Change the P and D values

pid-example/pid-example.ino

@@ -4,9 +4,9 @@ QTRSensors qtr;
 const uint8_t SensorCount = 8;
 uint16_t sensorValues[SensorCount];
 
-float Kp = 0.085; //set up the constants value
-float Ki = 0.00004;
-float Kd = 0.66;
+float Kp = 0.1; //set up the constants value
+float Ki = 0;
+float Kd = 0.5;
 int P;
 int I;
 int D;
@@ -17,8 +17,8 @@ boolean onoff = false;
 //Increasing the maxspeed can damage the motors - at a value of 255 the 6V motors will receive 7,4 V 
 const uint8_t maxspeeda = 150;
 const uint8_t maxspeedb = 150;
-const uint8_t basespeeda = 120;
-const uint8_t basespeedb = 120;
+const uint8_t basespeeda = 100;
+const uint8_t basespeedb = 100;
 
 // adding minspeed so it can reverse
 const int minspeeda = -150;
@@ -74,7 +74,7 @@ void calibration() {
 void loop() {
   if(digitalRead(buttonstart) == HIGH) {
     onoff =! onoff;
-    if(onoff = true) {
+    if(onoff == true) {
       delay(1000);//a delay when the robot starts
     }
     else {
@@ -114,16 +114,23 @@ void speedcontrol(int mota, int motb) {
     forward_brake(mota, motb);
   }
   if (mota < 0 && motb >= 0) {
-    //dreapta
+    
     mota = 0 - mota;
     right_brake(mota, motb);
      
   }
   if (mota >= 0 && motb < 0) {
-    //stanga
+    
     motb = 0 - motb;
     left_brake(mota, motb);
   }
+  if (mota < 0 && motb < 0) {
+  // both reversing — clamp or handle as a pivot/brake depending on your track
+  mota = -mota;
+  motb = -motb;
+  // e.g. sharp spin: one motor forward, one back
+  right_brake(mota, motb); // or left_brake, or forward_brake(0,0) to just brake
+  }
 }
 
 void PID_control() {