Hardware

My original plan was to have the AVR board in the house and have a run of 60-80′ out to the sensors in the lake.  This didn’t work as the signal from the sensor was too weak to be read by the AVR.  I used a 9′ length of Cat5 cable for the sensor.  I used shrink tube on the 3 leads and a larger shrink tube to cover from the sensor to a few inches up the cable.  I then painted it over with epoxy.  I used the same epoxy as rod builders use on the rod guides as I had this type from my fly rod building.  I placed the circuit board into a plastic box and zap-strapped it to a fence post by the lake.  I ran approx 110′ of Cat5 cable from the house to the circuit board.  I used the orange & green pairs for the network and the blue & brown for the “home-brew” 5v POE.  To power the board I used a 5v phone charger “wall wart”

The AVR/Ethernet Web Server

Closeup of Cat5 connector.  Ethernet uses pins 1,2,3 & 6

The blue and brown pairs are used for POE

Prototype section of the board showing the air temp sensor and pullup resistor etc

I an going to move the sensor off the board to get a more accurate reading.

Software

I changed the setup of the AVR web server to remove the “remote switch control” option as I didn’t need it.  I also changed the “sensor 0″ and “sensor 1″ labels to lake and air temp.  However currently I am not using the AVR’s built in web server to display the lake temperature, rather I am using a windows PC to pull this data into the webcam image.

I have an old Windows 98 PC running the webcam and weather station at the cabin.  I installed UnxUtils for DOS/Windows and also a Unix cron clone.  Cron runs a DOS batch file every 5 minutes.  The batch file uses “wget” to pull the current lake temperature from the AVR web server and writes it to a text file on the Windows PC.  When the webcam captures an image it looks at this text file and uses the data in it to display the temperature on the captured image.  I capture the temperature in both Celsius and Fahrenheit.

I have to thank Guido Socher for all his help with the AVR ethernet web server – check out Tux Graphics for his great electronic and AVR kits.