Servo Control error

Other Hardware Motors, Mechanics, Power and CNC
1

I am making my own coil metal detector and have made the serial monitor say Metal detected if it detects metal and no metal if not. I want to make a servo motor turn when it says metal detected and for that the servo has to read the serial monitor to see when it says metal detected. I want to make an if statement basically saying if the serial monitor says metal detected turn the servo 90 degrees. How do I do that? I am new to programming and would appreciate if you could help me.

#include <Servo.h>
Servo myServo;
int servoPin=9;
int servoPos=180;

const byte npulse = 12; // number of pulses to charge the capacitor before each measurement
 
const byte pin_pulse = A0; // sends pulses to charge the capacitor (can be a digital pin)
const byte pin_cap  = A1; // measures the capacitor charge
const byte pin_LED = 12; // LED that turns on when metal is detected
 
void setup() {
  Serial.begin(9600);
  myServo.attach(servoPin);
  pinMode(pin_pulse, OUTPUT);
  digitalWrite(pin_pulse, LOW);
  pinMode(pin_cap, INPUT);
  pinMode(pin_LED, OUTPUT);
  digitalWrite(pin_LED, LOW);
}
 
const int nmeas = 256; //measurements to take
long int sumsum = 0; //running sum of 64 sums
long int skip = 0; //number of skipped sums
long int diff = 0;      //difference between sum and avgsum
long int flash_period = 0; //period (in ms)
long unsigned int prev_flash = 0; //time stamp of previous flash
 
void loop() {

  int minval = 2000;
  int maxval = 0;
 
  //perform measurement
  long unsigned int sum = 0;
  for (int imeas = 0; imeas < nmeas + 2; imeas++) {
    //reset the capacitor
    pinMode(pin_cap, OUTPUT);
    digitalWrite(pin_cap, LOW);
    delayMicroseconds(20);
    pinMode(pin_cap, INPUT);
    //apply pulses
    for (int ipulse = 0; ipulse < npulse; ipulse++) {
      digitalWrite(pin_pulse, HIGH); //takes 3.5 microseconds
      delayMicroseconds(3);
      digitalWrite(pin_pulse, LOW); //takes 3.5 microseconds
      delayMicroseconds(3);
    }
    //read the charge on the capacitor
    int val = analogRead(pin_cap); //takes 13x8=104 microseconds
    minval = min(val, minval);
    maxval = max(val, maxval);
    sum += val;
 
    //determine if LEDs should be on or off
    long unsigned int timestamp = millis();
    byte ledstat = 0;
    if (timestamp < prev_flash +12) {
      if (diff > 0)ledstat = 1;
      if (diff < 0)ledstat = 2;
    }
    if (timestamp > prev_flash + flash_period) {
      if (diff > 0)ledstat = 1;
      if (diff < 0)ledstat = 2;
      prev_flash = timestamp;
    }
    if (flash_period > 1000)ledstat = 0;
 
    //switch the LEDs to this setting
    if (ledstat == 0) {
      digitalWrite(pin_LED, LOW);
      Serial.println("No metal");
    }
    if (ledstat == 1) {
      digitalWrite(pin_LED, LOW);
      Serial.println("No metal");
    }
    if (ledstat == 2) {
      digitalWrite(pin_LED, HIGH);
      Serial.println("Metal detected");
    }
    if Serial.print=("Metal detected")
    myServo.write(servoPos);
    
  }
 
  //subtract minimum and maximum value to remove spikes
  sum -= minval; sum -= maxval;
 
  //process
  if (sumsum == 0) sumsum = sum << 6; //set sumsum to expected value
  long int avgsum = (sumsum + 32) >> 6;
  diff = sum - avgsum;
  if (abs(diff)<avgsum >> 10) {   //adjust for small changes
    sumsum = sumsum + sum - avgsum;
    skip = 0;
  } else {
    skip++;
  }
  if (skip > 64) {  // break off in case of prolonged skipping
    sumsum = sum << 6;
    skip = 0;
  }
 
  // one permille change = 2 ticks/s
  if (diff == 0) flash_period = 1000000;
  else flash_period = avgsum / (2 * abs(diff));
}

When I changed a part of the code to this

if (ledstat == 2) {
      digitalWrite(pin_LED, HIGH);
      Serial.println("Metal detected");
      myServo.write(90);
      delay(3000);
      myServo.write(0);

It just says Metal detected forever and the led stays on and doesn't turn off and says No metal.

How do I fix this???

2 
if (ledstat == 2) 
    {
      digitalWrite(pin_LED, HIGH);
      Serial.println("Metal detected");
    }
    if Serial.print = ("Metal detected")
                        myServo.write(servoPos);

====> Try the following:

if (ledstat == 2) 
    {
      digitalWrite(pin_LED, HIGH);
      Serial.println("Metal detected");
      myServo.write(servoPos);
    }
3

This is a continuation of this thread. Why did you start a new thread.

4

Because My science project is due today and I ran into some last minute problems and need answers fast because i am a doofus and don't know what I am doing.

5

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