Re: Ethernet shield modifies analog input (SOLVED)

Forum 2005-2010 (read only) Hardware Interfacing
1

I have connected a LM335 temperature sensor to Analog0.
It is connected to 5V, with a 2k2 resistor, and 10k potenciometer.
It is welded in a prototype board and I read 22ºC by the serial port.
If I connect the ethernet shield besides the prototypes shield, the temperature is not correct, and I read 31ºC.
Is it possible Ethernet shield interferes in the reading of analog 0?
Thanks

2

If the ethernet shield causes the 5V to drop a bit then it can influence the temperature reading on Analog 0.

try to meassure the exact voltage on the 5V pin with and without the shield attached.

3

This it is the problem
Arduino connected on USB I measure 5,016V.
When I plug the Ethernet shield I have 4,650V
I will Have to use an external power instead USB.
I did not think it could consume so much.
Thank you

4

I think on my Ethernet Shield there's two 10k pull-up resistors on analog0 and analog1. Can anybody confirm this? Why are they there? Does the Ethernet Shield need analog0 and analog1?

5

I did not think it could consume so much.

Feel the chip on the ethernet shield, it can be very warm at times.