Why is the loop() stopping?

Question

I would like to move my servo motor (SM-S2309S) between random angles. In order to do so, I used this simple code:

#include <Servo.h>
Servo servoMain; // Define our Servo

// SM-S2309S angular speed
float speed = 0.12/60;

void move(int from, int to)
{
  // initiate the move to the new angle
  servoMain.write(to);
  // wait for the movement to actually happen over the actual angle to move through
  delay(1000 * speed * int(from-to));
}

void setup()
{
   servoMain.attach(10); // servo on digital pin 10
   Serial.begin(115200);
   // move to center as a start
   servoMain.write(90);
   delay(1000);
}

void loop()
{
  // the previous angle, initially set as center (per the setup() call)
  static int oldangle = 90;
  // apparently 15 to 165 deg is a safe range
  int newangle = random(15,165);
  Serial.println(newangle);
  move(oldangle,newangle);
  oldangle = newangle;
}

It starts by placing the arm in the center (in the setup() function) and then should generate a random number (the new angle to go to), in a loop.

What I get is the initial position, then two moves (counterclockwise, then clockwise). The output on the serial console shows 22 and 64, which is consistent with the two moves.

Then everything stops. There is no error message on the console (I do not expect one to be, but I am not sure if there could be any feedback from the Arduino, being a complete beginner). What can be the reason for this stop, after two successful loops?

Answer 1

Just a small mistake! Not much big of a deal :D

In the move function

void move(int from, int to) { // initiate the move to the new angle servoMain.write(to); // wait for the movement to actually happen over the actual angle to move through delay(1000 * speed * int(from-to)); }

suppose the values passed are 20, 35 then the last line would be 1000*speed*(-15) Which is negative therefore the arduino delay function converts the - signed bit to a very large unsigned number.

All you have to do is to take the magnitude of from - to ie |from - to | by calling the abs() function.

your move function would look like this:

void move(int from, int to) { // initiate the move to the new angle servoMain.write(to); // wait for the movement to actually happen over the actual angle to move through delay(1000 * speed * abs(int(from-to))); }

Just alter your move function or copy mine and you'll have no problem at all!