Arduino “having11” Guy
Published © GPL3+

Autonomous Tank With GPS

Use a Devastator Tank Chassis from DFRobot to create an amazing tank that can navigate autonomously and send GPS data.

IntermediateWork in progress4 hours2,491
Autonomous Tank With GPS

Things used in this project

Hardware components

DFRobot Devastator Tank Robot Platform
×1
DFRobot GPS Module with Enclosure
×1
Teensy 3.5
Teensy 3.5
×1
Ultrasonic Sensor - HC-SR04 (Generic)
Ultrasonic Sensor - HC-SR04 (Generic)
×1
Micro Servo 9g
×1
HC-05 Bluetooth Module
HC-05 Bluetooth Module
×1

Software apps and online services

Arduino IDE
Arduino IDE
App Inventor

Hand tools and fabrication machines

Screwdriver
DeWalt Cordless Drill

Story

Read more

Schematics

Schematic

Code

Teensy Code

C/C++
#include <Adafruit_GPS.h>
#include <Servo.h>

Servo pan;

// what's the name of the hardware serial port?
#define GPSSerial Serial1
#define BT Serial3

// Connect to the GPS on the hardware port
Adafruit_GPS GPS(&GPSSerial);

int8_t pins[7] = {38,37,35,36,16,17,23};
int8_t pingPin = 16;
int8_t echoPin = 17;

#define LAT_OFFSET .2752
#define LON_OFFSET .13715
     
// Set GPSECHO to 'false' to turn off echoing the GPS data to the Serial console
// Set to 'true' if you want to debug and listen to the raw GPS sentences
#define GPSECHO false

bool automatic = false;
const int safe_distance = 18; //How many cm away is safe

uint32_t timer = millis();


void setup()
{
  //while (!Serial);  // uncomment to have the sketch wait until Serial is ready
  
  // connect at 115200 so we can read the GPS fast enough and echo without dropping chars
  // also spit it out
  Serial.begin(115200);
  BT.begin(9600);
  Serial.println("Adafruit GPS library basic test!");
  for(int i=0;i<4;i++){
    pinMode(pins[i],OUTPUT);
  }
  pinMode(pingPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pan.attach(pins[6]);
  pan.write(90);
  // 9600 NMEA is the default baud rate for Adafruit MTK GPS's- some use 4800
  GPS.begin(9600);
  // uncomment this line to turn on RMC (recommended minimum) and GGA (fix data) including altitude
  GPS.sendCommand(PMTK_SET_NMEA_OUTPUT_RMCGGA);
  // uncomment this line to turn on only the "minimum recommended" data
  //GPS.sendCommand(PMTK_SET_NMEA_OUTPUT_RMCONLY);
  // For parsing data, we don't suggest using anything but either RMC only or RMC+GGA since
  // the parser doesn't care about other sentences at this time
  // Set the update rate
  GPS.sendCommand(PMTK_SET_NMEA_UPDATE_1HZ); // 1 Hz update rate
  // For the parsing code to work nicely and have time to sort thru the data, and
  // print it out we don't suggest using anything higher than 1 Hz
     
  // Request updates on antenna status, comment out to keep quiet
  GPS.sendCommand(PGCMD_ANTENNA);

  delay(1000);
  
  // Ask for firmware version
  GPSSerial.println(PMTK_Q_RELEASE);
}

void motors(int m1Val, int m2Val){ //0: stop, 1: forward, 2: reverse
  switch(m1Val){
    case 0:
      analogWrite(pins[0], 0);
      analogWrite(pins[1], 0);
      break;
    case 1:
      analogWrite(pins[0], 150);
      analogWrite(pins[1], 0);
      break;
    case 2:
      analogWrite(pins[0], 0);
      analogWrite(pins[1], 150);
      break;
  }
  switch(m2Val){
    case 0:
      analogWrite(pins[2], 0);
      analogWrite(pins[3], 0);
      break;
    case 1:
      analogWrite(pins[2], 150);
      analogWrite(pins[3], 0);
      break;
    case 2:
      analogWrite(pins[2], 0);
      analogWrite(pins[3], 150);
      break;
  }
}

