Analog Inputs and Ethernet Shield

Forum 2005-2010 (read only) Hardware Troubleshooting
1

I am a newb to the arduino. I have a Duemilanove with an ethernet shield v1.2 and a Wiznet WIZ811MJ. Ran the Ethernet webserver sample code that's built into the IDE. When I run it and go to the ardunio IP the program prints out the values of the 4 analog pins. What I don't understand is every time I refresh the page, the values of the analog pins change, they range between 200 to 300. Shouldn't they all be at zero, or close to it. Is the Ethernet shield putting voltage on these.

Also what digital pins are used by the Ethernet shield and which ones are free for me to use?

--Scott

2

What have you got connected to the analogue input pins?

3

When the analog inputs aren't connected to anything, they give random numbers.

4

The pins are floating and measuring noise pickup. If you tie them to ground either directly or through a resistor they will read 0 or very close to it.

I believe the ethernet shield uses D10, D11, D12, & D13

5

Thanks, that helps.