Lambda calculation

Lambda calculation added to the loop with the conversion of an analog
value to a 0 to 5 voltage to return the lambda value.

Bench-Data-Firmware/src/main.cpp

@@ -3,9 +3,12 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 #include <Arduino.h>
 const byte interruptPin = 2;
+const byte lambdaPin = A0;
 volatile unsigned long timestamp1 = 0;
 volatile unsigned long timestamp2 = 0;
 volatile bool new_rpm = false;
+const unsigned long deltat_lambda = 100000;
+unsigned long last_lambda = 0;
 
 void interrupt(){
   unsigned long now = micros();
@@ -18,6 +21,7 @@ void setup() {
   // put your setup code here, to run once:
   Serial.begin(115200);
   pinMode(interruptPin, INPUT);
+  pinMode(lambdaPin, INPUT);
   attachInterrupt(digitalPinToInterrupt(interruptPin),interrupt,FALLING);
 }
 
@@ -27,8 +31,20 @@ void loop() {
     unsigned long deltat = timestamp1 - timestamp2;
     float rpmhz = 500000.0 / deltat;
     new_rpm = false;
+    Serial.print("Speed: ");
     Serial.println(rpmhz);
   }
+  unsigned long now = micros();
+  if (now > last_lambda + deltat_lambda){
+    float output = analogRead(lambdaPin);
+    float voltage = output / 204.6;
+    float lambda = 0.56030161*voltage + 0.43969839;
+    last_lambda = now;
+    Serial.print("Voltage: ");
+    Serial.println(voltage);
+    Serial.print("Lambda:");
+    Serial.println(lambda);
+  }
 
 }