DC Phone Train Control

To control DC trains using your phone, you will need two boards. They are:

esp32 DEVKIT

L298n

And the app at this link called Arduino Train DEMO

And you will need a sketch. The sketch comes from entry level.

A copy of the sketch is at the bottom of this page.

Programming the boards requires a bit of attention. It is best to watch how it is done.

Here is a good video. Not that it opens with a screen that says, “Finally after days of working I did control my ho scale train on my phone. ”

I have broken it down into specific images and put them in a gallery below. I will update the images with my own as I build this system myself using his video as a guide.

You need the following boards

esp32 DEVKIT

L298n

This gallery shows the step by step process.

//-------------------------------------------------------------------//
//   WWW.ARDUINORAILWAYCONTROL.COM                                   //
//-------------------------------------------------------------------//
//   QUICK START                                                     //
//   ESP32                                                           //
//   ANDROID TRAIN APPS                                              //
//   https://play.google.com/store/apps/dev?id=8362636330024617247   //
//   PROTOCOL 2.4                                                    //   
//   V.1.2020  Steve Massikker                                       //
//-------------------------------------------------------------------//

#include "BluetoothSerial.h"

#define LED_BUILTIN 2
#define L298_ENA 13
#define L298_IN1 12
#define L298_IN2 14

#if !defined(CONFIG_BT_ENABLED) || !defined(CONFIG_BLUEDROID_ENABLED)
#error Bluetooth is not enabled! Please run `make menuconfig` to and enable it
#endif

BluetoothSerial SerialBT;

// VARIABLES //
bool stringComplete = false;
String inputString = ""; 

// 24 speed
byte speedArray [] = {20,30,40,50,60,70,80,90,100,110,120,130,140,150,160,170,180,190,200,210,220,230,240,255};
byte speedTrain = 0;


// Setting PWM properties
const int freq = 100;
const int pwmChannel_A = 0;
const int resolution = 8;
int dutyCycle = 0;


void setup() {
  SerialBT.begin("ArduinoTrain"); //Bluetooth device name
  SerialBT.register_callback(callback); // Check connection
  inputString.reserve(4);

  // Configure GPIO
  ledcSetup(pwmChannel_A, freq, resolution);

  // Attach GPIO
  ledcAttachPin(L298_ENA, pwmChannel_A);
  pinMode(L298_IN1, OUTPUT);
  pinMode(L298_IN2, OUTPUT);
  pinMode(LED_BUILTIN, OUTPUT);

  // Set default direction to FORWARD
  digitalWrite(L298_IN1, HIGH);
  digitalWrite(L298_IN2, LOW);
}


void loop() {

// ---- START PARSING INCOMING APP COMMANDS
  if (stringComplete) {

    if (inputString.charAt(0) =='a') {
      // Speed 
      if (inputString.charAt(1) =='0') {
        if (inputString.charAt(2) =='0') speedTrain = 0;
        if (inputString.charAt(2) =='1') speedTrain = speedArray[0];
        if (inputString.charAt(2) =='2') speedTrain = speedArray[1];
        if (inputString.charAt(2) =='3') speedTrain = speedArray[2];
        if (inputString.charAt(2) =='4') speedTrain = speedArray[3];
        if (inputString.charAt(2) =='5') speedTrain = speedArray[4];
        if (inputString.charAt(2) =='6') speedTrain = speedArray[5];
        if (inputString.charAt(2) =='7') speedTrain = speedArray[6];
        if (inputString.charAt(2) =='8') speedTrain = speedArray[7]; 
        if (inputString.charAt(2) =='9') speedTrain = speedArray[8];
      } 
      if (inputString.charAt(1) =='1') {
        if (inputString.charAt(2) =='0') speedTrain = speedArray[9];
        if (inputString.charAt(2) =='1') speedTrain = speedArray[10];
        if (inputString.charAt(2) =='2') speedTrain = speedArray[11];
        if (inputString.charAt(2) =='3') speedTrain = speedArray[12];
        if (inputString.charAt(2) =='4') speedTrain = speedArray[13];
        if (inputString.charAt(2) =='5') speedTrain = speedArray[14];
        if (inputString.charAt(2) =='6') speedTrain = speedArray[15];
        if (inputString.charAt(2) =='7') speedTrain = speedArray[16]; 
        if (inputString.charAt(2) =='8') speedTrain = speedArray[17];
        if (inputString.charAt(2) =='9') speedTrain = speedArray[18];   
      }
      if (inputString.charAt(1) =='2') {
        if (inputString.charAt(2) =='0') speedTrain = speedArray[19];
        if (inputString.charAt(2) =='1') speedTrain = speedArray[20];
        if (inputString.charAt(2) =='2') speedTrain = speedArray[21];
        if (inputString.charAt(2) =='3') speedTrain = speedArray[22]; 
        if (inputString.charAt(2) =='4') speedTrain = speedArray[23];         
      }

      // Direction and Stop
      if (inputString.charAt(1) =='d') {
        if (inputString.charAt(2) =='f') { // (f) Forward
          digitalWrite(L298_IN1, HIGH);
          digitalWrite(L298_IN2, LOW); 
        }
        if (inputString.charAt(2) =='b') { // (b) Backward
          digitalWrite(L298_IN1, LOW);
          digitalWrite(L298_IN2, HIGH); 
        }
        if (inputString.charAt(2) =='s') { // (s) Stop button
          speedTrain = 0;
        } 
      }

      ledcWrite(pwmChannel_A, speedTrain); 
    }

    inputString = "";
    stringComplete = false;
  }
  
  bluetoothEvent();
}


//// FUNCTIONS ////

void bluetoothEvent() {
  if (SerialBT.available()) {
    char inChar = (char)SerialBT.read();
    inputString += inChar;
    if (inChar == 'z') {
      stringComplete = true;
    }
  }
}

void callback(esp_spp_cb_event_t event, esp_spp_cb_param_t *param){
  if(event == ESP_SPP_SRV_OPEN_EVT) digitalWrite(LED_BUILTIN, HIGH);
  if(event == ESP_SPP_CLOSE_EVT ) {
    digitalWrite(LED_BUILTIN, LOW);
    digitalWrite(L298_IN1, HIGH);
    digitalWrite(L298_IN2, LOW);
    ledcWrite(pwmChannel_A, 0); 
  }
}