Hello,
I'm working on a project for my Design class using Arduino and a Ping ultrasound sensor to avoid objects.
Check it out at http://letsmakerobots.com/node/25837
I've figured out the hardware issues are because I need a motor driver that can handle more current. The L293D cant handle the current the motors require.
The problem I'm stuck at now is with the code. I'm new to Arduino and can use some help with writing it. The code I have here works but as you can see in the video in my post, the vehicle is very fast, probably too fast to work correctly. Using PWM on the enable pins or directly on the motor pins will allow me to control the speed. I tried editing it code in every way I can think yet still no success.
I would also like to add a section to the code to allow the servo to pan while its driving so it will avoid it from running into anything at any angle OR when it comes to an object look left and right and choose the best direction. If anyone can help would be greatly appreciated.
Heres the code:
#include <Ping.h>
const int numOfReadings = 10; // number of readings to take/ items in the array
int readings[numOfReadings]; // stores the distance readings in an array
int arrayIndex = 0; // arrayIndex of the current item in the array
int total = 0; // stores the cumlative total
int averageDistance = 0; // stores the average value
const int pingpin = 12; // ping pin (digital 12)
unsigned long pulseTime = 0; // stores the pulse in Micro Seconds
unsigned long distance = 0; // variable for storing the distance (cm)
int motor1Pin1 = 3; // pin 2 on L293D
int motor1Pin2 = 4; // pin 7 on L293D
int enable1Pin = 9; // pin 1 on L293D
int motor2Pin1 = 5; // pin 10 on L293D
int motor2Pin2 = 6; // pin 15 on L293D
int enable2Pin = 10; // pin 9 on L293D
void setup() {
// set the motor pins as outputs:
Serial.begin(9600);
pinMode(motor1Pin1, OUTPUT);
pinMode(motor1Pin2, OUTPUT);
pinMode(enable1Pin, OUTPUT);
pinMode(motor2Pin1, OUTPUT);
pinMode(motor2Pin2, OUTPUT);
pinMode(enable2Pin, OUTPUT);
// set enablePins high so that motor can turn on:
digitalWrite(enable1Pin, HIGH);
digitalWrite(enable2Pin, HIGH);
pinMode(pingpin, OUTPUT);
pinMode(pingpin, INPUT);
// create array loop to iterate over every item in the array
for (int thisReading = 0; thisReading < numOfReadings; thisReading++) {
readings[thisReading] = 0;
}
}
void loop() {
pinMode(pingpin, OUTPUT);
digitalWrite(pingpin, HIGH); // send 10 microsecond pulse
delayMicroseconds(10); // wait 10 microseconds before turning off
digitalWrite(pingpin, LOW); // stop sending the pulse
pinMode(pingpin, INPUT);
pulseTime = pulseIn(pingpin, HIGH); // Look for a return pulse, it should be high as the pulse goes low-high-low
distance = pulseTime/58; // Distance = pulse time / 58 to convert to cm.
total= total - readings[arrayIndex]; // subtract the last distance
readings[arrayIndex] = distance; // add distance reading to array
total= total + readings[arrayIndex]; // add the reading to the total
arrayIndex = arrayIndex + 1; // go to the next item in the array
// At the end of the array (10 items) then start again
if (arrayIndex >= numOfReadings) {
arrayIndex = 0;
}
averageDistance = total / numOfReadings; // calculate the average distance
delay(10);
// check the average distance and move accordingly
if (averageDistance <= 10){
// go backwards
digitalWrite(motor1Pin1, HIGH);
digitalWrite(motor1Pin2, LOW);
digitalWrite(motor2Pin1, HIGH);
digitalWrite(motor2Pin2, LOW);
}
if (averageDistance <= 25 && averageDistance > 10) {
// turn
digitalWrite(motor1Pin1, HIGH);
digitalWrite(motor1Pin2, LOW);
digitalWrite(motor2Pin1, LOW);
digitalWrite(motor2Pin2, HIGH);
}
if (averageDistance > 25) {
// go forward
digitalWrite(motor1Pin1, LOW);
digitalWrite(motor1Pin2, HIGH);
digitalWrite(motor2Pin1, LOW);
digitalWrite(motor2Pin2, HIGH);
}
}
