Lego Servo
I approached this assignment with the idea that we should be able to move the motor like a turtle in the lego programming laguage. I was successful in make the motor go forward and backward but the problem is that since goes in both direction it doesn't have a rewind and the range of movement is very small. I would like to try this with two servo motors which would also allow us to turn right and left.
The code I used is given below
d int servoPin = 7; // Control pin for servo motor
int pulseWidth = 0; // Amount to pulse the servo
long lastPulse = 0; // the time in millisecs of the last pulse
int refreshTime = 20; // the time in millisecs needed in between pulses
int val; // variable used to store data from serial port
int minPulse = 500; // minimum pulse width
int maxPulse = 2250; // maximum pulse width
char input[5];
int currentWidth = minPulse;
boolean changed;
void setup()
{
pinMode(servoPin, OUTPUT); // Set servo pin as an output pin
pulseWidth = (maxPulse - minPulse)/2 + minPulse; // Set the motor position to the minimum
Serial.begin(9600); // connect to the serial port
Serial.println("Servo control program ready");
Serial.begin(9600);
updateServo();
changed= false;
}
void loop()
{
memset(input,0,4);
readSerialString(input);
char dir = getDirection(input);
int length = getLength(input);
length = length/10;
Serial.print("Moving ");
Serial.print(dir);
Serial.print(" by ");
Serial.print(length);
if(dir == 'F')
{
length = 9;
}
if(dir == 'B')
{
length = 1;
}
if (length >= 1 && length <= 9) {
length = length - 1;
pulseWidth = (val * (maxPulse-minPulse) / 8) + minPulse; // convert val to microseconds
Serial.print("Moving servo to position ");
Serial.println(pulseWidth,DEC);
}
Serial.print("Moving servo to position ");
Serial.println(pulseWidth,DEC);
updateServo(); // update servo position
}
char getDirection(char *input)
{
if(input[0] == 'F' && input[1] == 'D')
return 'F';
else if(input[0] == 'B' && input[1] == 'K')
return 'B';
else
return '0';
}
int getLength(char *input)
{
int length = (input[2] - '0') * 10 + (input[3] - '0');
return length;
}
void readSerialString (char *strArray) {
int i = 0;
if(!Serial.available()) {
changed = false;
return;
}
while (Serial.available()) {
strArray[i] = Serial.read();
i++;
changed = true;
}
}
void updateServo() {
// pulse the servo again if rhe refresh time (20 ms) have passed:
Serial.println("PulseWidth = ");
Serial.print(pulseWidth);
if (millis() - lastPulse >= refreshTime) {
digitalWrite(servoPin, HIGH); // Turn the motor on
delayMicroseconds(pulseWidth); // Length of the pulse sets the motor position
digitalWrite(servoPin, LOW); // Turn the motor off
lastPulse = millis(); // save the time of the last pulse
}
}
There was some problem with my assignment and my earlier assignment was lost in the website.
The picture of my servo motor turtle is attached
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