UNO CODE

#include <Arduino.h>
#include <ArduinoBLE.h>
#include <Stepper.h>

///////////////////////////////////////////////////////
// ----------------------------------------------------
/// THIS CODE RUNS ON THE Arduino R4 - TANK
// ----------------------------------------------------
///////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////
//  this code sends the ultra sonic distance data to the controller
//  we are the peripheral...
////////////////////////////////////////////////////////////////////

// WE ARE UPDATING THE BUTTON CHARACTERISTIC AND READING THE LED STATE CHARACTERISITC
//    we send button value
//    we recieve LED value

// variables for button:
const int buttonPin = 2;
int oldButtonState = LOW;

BLEService duplexService("1000");                                           // create service
BLEByteCharacteristic buttonCharacteristic("1001", BLERead | BLENotify);    // create button characteristic and allow remote device to get notifications
BLEIntCharacteristic joystick_1_characteristic("1002", BLERead | BLEWrite);        // create joystick_1 characteristic and allow remote device to read and write
BLEIntCharacteristic joystick_2_characteristic("1003", BLERead | BLEWrite);        // create joystick_2 characteristic and allow remote device to read and write

const int stepsPerRevolution = 800;

const int stepMotor1 = 3; //step
const int dirMotor1 = 2; //dir
const int stepMotor2 = 5; //step
const int dirMotor2 = 4; //dir
const int stepMotor3 = 6; //step
const int dirMotor3 = 7; //dir
const int stepMotor4 = 9; //step
const int dirMotor4 = 8; //dir

Stepper motor1(stepsPerRevolution, stepMotor1, dirMotor1);
Stepper motor2(stepsPerRevolution, stepMotor2, dirMotor2);
Stepper motor3(stepsPerRevolution, stepMotor3, dirMotor3);
Stepper motor4(stepsPerRevolution, stepMotor4, dirMotor4);

const int MOTOR_SPEED = 60;

int POS = 0;


void setup()
{

        motor1.setSpeed(0);
        motor2.setSpeed(0);
        motor3.setSpeed(0);
        motor4.setSpeed(0);

        motor1.step(0);
        motor2.step(0);
        motor3.step(0);
        motor4.step(0);

  Serial.begin(9600);
  pinMode(LED_BUILTIN, OUTPUT); // use the LED as an output
  pinMode(buttonPin, INPUT_PULLUP); // use button pin as an input

  BLE.begin();  //init BLE module
  BLE.setLocalName("duplexPeripheral");       // set the local name that the peripheral advertises
  BLE.setAdvertisedService(duplexService);    // set the UUID for the service the peripheral advertises:

  duplexService.addCharacteristic(joystick_1_characteristic);
  duplexService.addCharacteristic(joystick_2_characteristic);
  duplexService.addCharacteristic(buttonCharacteristic);

  BLE.addService(duplexService);    // add the service

  joystick_1_characteristic.writeValue(0);
  joystick_2_characteristic.writeValue(0);
  buttonCharacteristic.writeValue(0);

  BLE.advertise();    // start advertising on BLE network
  Serial.println("Peripheral is running");


}

void loop() {
  BLEDevice central = BLE.central();

  if (central)
  {
    Serial.println("Got central connection!");
    while (central.connected())
    {
      byte buttonValue = digitalRead(buttonPin);

      //check if joystick 1 characteristic has been updated...
      if (joystick_1_characteristic.written())
      {
        POS = joystick_1_characteristic.value();
        // if (joy_1_value >1000)
        // {
        //   buttonCharacteristic.writeValue(20);
        // } else {
        //   buttonCharacteristic.writeValue(50);
        // }
        Serial.print("Position: ");
        Serial.println(POS);
      }

      //check if joystick 2 characteristic has been updated...
      // if (joystick_2_characteristic.written())
      // {
      //   int joy_2_value = joystick_2_characteristic.value();
      //   digitalWrite(LED_BUILTIN, joy_2_value);
      //   Serial.print(" JOY_2 data: ");
      //   Serial.println(joy_2_value);
      // }
      if (POS == 0)
        {
        motor1.setSpeed(0);
        motor2.setSpeed(0);
        motor3.setSpeed(0);
        motor4.setSpeed(0);

        motor1.step(0);
        motor2.step(0);
        motor3.step(0);
        motor4.step(0);
        }
      if(POS == 1);
        {
        motor1.setSpeed(60);
        motor2.setSpeed(60);
        motor3.setSpeed(60);
        motor4.setSpeed(60);

        motor1.step(1);
        motor2.step(1);
        motor3.step(1);
        motor4.step(1);

        }
      if (POS == 2)
        {
        motor1.setSpeed(0);
        motor2.setSpeed(0);
        motor3.setSpeed(0);
        motor4.setSpeed(0);

        motor1.step(0);
        motor2.step(0);
        motor3.step(0);
        motor4.step(0);
        }
      if (POS == 3) //Right
        {
        motor1.setSpeed(40);
        motor2.setSpeed(40);
        motor3.setSpeed(40);
        motor4.setSpeed(40);

        motor1.step(1);
        motor2.step(-1);
        motor3.step(1);
        motor4.step(-1);
        }
      if (POS == 4) //Back right
        {
        motor1.setSpeed(0);
        motor2.setSpeed(0);
        motor3.setSpeed(0);
        motor4.setSpeed(0);

        motor1.step(0);
        motor2.step(0);
        motor3.step(0);
        motor4.step(0);
        }
      if (POS == 5) //Backwards
        {
        motor1.setSpeed(60);
        motor2.setSpeed(60);
        motor3.setSpeed(60);
        motor4.setSpeed(60);

        motor1.step(-1);
        motor2.step(-1);
        motor3.step(-1);
        motor4.step(-1);
        }
      if (POS == 6) //Back left
        {
        motor1.setSpeed(0);
        motor2.setSpeed(0);
        motor3.setSpeed(0);
        motor4.setSpeed(0);

        motor1.step(0);
        motor2.step(0);
        motor3.step(0);
        motor4.step(0);
        }
      if (POS == 7) //Left
        {
        motor1.setSpeed(40);
        motor2.setSpeed(40);
        motor3.setSpeed(40);
        motor4.setSpeed(40);

        motor1.step(-1);
        motor2.step(1);
        motor3.step(-1);
        motor4.step(1);
        }
      if (POS == 8) //forward left
        {
        motor1.setSpeed(0);
        motor2.setSpeed(0);
        motor3.setSpeed(0);
        motor4.setSpeed(0);

        motor1.step(0);
        motor2.step(0);
        motor3.step(0);
        motor4.step(0);
        }


    }

    // when the central disconnects, print it out:
    Serial.print("Disconnected from central: ");
    Serial.println(central.address());
  }
}