The pulse measured is from a pre-paid electricity meter. The highest frequency possible is about 4Hz, and the message size is 6 bytes on every pulse. The only thing connected to the Arduino is a 100K LDR and and a 100K resistor to offset the LDR voltage. The integrated LED on pin 13 is flashed with every pulse. Other than that, nothing is connected.
The exact same components are attached to the Duemilanove though.
Does anyone do something like data acquisition with an Uno that can confirm an uptime of months?