip

4. Unzip the MJPG-Streamer source code

The source code download is a compressed zip file. Put the file in your home directory (or a temporary folder, if you prefer) and run the following to extract the files:

$ unzip mjpg-streamer-code-182.zip

5. Build MJPG-Streamer

MJPG-Streamer comes with several plugins – we will build them all

$ cd mjpg-streamer-code-182/mjpg-streamer
$ make

6. Install MJPG-Streamer

Copy the required files to the install dirs. The following commands copy all the needed files into system directories:

$ sudo cp mjpg_streamer /usr/local/bin
$ sudo cp output_http.so input_file.so /usr/local/lib/
$ sudo cp -R www /usr/local/www

7. Start the camera

We are almost there. Now it is time to start the camera module:

$ mkdir /tmp/stream
$ raspistill --nopreview -w 640 -h 480 -q 5 -o /tmp/stream/pic.jpg -tl 100 -t 9999999 -th 0:0:0 &

Of course, you can use different options to raspistill if you like.

8. Start MJPG-Streamer

The camera is now writing images, so all that is left is to start MJPG-Streamer:

LD_LIBRARY_PATH=/usr/local/lib mjpg_streamer -i "input_file.so -f /tmp/stream -n pic.jpg" -o "output_http.so -w /usr/local/www"

9. Watch the Stream!

Now you can connect with your web browser and watch the stream live. If you want to watch from within the same Raspberry Pi you can enter http://localhost:8080 in the browser’s address bar. If you want to watch from another computer in your network use http://<IP-address&gt;:8080.

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Processing – Knowledge Test

Use this code in processing – the challenge is to make two lines – vertical and make the vertical one move at twice the speed


float y = 100;

// The statements in the setup() function 
// execute once when the program begins

// Note that height and width is set by processing - you dont have to declare them

void setup() { 

  size(640, 360);  // Size must be the first statement
  stroke(255);     // Set line drawing color to white
  frameRate(30);

}
// The statements in draw() are executed until the 
// program is stopped. Each statement is executed in 
// sequence and after the last line is read, the first 
// line is executed again.
void draw() { 
  background(0);   // Set the background to black
  y = y - 1; 
  if (y < 0) { 
    y = height; 
  } 
  
    line(0, y, width, y);  
}