[AVR] Arduino reading 0x00 for 1.25v ?

[Deexith Hasan]

Arduino reading 0x00 for 1.25v? it shows 0xFF for 1.00v and again switches to 0x00 for 1.25v and starts increasing......i connected pot to 5v

/*

int sensorPin = A0;    // select the input pin for the potentiometer
int ledPin = 13;      // select the pin for the LED
int sensorValue = 0;  // variable to store the value coming from the sensor

void setup() {
  // declare the ledPin as an OUTPUT:
  pinMode(ledPin, OUTPUT);  
  Serial.begin(9600);
}

void loop() {
  // read the value from the sensor:
  sensorValue = analogRead(sensorPin);
Serial.write(sensorValue);  

  // turn the ledPin on
  digitalWrite(ledPin, HIGH);  
  // stop the program for <sensorValue> milliseconds:
  delay(sensorValue);          
  // turn the ledPin off:        
  digitalWrite(ledPin, LOW);   
  // stop the program for for <sensorValue> milliseconds:
  delay(sensorValue);                  
}

but led blink rate is fine when pot is adjusted but serial port reads 0x00 for 1.25v y?

 

[ernpao]

What is your reference voltage? Remember that you are using signed int for sensorValue and that your MSB is the sign bit when you send it over the serial port, so when you send it as text, you might get something like your reading increasing from zero and then suddenly going negative. But this doesn't seem to be your problem, and I am curious why you are getting 0x00 for 1.25V (if you are using the default voltage ref on the arduino). Are you sure about your connections? Try using unsigned int for sensorValue.