BCD LCD + CC2630

    This is a demo, how to transmit image data to a BCD LCD panel. This system includes:
1) PC base software : It reads image files, then convert it to black-white image format, finally, send the image data to CC2630 control board.
2) CC2630 zigbee coordinator with USB  connector : This device connect to a PC, it will communicate with PC base software by USB virtual COM port.
3) CC2630 zigbee  device : This device is powered by battery, it will receive image data from CC2630 zigbee coordinator, then display the image on the BCD LCD panel.

Pidora - Use Raspberry Pi as an IP Camera (mjpg-streamer)

Introduction

    This is a practice, I use Raspberry Pi (Raspberry Pi Model B+ not work?) as an IP camera.


Prepare Hardwares

Raspberry Pi
P5V04AA (SUNNY CMOS camera module, image sensor is OV5647)


Install Packages (by root user)

# yum install 'raspberrypi-vc-*'

# vcgencmd get_camera
supported=1 detected=1 <== it means that camera has worked!


# yum install libjpeg-turbo-devel

# yum install libv4l-devel

# ln -s /usr/include/linux/videodev2.h /usr/include/linux/videodev.h

# cd /usr/src
# git clone https://github.com/jacksonliam/mjpg-streamer.git ./mjpg-streamer-git
# cd mjpg-streamer-git/mjpg-streamer-experimental
# make clean all

# cp mjpg_streamer /usr/local/bin
# cp input_raspicam.so output_http.so /usr/local/lib/.
# cp -R www /usr/local/www


Run mjpeg streamer server

# LD_LIBRARY_PATH=/usr/local/lib mjpg_streamer -i "input_raspicam.so -fps 15 -q 50 -x 640 -y 480" -o "output_http.so -w /usr/local/www"
    It will display message as following:
 i: fps.............: 15
 i: resolution........: 640 x 480
 i: camera parameters..............:

Sharpness 0, Contrast 0, Brightness 50
Saturation 0, ISO 400, Video Stabilisation No, Exposure compensation 0
Exposure Mode 'auto', AWB Mode 'auto', Image Effect 'none'
Metering Mode 'average', Colour Effect Enabled No with U = 128, V = 128
Rotation 0, hflip No, vflip No
 o: www-folder-path...: /usr/local/www/
 o: HTTP TCP port.....: 8080
 o: username:password.: disabled
 o: commands..........: enabled
 i: Starting Camera


Test

View on your browser by URL:

http://{IP address}:8080

Reference

Raspberry Pi camera board video streaming

Monitor IP camera on PC by RTSP

    This test program is an extension of my previous test program (article "Use USB camera as barcode reader - image resolution is 1280 x 720"), I replace the USB communication interface by RTSP communication interface.

    The RTSP communication implements live555 library, all my programming environment is done by VC++.

    Except the capturing image from IP camera, some image processing (image filters - gray, noise, negative, contour, histogram) is done, and image analysis (OCR, optical character recognition) is tested, too.

Python - GPIO control on Pidora for Raspberry Pi Model B+

Introduction

On the Raspberry Pi Model B+ board, there are many GPIO ports, here we make a simple test, and try to understand how to control GPIO ports by python?


Concept of hardware control

Generally, an IO port of an IC (e.g. MCU, ARM, GPU) could be have multiple functions. So, when we write a control program to control these IO ports, it can be in 3 steps:
1) Configure the hardware function
2) Execute the control function
3) Release the hardware function

Install RPi.GPIO package

There are many libraries(such as RPi.GPIO, WiringPi, or pigpio library) can do the GPIO control. At here, we are using RPi.GPIO library.

Usually, read or write GPIO, the user must be root.

