How to read stable lithium voltage using adc ARef arduino

Projects Programming
1

Hi there, i have wrote one code that reads a constant battery voltage irrespective of the current battery voltage. I want the system to function in such a manner that i can use the battery constant value in the sensor formula. For example:
int voltage = ((calling batt function) * Read sensor val/ 1024;

Note: The whole system will be working on a lithium battery (I am using arduino board just for prototype, if it works, ill be ussing attiny IC

My main problem is that i dont want to use analog pin to read constant battery voltage as i dont have any spare attiny pin.

Is it possible to use aref pin to get constant battery voltage.



void setup(){
  Serial.begin (115200);
}

void loop() {  
  //REFS1 AND REFS0 to 1 1 -> internal 1.1V refference
  ADMUX |= B11000000;   
  //We read A1 (MUX0)
  ADMUX |= B00000001;       
  // Start AD conversion
  ADCSRA |= B11000000;
  // Detect end-of-conversion
  while (bit_is_set(ADCSRA,ADSC));
  float val = ADCL | (ADCH << 8);
  val = val * 5.7; //Multiply by the inverse of the divider
  Serial.println(val);
}

IMG_20230213_122205_798

Please let me know if its possible to read const battery voltage using only AREf and not analog pin.

I know the if we program the AREf to be internally connected and we make any physical connections to it we can possibly damage our IC.

2

No.

Also, what happens over time when the Vbatt drops, how will Vbatt be constant if Vbatt is changing?

3

Hi, so only analog pin would work?

4

Don't believe me, give it a try for yourself and prove me right or wrong.

5

Due to their violation of forum rules, @electrogeeky has been permanently suspended from the Arduino forum.

Since there is no point in continuing this discussion, I am locking the topic.