Raspberry Pi and Arduino

I am putting together a data logger for the biogas generator.

I would like it networked so I don't have to go out in the cold, so will use a raspberry pi.   To make interfacing the sensors easy I will connect the Pi to an Arduino microcontroller.   This is a bit over the top as I should be able to do everything I need using the Pi's GPIO pins, but Arduino has a lot of libraries to save me programming....

To get it working I installed the following packages using:

apt-get install gcc-avr avr-libc avrdude arduino-core arduino-mk

To test it, copy the Blink.ino sketch from /usr/share/arduino/examples/01.Basics/Blink/ to a user directory.
Then create a Makefile in the same directory that has the following contents:

ARDUINO_DIR  = /usr/share/arduino
TARGET       = Blink
ARDUINO_LIBS =
BOARD_TAG    = uno
ARDUINO_PORT = /dev/ttyACM0
include /usr/share/arduino/Arduino.mk

Then just do 'make' to compile it, then upload to the arduino (in this case a Uno) using:

avrdude -F -V -p ATMEGA328P -c arduino -P/dev/ttyACM0  -U build-cli/Blink.hex

The LED on the Arduino Uno starts to blink - success!

Using Raspberry Pi as an IP Camera to Analogue Converter

I have an old-fashioned analogue TV distribution system in our house.   We use it for a video monitor for our disabled son so we can check he is ok.
The quality of the analogue camera we use is not good, but rather than getting a new analogue one, I thought I should really get into digital IP cameras.
I have had quite a nice IP camera with decent infra-red capabilities for a while (a Ycam Knight).   You can view the images and hear the audio on a computer, but it is not as useful as it working on the little portable flat panel TVs we have installed in a few rooms for the old analogue camera.

I am trying an experiment using a raspberry Pi to take the audio and video from the IP camera, and convert it to analogue signals so my old equipment can be used to view it.

What we have is:

• IP Camera connected to home network.
• Raspberry Pi connected to same network.
• Analogue video and audio signals from Pi connected to an RF modulator, which is connected to our RF distribution system.

Using this I can tune the TVs on the RF distribution system to view the Raspberry Pi output.

I set up the Pi to view the audio and video streams from the IP camera by using the omxplayer video player, which is optimised for the Pi.   I added the following to /etc/rc.local:

omxplayer rtsp://192.168.1.18/live_mpeg4.sdp &

Now when the Pi boots, it displays the video from the IP camera on its screen, which is visible to other monitors via the RF modulator.

My concern is how reliable this will be - I tried earlier in the year and the Pi crashed after a few weeks with a completely mangled root filesystem, which is no good at all.   This time I am using a new Pi and new SD card for the filesystem, so I will see how long it lasts.