Install packages:
# yum update
# yum install python-setuptools
# yum install python-pip
# easy_install pyerial   <== serial communication package
# yum install python-devel
# pip install RPi.GPIO   <== GPIO control package
# pip install cython
# reboot


Write a GPIO input/output control program

We write a simple test program to test the GPIO functions. We define functions:
GPIO12 (pin32) - output pin
GPIO13 (pin33) - input pin

Example code:
====================================================================
import time
import RPi.GPIO as GPIO
import kbhit # read keybard value, source code is at bottom

def InputEvent(channel):
     # got input event
     print "[INPUT] Got input event."

if __name__ == '__main__':
    # configure the GPIO hardware condition
    GPIO.setmode(GPIO.BCM)
    GPIO.setup(12, GPIO.OUT) # GPIO12, pin32, output control
    GPIO.setup(13, GPIO.IN, pull_up_down=GPIO.PUD_UP) # GPIO13, pin33, input control
    GPIO.add_event_detect(13, GPIO.FALLING, callback=InputEvent)

    kb = KBHit()

    bPin32On = False

    while True:
        # if the 'ESC' key is pressed, stop the while loop
        if kb.kbhit():
            c = kb.getch()
            if ord(c) == 27: # ESC 
                break        # Set On/Off pin32
        print "[OUTPUT] Set output event."
        if bPin32On: # True
            GPIO.output(12,GPIO.HIGH)
        else: # False
            GPIO.output(12,GPIO.LOW)
        # switch signal
        bPin32On = not bPin32On 
        time.sleep(2.0)

    kb.set_normal_term()

    # release the hardware configuration 
    GPIO.cleanup()
====================================================================


Get the keyboard value

The KBHit class is used to monitor the non-blocking keyboard event.
Source code:
====================================================================
import os

# Windows
if os.name == 'nt':
    import msvcrt
# Posix (Linux, OS X)
else:
    import sys
    import termios
    import atexit
    from select import select

class KBHit:     def __init__(self):
    '''Creates a KBHit object that you can call to do various keyboard things.
    '''
    if os.name == 'nt':
        pass
    else: 
        # Save the terminal settings
        self.fd = sys.stdin.fileno() 
        self.new_term = termios.tcgetattr(self.fd)
        self.old_term = termios.tcgetattr(self.fd)
        # New terminal setting unbuffered
        self.new_term[3] = (self.new_term[3] & ~termios.ICANON & ~termios.ECHO) 
        termios.tcsetattr(self.fd, termios.TCSAFLUSH, self.new_term) 
        # Support normal-terminal reset at exit
        atexit.register(self.set_normal_term)

    def set_normal_term(self):
        ''' Resets to normal terminal. On Windows this is a no-op.          ''' 
        if os.name == 'nt': 
            pass 
        else:
            termios.tcsetattr(self.fd, termios.TCSAFLUSH, self.old_term)

    def set_curses_term(self):
        '''          switch to unbuffered terminal 
        :return:
        ''' 
        if os.name == 'nt':
            pass
        else:
            termios.tcsetattr(self.fd, termios.TCSAFLUSH, self.new_term)

    def putch(self, ch):
        if os.name == 'nt':
            msvcrt.putch(ch.encode('ascii', 'ignore'))
        else:
            sys.stdout.write(ch)

    def getch(self):
        ''' Returns a keyboard character after kbhit() has been called.
          Should not be called in the same program as getarrow(). 
        '''
        s = ''

        if os.name == 'nt':
            return msvcrt.getch().decode('utf-8')
        else:
            return sys.stdin.read(1)

    def getche(self): 
        ch = self.getch()
        self.putch(ch) 
        return ch

    def getarrow(self):
        ''' Returns an arrow-key code after kbhit() has been called. Codes are
        0 : up
        1 : right
        2 : down 
        3 : left
        Should not be called in the same program as getch().
        '''

        if os.name == 'nt':
            msvcrt.getch() # skip 0xE0 
            c = msvcrt.getch()
            vals = [72, 77, 80, 75]
        else:
            c = sys.stdin.read(3)[2]
            vals = [65, 67, 66, 68]

        return vals.index(ord(c.decode('utf-8')))

    def kbhit(self):
        ''' Returns True if keyboard character was hit, False otherwise.
        '''
        if os.name == 'nt':
            return msvcrt.kbhit()
        else:
            dr,dw,de = select([sys.stdin], [], [], 0)
        return dr != []
====================================================================


Conclusion

Python is a powerful programming tool, it can satisfy the most requirements of our daily tasks. If you want to get the high performance of a program, assember, C, or C++ would be the best choice.


