I am trying to make a circuit using a 3V3 Arduino and other modules working on 3V3, but I have a problem with an analog water sensor I need to use. The output is a voltage range is from 0.5V to 4.5V.
I think I cannot use 4.5V signal on an analog pin of an Arduino working at 3V3.
So I have a basic idea like solution. - Use a 5V step-up voltage regulator from 3V7 li-on battery for the water sensor - Then using a voltage resistor divider to convert from 5V (sensor output) to 3V3. - Then connect to the Arduino and inside make line code with a simple equation where I can recover the 5Volt value.
Will I will lose resolution doing this? Is it a bad idea?
To ensure that I will not lose resolution, what do I need to check? Maybe the minimum step voltage in the ouput of sensor? For example 5mv minimum of variation, then 5mv*voltage_divider = 3.3mv ... Then 10 bit of resolution of ADC in Arduino is enough? I got a 3.22mv resolution (3.3/1023)