@Zeph @daulagari Awesome thanks guys, that makes perfect sense!

@hek I was playing around with it alot last night and yes that is one of the things I did try before doing a read, but still 1023. I will confirm again when home. Any ideas of what I should be seeing for the baseline on the soil sensor?

@daulagari Yes Uno is powered via USB@5v, but the soil sensor is connected to the 3.3v regulated supply.

Working towards my sensor network and seeing a bit of an odd difference when moving from my Uno board over to the Pro Mini.

I have the Soil Sensor (3.3v powered) setup to output Analog values and am reading that via A0 pin on the Uno. The base line value I get is 682, as I add water that value drops. However when I move that sensor over to the Pro Mini (3.3v) and run the exact same sketch I get a base line value of 1023, as I add water it drops. I swapped in another Pro Mini just to rule that out and it also registers 1023 as the baseline output.

So I guess the question is, which one is correct? My initial take is that the Pro Mini is giving me bad values as it is maxed at 1023 - am I overlooking a setting on the pro mini?

I removed all other sensors including the radio and am using this bare bones sketch between the two:
<pre><code>
#define SOIL_SENSOR_ANALOG_PIN A0
void setup()
{
Serial.begin(115200);
}

void loop()
{
int soil = analogRead(SOIL_SENSOR_ANALOG_PIN);
Serial.print("SOIL:");
Serial.println(soil);

delay(1000);
}

</code></pre>

Thanks!