Controlling Arduino Mega + USB Host Shield using Android Phone

Hi Guys,

As it says in the title, I want to try to control an Arduino Mega with an Android phone, to start off with I just want to control an LED with my Android by sending a simple 1. So, basically what I have done so far is that I have managed to connect my Arduino to the Arduino Mega which has a USB Shield and I can send digits/messages to and from the phone terminal App and the PC Arduino Serial Monitor. I have tried to play around with the code but I honestly cant figure it out after many attempts, here's the code for sending messages from the phone to computer and vice versa:

#include <SPP.h>
#include <usbhub.h>
// Satisfy IDE, which only needs to see the include statment in the ino.
#ifdef dobogusinclude
#include <spi4teensy3.h>
#include <SPI.h>
#endif

USB Usb;
//USBHub Hub1(&Usb); // Some dongles have a hub inside

BTD Btd(&Usb); // You have to create the Bluetooth Dongle instance like so
/* You can create the instance of the class in two ways */
SPP SerialBT(&Btd); // This will set the name to the defaults: "Arduino" and the pin to "0000"
//SPP SerialBT(&Btd, "Lauszus's Arduino", "1234"); // You can also set the name and pin like so

bool firstMessage = true;

void setup() {
  Serial.begin(115200);
#if !defined(__MIPSEL__)
  while (!Serial); // Wait for serial port to connect - used on Leonardo, Teensy and other boards with built-in USB CDC serial connection
#endif
  if (Usb.Init() == -1) {
    Serial.print(F("\r\nOSC did not start"));
    while (1); //halt
  }
  Serial.print(F("\r\nSPP Bluetooth Library Started"));
}
void loop() {
  Usb.Task(); // The SPP data is actually not send until this is called, one could call SerialBT.send() directly as well

  if (SerialBT.connected) {
    if (firstMessage) {
      firstMessage = false;
      SerialBT.println(F("Hello from Arduino")); // Send welcome message
    }
    if (Serial.available())
      SerialBT.write(Serial.read());
    if (SerialBT.available())
      Serial.write(SerialBT.read());
  }
  else
    firstMessage = true;
}

Any help at all will be greatly appreciated.

One of the things I tried was:

if(SerialBT.read() == '1');
{
digitalWrite(9, HIGH);
}

but it didn't work :S

  if (SerialBT.connected) {

Is connected really a property? Or, are you supposed to be calling a function?

    if (Serial.available())
      SerialBT.write(Serial.read());
    if (SerialBT.available())
      Serial.write(SerialBT.read());

Reading and discarding the incoming data is going to make it really hard to actually use that data.

Have a look at the examples in serial input basics - they are simple, reliable and non-blocking.

You may be interested in this RemoteXY Thread

...R