So this is my basic circuit. Three voltage dividers: one 10k pot, 2 thermistors. Fan driver circuit using TIP120 (currently just driving an LED from the 3.3v source). Board is a Leonardo clone, circuits.io only had the Uno in their library. Edit: circuit is now more simplified.
Schematic:
reality:
When I adjust the pot, the ADC value of airPinValue
changes, regardless of which analog input it is connected to. meatPinValue
does not change. Swapping the inputs that airTempPin
and meatTempPin
are assigned to has no effect, airTempPin
changes the same. Physically swapping the thermistors has no effect, nor does switching which input they connect to.
Code:
#define potPin A0
#define airTempPin A5
int potValue = 0;
int airPinValue = 0;
int i = 0;
void setup() {
Serial.begin(9600);
}
void loop() {
i++;
potValue = analogRead(potPin);
airPinValue = analogRead(airTempPin);
if (i == 2000) {
Serial.print(potValue);
Serial.print(",");
Serial.println(airPinValue);
i = 0;
}
}
EDIT: much simplified code
EDIT v2.0 : I have now swapped out the board for an official Uno, as well as swapped everything to a different breadboard and a different Leonardo, with no change in behavior.
EDIT v3 : Corrected code sample. I have also dropped my DMM onto this, reading from the 5v rail to the voltage going to A2. With the pot set to 0 I see 2.401v from the divider, pot to max, same voltage, 2.401v.
EDIT v4: with only the pot and airTemp hooked up, still happens. Further DMM probing actually shows that this only happens when the pot and thermistor are both hooked up to the arduino. If either one is disconnected, the voltage being read by airTempPin
is stable/correct. Once both are hooked up to the analog pins on the arduino, that's when the voltage at airTempPin
goes off...
Also update diagram, pic, and code to match what I'm currently testing with.
EDIT v5 : This is some sort of analog bleed between the analog input ports. Not really sure how I can combat this :\
potValue,airPinValue,meatPinValue 0,459,484 457,482,484 1023,515,484
- oh, apparently can't have linebreaks in comments. This is a small sample showing the values of the pins