challenge-bot.com Git - challenge-bot/blob - build-stages/g_follow/g_follow.ino

   1 /*
   2  This program is free software: you can redistribute it and/or modify
   3     it under the terms of the GNU Affero General Public License as
   4     published by the Free Software Foundation, either version 3 of the
   5     License, or (at your option) any later version.
   6
   7     This program is distributed in the hope that it will be useful,
   8     but WITHOUT ANY WARRANTY; without even the implied warranty of
   9     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10     GNU Affero General Public License for more details.
  11
  12     You should have received a copy of the GNU Affero General Public License
  13     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  14  */
  15
  16 // define which pins are connected to which components
  17 int right_motor_forward_pin = 3;
  18 int right_motor_backward_pin = 4;
  19 int right_motor_speed_pin = 5;
  20
  21 int right_echo_pin = 6;
  22 int right_trigger_pin = 7;
  23
  24 int left_motor_forward_pin = 8;
  25 int left_motor_backward_pin = 9;
  26 int left_motor_speed_pin = 10;
  27
  28 int left_echo_pin = 11;
  29 int left_trigger_pin = 12;
  30
  31 void on(int pin){
  32   digitalWrite(pin, HIGH);}
  33
  34 void off(int pin){
  35   digitalWrite(pin, LOW);}
  36
  37 void set_motor(int speed_pin,
  38                int forward_pin,
  39                int backward_pin,
  40                int speed){
  41   if(speed > 0){
  42     off(backward_pin);
  43     on(forward_pin);}
  44   else if(speed < 0){
  45     off(forward_pin);
  46     on(backward_pin);
  47     speed = -speed;}
  48   else{ // speed is 0
  49     off(forward_pin);
  50     off(backward_pin);}
  51   // since speed has been set positive, no need to check if speed < -255.
  52   if(speed > 255){
  53     speed = 255;}
  54   analogWrite(speed_pin, speed);}
  55
  56 void go(int left_motor_speed, int right_motor_speed){
  57   set_motor(left_motor_speed_pin,
  58             left_motor_forward_pin,
  59             left_motor_backward_pin,
  60             left_motor_speed);
  61   set_motor(right_motor_speed_pin,
  62             right_motor_forward_pin,
  63             right_motor_backward_pin,
  64             right_motor_speed);}
  65
  66 int ping(int trigger, int echo){
  67   int ping_time = 0;
  68   // turn off trigger
  69   off(trigger);
  70   delayMicroseconds(2);
  71   // turn on the trigger and leave it on long enough for the
  72   // sonar sensor to notice
  73   on(trigger);
  74   delayMicroseconds(10);
  75   off(trigger);
  76   ping_time = pulseIn(echo, HIGH);
  77   if(ping_time <= 0){
  78     ping_time = 3000;}
  79   // sonar needs some time to recover before pinging again,
  80   // so make sure it gets enough sleep right here.  50 milliseconds
  81   delay(50);
  82   return ping_time;}
  83
  84 void setup(){
  85   Serial.begin(9600);
  86
  87   pinMode(right_motor_speed_pin, OUTPUT);
  88   pinMode(right_motor_forward_pin, OUTPUT);
  89   pinMode(right_motor_backward_pin, OUTPUT);
  90
  91   pinMode(right_echo_pin, INPUT);
  92   pinMode(right_trigger_pin, OUTPUT);
  93
  94   pinMode(left_motor_speed_pin, OUTPUT);
  95   pinMode(left_motor_forward_pin, OUTPUT);
  96   pinMode(left_motor_backward_pin, OUTPUT);
  97
  98   pinMode(left_echo_pin, INPUT);
  99   pinMode(left_trigger_pin, OUTPUT);
 100
 101   off(left_motor_speed_pin);
 102   off(left_motor_forward_pin);
 103   off(left_motor_backward_pin);
 104   off(left_trigger_pin);
 105
 106   off(right_motor_speed_pin);
 107   off(right_motor_forward_pin);
 108   off(right_motor_backward_pin);
 109   off(right_trigger_pin); }
 110
 111 void loop() {
 112   int left_speed;
 113   int right_speed;
 114
 115   // you'll need to adjust these based on your sonar sensor's behavior
 116   int desired_right_ping_time = 800;
 117   int desired_left_ping_time = 800;
 118
 119   unsigned int actual_left_ping_time = ping(left_trigger_pin, left_echo_pin);
 120   unsigned int actual_right_ping_time = ping(right_trigger_pin, right_echo_pin);
 121
 122   left_speed = actual_left_ping_time - desired_left_ping_time;
 123   right_speed = actual_right_ping_time - desired_right_ping_time;
 124
 125   Serial.print("left: ping = ");
 126   Serial.print(actual_left_ping_time);
 127   Serial.print(" speed = ");
 128   Serial.print(left_speed);
 129   Serial.print(" right: ping = ");
 130   Serial.print(actual_right_ping_time);
 131   Serial.print(" speed = ");
 132   Serial.print(right_speed);
 133   Serial.println();
 134
 135   go(left_speed, right_speed); }