I am feeding the LilyPad with a power supply (LilyPad Power Supply - DEV-08466 - SparkFun Electronics) so it should supply a Vcc of 5V. However, I believe I am getting 3.3V, because I have connected a temperature sensor, and I get the correct read of temperature in degrees when I suppose that the voltage reference of de ADC is 3.3V doing that:
read = read * (3.3/1024.0); //and I get ~22ºC (correct).
If I write: read = read * (5.0/1024.0), I get ~60ºC (degrees). It is not correct, although it should be. Why?