hey
this my code for arduino to read o2 sensor with pc monitor and led output
try!!!!
    int analogInPin = A0; // Analog input pin that the LAMBDA is attached to
                     //const int analogOutPin = 9; // Analog output pin
        int sensorValue = 0; // value read from LAMBDA
        float outputValue = 0; // value output mV
        
        int led1=13;    // afr 12.5 0.86 
        int led2=12;    // afr 13.2 0.90
        int led3=11;    // afr 13.8 0.93
        int led4=10;    // afr 14.3 0.97
        int led5=9;     // afr 14.4 0.98
        int led6=8;     // afr 14.7 1 STACHEO
        int led7=7;     // afr 1.25 18 
void setup() {
          pinMode(led1,OUTPUT); //ROUGE
          pinMode(led2,OUTPUT); //ROUGE
          pinMode(led3,OUTPUT); //ORANGE
          pinMode(led4,OUTPUT); //ORANGE
          pinMode(led5,OUTPUT); //VERTE
          pinMode(led6,OUTPUT); //BLEU
          pinMode(led7,OUTPUT); //BLANCHE
          
                             
        Serial.begin(9600);   // initialize serial communications at 9600 bps:
         Serial.println(" HONDA Lambda");
       
                     }
void loop() {
 
        // read the analog in value:
        sensorValue = analogRead(A0);
        // map it to the range of the analog out:
        outputValue = sensorValue*4.88;
        //outputValue = map(sensorValue, 0, 1023, 0, 5000); //conversion de la valeur lue en tension en V
        
if (outputValue > 945) Serial.print(" Lambda= 0.80 "),Serial.print(" AFR 12 "),digitalWrite (led1, HIGH),digitalWrite (led2, HIGH);
 else digitalWrite (led1, LOW),digitalWrite (led2, LOW);
if (outputValue > 900 && outputValue <= 945) Serial.print(" Lambda= 0.85 MAX POWER"), digitalWrite (led1, HIGH);
 else digitalWrite (led1, LOW);
 
if (outputValue > 855 && outputValue <= 900) Serial.print(" Lambda= 0.90 RICH"),digitalWrite (led2, HIGH);
 else digitalWrite (led2, LOW);
 
if (outputValue > 810 && outputValue <= 855) Serial.print(" Lambda= 0.93 ++Rich"),digitalWrite (led3, HIGH);
 else digitalWrite (led3, LOW);
 
if (outputValue > 540 && outputValue <= 810) Serial.print(" Lambda= 0.97 +Rich"),digitalWrite (led4, HIGH);
 else digitalWrite (led4, LOW);
 
if (outputValue > 225 && outputValue <= 540) Serial.print(" Lambda= 0.98 Low Rich"),digitalWrite (led5, HIGH);
 else digitalWrite (led5, LOW);
 
if (outputValue > 180 && outputValue <= 225) Serial.print(" Lambda= 1  STACHEO 14.7 "),digitalWrite (led6,OUTPUT);
 else digitalWrite(led6,LOW);
if (outputValue > 135 && outputValue <= 180) Serial.print(" Lambda= 1.02 learn");
if (outputValue > 90 && outputValue <= 135) Serial.print(" Lambda= 1.04 LEARN");
if (outputValue > 45 && outputValue <= 90) Serial.print(" Lambda= 1.15");
 
if (outputValue <= 45) Serial.print(" Lambda = 1.25 "),digitalWrite (led7, HIGH);
 else digitalWrite (led7, LOW);
       
        Serial.print(" (mV): ");
        Serial.println(outputValue);
        delay(200);
			
			
			
									
									
						