void loop() // run over and over again
{
  if(automatic){
    motors(1,1);
    delay(10);
    int distance = ping();
    if (distance==0) distance = safe_distance + 2; 
    if(distance < safe_distance){
      Serial.println(distance);
      motors(0,0);
      motors(2,2);
      delay(400);
      motors(0,0);
      pan.write(30);
      delay(500);
      int distance_r = ping();
      pan.write(150);
      delay(500);
      int distance_l = ping();
      pan.write(90);
      if(distance_r > safe_distance|| distance_l>safe_distance){
      if(distance_r < distance_l){
        motors(1,2);
        delay(200);
        motors(0,0);
      }
      else if(distance_l < distance_r){
        motors(2,1);
        delay(200);
        motors(0,0);
      }
      }
      else{
        motors(2,2);
        delay(300);
        motors(0,0);
      }
    }
  }
  if(BT.available()>0){
    int cmd = BT.parseInt();
    Serial.println(cmd);
    switch(cmd){
      case 1: //Forward
        motors(1,1);
        delay(400);
        motors(0,0);
        break;
      case 2: //Reverse
        motors(2,2);
        delay(400);
        motors(0,0);
        break;
      case 3: //Right
        motors(2,1);
        delay(400);
        motors(0,0);
        break;
      case 4: //Left
        motors(1,2);
        delay(400);
        motors(0,0);
        break;
      case 5:
        automatic = false;
        motors(0,0);
        break;
      case 6:
        automatic = true;
    }
  }
  // read data from the GPS in the 'main loop'
  char c = GPS.read();
  // if you want to debug, this is a good time to do it!
  if (GPSECHO)
    if (c) Serial.print(c);
  // if a sentence is received, we can check the checksum, parse it...
  if (GPS.newNMEAreceived()) {
    // a tricky thing here is if we print the NMEA sentence, or data
    // we end up not listening and catching other sentences!
    // so be very wary if using OUTPUT_ALLDATA and trytng to print out data
    //Serial.println(GPS.lastNMEA()); // this also sets the newNMEAreceived() flag to false
    if (!GPS.parse(GPS.lastNMEA())) // this also sets the newNMEAreceived() flag to false
      return; // we can fail to parse a sentence in which case we should just wait for another
  }
  // if millis() or timer wraps around, we'll just reset it
  if (timer > millis()) timer = millis();
     
  // approximately every 2 seconds or so, print out the current stats
  if (millis() - timer > 2000) {
    print_gps();
  }
    
}

void print_gps(){
  timer = millis(); // reset the timer
    Serial.print("\nTime: ");
    Serial.print(GPS.hour, DEC); Serial.print(':');
    Serial.print(GPS.minute, DEC); Serial.print(':');
    Serial.print(GPS.seconds, DEC); Serial.print('.');
    Serial.println(GPS.milliseconds);
    Serial.print("Date: ");
    Serial.print(GPS.day, DEC); Serial.print('/');
    Serial.print(GPS.month, DEC); Serial.print("/20");
    Serial.println(GPS.year, DEC);
    Serial.print("Fix: "); Serial.print((int)GPS.fix);
    Serial.print(" quality: "); Serial.println((int)GPS.fixquality);
    if (GPS.fix) {
      Serial.print("Location: ");
      Serial.print(GPS.latitude/100, 5); Serial.print(GPS.lat);
      Serial.print(", ");
      Serial.print(GPS.longitude/100, 5); Serial.println(GPS.lon);
      Serial.print("Speed (knots): "); Serial.println(GPS.speed);
      Serial.print("Angle: "); Serial.println(GPS.angle);
      Serial.print("Altitude: "); Serial.println(GPS.altitude);
      Serial.print("Satellites: "); Serial.println((int)GPS.satellites);
    }
    /*BT.print("\nTime: ");
    BT.print(GPS.hour, DEC); BT.print(':');
    BT.print(GPS.minute, DEC); BT.print(':');
    BT.print(GPS.seconds, DEC); BT.print('.');
    BT.println(GPS.milliseconds);
    BT.print("Date: ");
    BT.print(GPS.day, DEC); BT.print('/');
    BT.print(GPS.month, DEC); BT.print("/20");
    BT.println(GPS.year, DEC);
    BT.print("Fix: "); BT.print((int)GPS.fix);
    BT.print(" quality: "); BT.println((int)GPS.fixquality);
    if (GPS.fix) {
      BT.print("Location: ");
      BT.print(GPS.latitude/100, 5); BT.print(GPS.lat);
      BT.print(", ");
      BT.print(GPS.longitude/100, 5); BT.println(GPS.lon);
      BT.print("Speed (knots): "); BT.println(GPS.speed);
      BT.print("Angle: "); BT.println(GPS.angle);
      BT.print("Altitude: "); BT.println(GPS.altitude);
      BT.print("Satellites: "); BT.println((int)GPS.satellites);
    }*/
    if(GPS.fix){
      BT.println(String((GPS.latitude/100)+LAT_OFFSET,5)+",-"+String((GPS.longitude/100)+LON_OFFSET,5));
    }
    
}

int ping(){
  long duration, inches, cm;
  digitalWrite(pingPin, LOW);
  delayMicroseconds(2);
  digitalWrite(pingPin, HIGH);
  delayMicroseconds(5);
  digitalWrite(pingPin, LOW);
  pinMode(echoPin, INPUT);
  duration = pulseIn(echoPin, HIGH);
  cm = microsecondsToCentimeters(duration);
  return cm;
}

long microsecondsToCentimeters(long microseconds) {
  // The speed of sound is 340 m/s or 29 microseconds per centimeter.
  // The ping travels out and back, so to find the distance of the
  // object we take half of the distance travelled.
  return microseconds / 29 / 2;
}

Credits

Arduino “having11” Guy

Arduino “having11” Guy

81 projects • 539 followers
18 year-old IoT and embedded systems enthusiast. Also an intern at Hackster.io who loves working on projects and sharing knowledge.

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