Reference
RPi.GPIO
Python.org

Run Pidora on Raspberry Pi Model B+

Inroduction

Pidora is a Fedora Remix optimized for the Raspberry Pi computer. So, it is a good candidate choice for implementation if you are familiar with Fedora.
Here, I present the installation steps of installing Pidora 20 on Raspberry Pi Model B+ board. All the preparing works are done on Fedora 20.


Download image file

http://pidora.ca/pidora/releases/20/images/Pidora-2014-R3.zip


Write image file to SD card

dd (convert and copy a file) is a command-line utility for Unix/Linux, I use dd to write Pidora-2014-R3.img file to SD card.

# unzip Pidora-2014-R3.zip (uncompress to Pidora-2014-R3.img)
# dd if=Pidora-2014-R3.img of=/dev/sdb bs=4M (The SD card is at /dev/sdb)

On Windows, you can write image file by Win32 Disk Image.

After the dd command has done, remove the SD card and plug into socket, again. It would be mounted at 2 path:
/run/media/{user}/BOOT
/run/media/{user}/rootfs



Extra works

The default running job is display X window on TV/Monitor via HDMI interface, and the default network is using dynamic IP address. If you want to run it on console mode with static IP address, there is some extra work that you should do.

# vi /run/media/{user}/BOOT/headless
IPADDR=192.168.1.19         # the static IP address
NETMASK=255.255.255.0
GATEWAY=192.168.1.1
RESIZE         # extend the SD card size to its real size
SWAP=512

# vi /run/media/{user}/rootfs/etc/sysconfig/network-scripts/ifcfg-Wired_connection_1
TYPE=Ethernet
BOOTPROTO=none
IPADDR0=192.168.1.19    # the static IP address
PREFIX0=24
GATEWAY0=192.168.1.1
DNS1=168.95.1.1
DNS2=168.95.192.1
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes
IPV6_FAILURE_FATAL=no
NAME="Wired connection 1"
UUID=b2df4348-a75e-4e80-ab3f-470154e1fc8c
ONBOOT=yes


Install/Update application packages

Some of my works is done by python with serial communication, therefore, I have to install some packages:


# yum update
# yum install python-setuptools
# yum install python-pip
# easy_install pyerial   <== serial communication package
# yum install python-devel
# yum install libxml2 libxslt
# yum install libxslt-devel
# pip install RPi.GPIO   <== GPIO control package
# pip install cython
# reboot


Conclusion

Except the write image to SD card process and disk partition policy is different from Fedora on PC, other works are same as you work on Fedora environment.


Reference

Pidroa official site
Win32 Disk Image

Use USB camera as barcode reader - image resolution is 1280 x 720

    This is a test, I use my USB camera (1280x720 pixels) to analyze barcode informaiton. It works!

    This test program implements DirectShow filters, capture USB camera image by UVC(USB video class) interface.

Porting Android 4.0.1 on BeagleBoard Rev C3

    I try to port android 4.0.1 on BeagleBoard Rev C3, it works!
The video of system booting is on youtube:

    I download the android source code from site: https://bitbucket.org/sola/android_manifest, here, Android 4.0 on BeagleBoard and Beagleboard-xM, is a good tutorial of building linux kernel, android, and root file system.

    The BeagleBoard Rev C3 (CPU is OMAP3530 includes ARM Cortex A8).

    The locked screen.

    The apps list.

    OS kernel version.