Controlling the steering servo with a mouse: the Arduino code

On the Arduino side, I also adapted the sketch to fits with my purpose:

#include <Servo.h>

Servo xservo; // xservo is the direction servo

int xpos= 0;

void setup(){

xservo.attach(9); //attach the servo to pin 9

Serial.begin(9600); // 9600 is the rate of communication

}

void loop() {

static int v = 0; // value to be sent to the servo (0-180)

if ( Serial.available()) {

char ch = Serial.read(); // read in a character from the serial port and assign to ch

switch(ch) { // switch based on the value of ch, it will be only x in this case

case '0'...'9': // if it's numeric

v = v * 10 + ch - '0';

/*

so if the chars sent are 45x (turn x servo to 45 degs)..

v is the value we want to send to the servo and it is currently 0

The first char (ch) is 4 so

0*10 = 0 + 4 - 0 = 4;

Second char is 4;

4*10 = 40 + 5 = 45 - 0 = 45;

Third char is not a number(0-9) so we drop through...

*/

break;

case 'x': // if it's x

/*

....and land here

where we send the value of v which is now 45 to the x servo

and then reset v to 0

*/

v = constrain(v, 60, 130); // constrain the value to be between 60 and 130

xservo.write(v); // send the value to the servo

delay(25);

v = 0; // reset this value to 0

break;

}

}

}