I'm just getting used to my Arduino board and I'm trying to measure the voltage of the cell, so that ultimately I can flash an LED on my project when the batteries need replacing.
I followed this guide: http://arduinotronics.blogspot.co.uk/2011/03/monitoring-voltage-of-dc-battery-supply.html and am sure that I've wired everything correctly. when the battery is switched on, the output values in the console are roughly -1910.00. Any idea what I'm doing wrong? From the calculations in that example, should this be returning values around the 5 mark if wired correctly?
Also, at what kind of voltage drop would the board stop working?
Any help would be appreciated. Thank you.