Adding an Ethernet Shield

Attach the Ethernet shield to the Arduino by lining up the base pins so that the Ethernet jack is on top and facing the same direction as the Arduino USB jack. Reconnect the wires to the 5V and analog-in 0 (A0) pins found on the Ethernet shield just like you did when these wires were connected to the Arduino.

Do the same for the 10k ohm resistor bridging across the ground (Gnd) and A0 pins. Run your test again and check the values. In my tests, the base value being read was different compared to the Arduino without the Ethernet shield, and yours will likely reflect similar results. Since we’re more interested in the deviation from this base value than the calibration of the actual value itself, it’s important to use ...

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