LEZIONE n° 5 – MOTORI
La lezione è sui motori e sulla loro gestione. Si useranno i motori, ma vedremo che abbiamo bisogno di una schield di controllo degli stessi (in pratica stiamo usando l’equivalente di un “ponte H”, il vecchio integrato 298). Per far funzionare i motori sarà necessaria una potenza superiore a quella che possiamo prelevare dalla porta USB del PC. Dovremo necessariamente utilizzare un generatore esterno.
Per provare a fare le modifiche proposte copiare il listato (colorato in rosso) ed incollarlo in un editor di solo testo [Notepad ad esempio]
listato programma esempio numero 8:
/*
contollo motori
*/
//const int ledPin = 13; // the number of the LED pin
int pwm_a = 3; //PWM control for motor outputs 1 and 2 is on digital pin 10
int pwm_b = 11; //PWM control for motor outputs 3 and 4 is on digital pin 11
int dir_b = 13; //direction control for motor outputs 3 and 4 is on digital pin 13
// TAVOLA UNO
int dir_a = 12; //direction control for motor outputs 1 and 2 is on digital pin 12
int speed_outA = 100; //speed
int speed_outB = 100; //speed
int speedL = 50; //speed sotto i 40 non riescono a girare
int speedH = 100; //speed
void setup()
{
Serial.begin(9600);
pinMode(pwm_a, OUTPUT); //Set control pins to be outputs
pinMode(pwm_b, OUTPUT);
pinMode(dir_a, OUTPUT);
pinMode(dir_b, OUTPUT);
analogWrite(pwm_a, speedL); //set both motors to run at (100/255 = 39)% duty cycle (slow)
analogWrite(pwm_b, speedL);
}
void loop()
{
int tempo = 3000;
Serial.print(” AVANTI \n ” );
delay(10);
digitalWrite(dir_a, HIGH); //Set motor direction, 1 low, 2 high
digitalWrite(dir_b, LOW); //Set motor direction, 3 high, 4 low
speed_outA = speedL;
speed_outB = speedL;
analogWrite(pwm_a, speed_outA); //set both motors to run at 100% duty cycle (fast)
analogWrite(pwm_b, speed_outB);
Serial.print(“velocita motore A = ” );
Serial.print(speed_outA);
delay(10);
Serial.print(” velocita motore B = ” );
Serial.print(speed_outB);
Serial.print(“\n “);
delay(10);
// digitalWrite(ledPin, HIGH);
delay(tempo);
speed_outA = speedH;
speed_outB = speedH;
analogWrite(pwm_a, speed_outA); //set both motors to run at 100% duty cycle (fast)
analogWrite(pwm_b, speed_outB);
Serial.print(“velocita motore A = ” );
Serial.print(speed_outA);
delay(10);
Serial.print(” velocita motore B = ” );
Serial.print(speed_outB);
Serial.print(“\n “);
delay(10);
// digitalWrite(ledPin, LOW);
delay(tempo);
Serial.print(” INDIETRO \n ” );
delay(10);
digitalWrite(dir_a, LOW); //Set motor direction, 1 low, 2 high
digitalWrite(dir_b, HIGH); //Set motor direction, 3 high, 4 low
speed_outA = speedL;
speed_outB = speedL;
analogWrite(pwm_a, speed_outA); //set both motors to run at 100% duty cycle (fast)
analogWrite(pwm_b, speed_outB);
Serial.print(“velocita motore A = ” );
Serial.print(speed_outA);
delay(10);
Serial.print(” velocita motore B = ” );
Serial.print(speed_outB);
Serial.print(“\n “);
delay(10);
// digitalWrite(ledPin, HIGH);
delay(tempo);
speed_outA = speedH;
speed_outB = speedH;
analogWrite(pwm_a, speed_outA); //set both motors to run at 100% duty cycle (fast)
analogWrite(pwm_b, speed_outB);
Serial.print(“velocita motore A = ” );
Serial.print(speed_outA);
delay(10);
Serial.print(” velocita motore B = ” );
Serial.print(speed_outB);
Serial.print(“\n “);
delay(10);
// digitalWrite(ledPin, LOW);
delay(tempo);
}
listato programma esempio numero 9:
/*
controllo di una coppia di motori secondo il valore letto da due potenziometri
*/
int sensorPin = A0;
int sensorValue = 0; // variable to store the value coming from the sensor
int pwm_a = 3; //PWM control for motor outputs 1 and 2 is on digital pin 10
int pwm_b = 11; //PWM control for motor outputs 3 and 4 is on digital pin 11
int dir_a = 12; //direction control for motor outputs 1 and 2 is on digital pin 12
int dir_b = 13; //direction control for motor outputs 3 and 4 is on digital pin 13
int speed_outA = 100; //speed
int speed_outB = 100; //speed
int speedL = 50; //speed sotto i 40 non riescono a girare
int speedH = 100; //speed
int versusH = HIGH; //speed
int versusL = LOW; //speed
int versusA = 0; //speed
int versusB = 0; //speed
int soglia = 500; //soglia
int TEMPO = 2000; //soglia
void setup()
{
Serial.begin(9600);
pinMode(pwm_a, OUTPUT); //Set control pins to be outputs
pinMode(pwm_b, OUTPUT);
pinMode(dir_a, OUTPUT);
pinMode(dir_b, OUTPUT);
analogWrite(pwm_a, speedL); //set both motors to run at (100/255 = 39)% duty cycle (slow)
analogWrite(pwm_b, speedL);
}
void loop()
{
// read the state of the pushbutton value:
sensorValue = analogRead(sensorPin);
// print the results to the serial monitor:
Serial.print(“\n “);
Serial.print(“sensor = ” );
Serial.print(sensorValue);
Serial.print(“\n\n “);
delay(10);
if (sensorValue <= soglia){
versusA = versusH;
versusB = versusL;
Serial.print(” AVANTI \n ” );
delay(10);
}
else {
versusA = versusL;
versusB = versusH;
Serial.print(” INDIETRO \n ” );
delay(10);
}
digitalWrite(dir_a, versusA); //Set motor direction, 1 low, 2 high
digitalWrite(dir_b, versusB); //Set motor direction, 3 high, 4 low
speed_outA = speedL;
speed_outB = speedL;
analogWrite(pwm_a, speed_outA); //set both motors to run at 100% duty cycle (fast)
analogWrite(pwm_b, speed_outB);
Serial.print(“velocita motore A = ” );
Serial.print(speed_outA);
delay(10);
Serial.print(” velocita motore B = ” );
Serial.print(speed_outB);
Serial.print(“\n “);
delay(10);
// digitalWrite(ledPin, HIGH);
delay(TEMPO);
speed_outA = speedH;
speed_outB = speedH;
analogWrite(pwm_a, speed_outA); //set both motors to run at 100% duty cycle (fast)
analogWrite(pwm_b, speed_outB);
Serial.print(“velocita motore A = ” );
Serial.print(speed_outA);
delay(10);
Serial.print(” velocita motore B = ” );
Serial.print(speed_outB);
Serial.print(“\n “);
delay(10);
// digitalWrite(ledPin, LOW);
delay(TEMPO);
}
Modifiche proposte:
- Cambiare i tempi
- Cambiare il potenziometro
- Accendere un led (di colore diverso) secondo il verso
di seguito le slide della lezione
(45)
