Yun & Compatible

Details

Written by Sonny Yu

• Multimedia

Install Webcam UVC

Install Software:

opkg update
opkg install fswebcam  

fswebcam --help
Usage: fswebcam [<options>] <filename> [[<options>] <filename> ... ]
 Options:
 -?, --help                   Display this help page and exit.
 -c, --config <filename>      Load configuration from file.
 -q, --quiet                  Hides all messages except for errors.
 -v, --verbose                Displays extra messages while capturing
     --version                Displays the version and exits.
 -l, --loop <seconds>         Run in loop mode.
 -b, --background             Run in the background.
 -o, --output <filename>      Output the log to a file.
 -d, --device <name>          Sets the source to use.
 -i, --input <number/name>    Selects the input to use.
 -t, --tuner <number>         Selects the tuner to use.
 -f, --frequency <number>     Selects the frequency use.
 -p, --palette <name>         Selects the palette format to use.
 -D, --delay <number>         Sets the pre-capture delay time. (seconds)
 -r, --resolution <size>      Sets the capture resolution.
     --fps <framerate>        Sets the capture frame rate.
 -F, --frames <number>        Sets the number of frames to capture.
 -S, --skip <number>          Sets the number of frames to skip.
     --dumpframe <filename>   Dump a raw frame frame to file.
 -s, --set <name>=<value>     Sets a control value.
     --revert                 Restores original captured image.
     --flip <direction>       Flips the image. (h, v)
     --crop <size>[,<offset>] Crop a part of the image.
     --scale <size>           Scales the image.
     --rotate <angle>         Rotates the image in right angles.
     --deinterlace            Reduces interlace artifacts.
     --invert                 Inverts the images colours.
     --greyscale              Removes colour from the image.
     --swapchannels <c1c2>    Swap channels c1 and c2.
     --no-banner              Hides the banner.
     --top-banner             Puts the banner at the top.
     --bottom-banner          Puts the banner at the bottom. (Default)
     --banner-colour <colour> Sets the banner colour. (#AARRGGBB)
     --line-colour <colour>   Sets the banner line colour.
     --text-colour <colour>   Sets the text colour.
     --font <[name][:size]>   Sets the font and/or size.
     --no-shadow              Disables the text shadow.
     --shadow                 Enables the text shadow.
     --title <text>           Sets the main title. (top left)
     --no-title               Clears the main title.
     --subtitle <text>        Sets the sub-title. (bottom left)
     --no-subtitle            Clears the sub-title.
     --timestamp <format>     Sets the timestamp format. (top right)
     --no-timestamp           Clears the timestamp.
     --gmt                    Use GMT instead of local timezone.
     --info <text>            Sets the info text. (bottom right)
     --no-info                Clears the info text.
     --underlay <PNG image>   Sets the underlay image.
     --no-underlay            Clears the underlay.
     --overlay <PNG image>    Sets the overlay image.
     --no-overlay             Clears the overlay.
     --jpeg <factor>          Outputs a JPEG image. (-1, 0 - 95)
     --png <factor>           Outputs a PNG image. (-1, 0 - 10)
     --save <filename>        Save image to file.
     --exec <command>         Execute a command and wait for it to complete.

Save image from video stream:

fswebcam  -i 0 -d v4l2:/dev/video0  --jpeg 95  --save test.jpg -S 20 -r 640x480

Save image at test.jpg, skip the first (group) frames with the -S 20.

Replace "test.jpg" with `date +"%G%m%d%H%M%S"`.jpg

It create 20140515123538.png and has 2024/05/15 12:35:38 as time stamp.

Details

Written by Sonny Yu

• Bridge Library

Arduino Yun Bridge example from IDE.

ab - Apache HTTP server benchmarking tool

http://httpd.apache.org/docs/2.2/programs/ab.html

ab -n 20 -c 1 http://192.168.0.186/arduino/analog/2/123

Concurrency Level:      1
Time taken for tests:   3.425 seconds
Complete requests:      20
Failed requests:        0
Write errors:           0
Non-2xx responses:      20
Total transferred:      2100 bytes
HTML transferred:       0 bytes
Requests per second:    5.84 [#/sec] (mean)
Time per request:       171.275 [ms] (mean)
Time per request:       171.275 [ms] (mean, across all concurrent requests)
Transfer rate:          0.60 [Kbytes/sec] received
Connection Times (ms)
             min  mean[+/-sd] median   max
Connect:        0    0   0.0      0       0
Processing:   164  171   7.9    169     192
Waiting:      153  159   6.2    156     171
Total:        164  171   7.9    169     192

171.275 [ms] (0.17 s) is average speed of bridge speed, and should meet average application's requirement.

Details

Written by Sonny Yu

• Languages and Yun

Upgrade JAVA

Create PDF file of US flag:

http://pdfjet.com/net/examples/example-01.html

Compile Example_01.java file into Example_01.class at Linux box (copy PDFjet.jar into same directory)

javac -classpath .:PDFjet.jar  Example_01.java

Test it at same box:

java -classpath .:PDFjet.jar Example_01

Copy Example_01.class file into Openwrt:

jamvm -classpath .:PDFjet.jar Example_01

Example_01.pdf is here:

https://www.dropbox.com/s/ilcxfz9i90z3j54/Example_01.pdf?dl=0