Android/Kotlin – Android TV Remote Control: A Comprehensive Guide to Building Your Own

Are you tired of losing your TV remote control or having to get up from the couch to adjust the volume? Well, put those days behind you with the power of Android/Kotlin development! In this article, we’ll take you through a step-by-step guide on how to build your own Android TV remote control using Kotlin programming language.

What You’ll Need

Before we dive into the development process, make sure you have the following prerequisites:

• Android Studio installed on your computer (version 4.1 or later)
• Kotlin programming language installed and configured in Android Studio
• A physical Android device or emulator (for testing purposes)
• An Android TV device or emulator

Understanding the Android TV Remote Control Architecture

Before we start building our own remote control, it’s essential to understand how the Android TV remote control architecture works.

IR Blaster vs. HDMI-CEC

Android TV devices use either Infrared (IR) blasters or HDMI-CEC (Consumer Electronics Control) to communicate with other devices. IR blasters send infrared signals to control devices, while HDMI-CEC uses the HDMI connection to control devices. For this project, we’ll focus on using IR blasters.

Android TV Remote Control Protocol

The Android TV remote control protocol is built on top of the Android Things API. It uses a combination of IR signals and Android Things services to communicate with the TV. We’ll use the Android Things SDK to develop our remote control app.

Setting Up the Android TV Remote Control Project

Now that we have a basic understanding of the architecture, let’s set up our project in Android Studio:

<!-- Create a new project in Android Studio -->
<!-- Choose "Empty Activity" and name your project, e.g., "AndroidTVRemoteControl" -->
<!-- Set the minimum SDK to API 21 (Android 5.0) or higher -->

Adding the Android Things SDK

In the `build.gradle` file, add the following dependencies:

dependencies {
    implementation 'com.google.android.things:androidthings:1.0'
    implementation 'com.google.android.things:android-things-sdk:1.0'
}

Creating the User Interface

Create a new layout file `activity_main.xml` and add the following code:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <Button
        android:id="@+id/btn_power"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Power" />

    <Button
        android:id="@+id/btn_volume_up"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Volume Up" />

    <Button
        android:id="@+id/btn_volume_down"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Volume Down" />

    <Button
        android:id="@+id/btn_channel_up"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Channel Up" />

    <Button
        android:id="@+id/btn_channel_down"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Channel Down" />

</LinearLayout>

Implementing the Android TV Remote Control Logic

In the `MainActivity.kt` file, add the following code:

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import android.view.View
import android.widget.Button
import com.google.android.things.pio.PeripheralManager

class MainActivity : AppCompatActivity() {

    private lateinit var peripheralManager: PeripheralManager
    private lateinit var irSender: IrSender

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        peripheralManager = PeripheralManager.getInstance()
        irSender = IrSender(peripheralManager)

        val btnPower = findViewById<Button>(R.id.btn_power)
        val btnVolumeUp = findViewById<Button>(R.id.btn_volume_up)
        val btnVolumeDown = findViewById<Button>(R.id.btn_volume_down)
        val btnChannelUp = findViewById<Button>(R.id.btn_channel_up)
        val btnChannelDown = findViewById<Button>(R.id.btn_channel_down)

        btnPower.setOnClickListener { sendIrCommand(irSender, "power") }
        btnVolumeUp.setOnClickListener { sendIrCommand(irSender, "volume_up") }
        btnVolumeDown.setOnClickListener { sendIrCommand(irSender, "volume_down") }
        btnChannelUp.setOnClickListener { sendIrCommand(irSender, "channel_up") }
        btnChannelDown.setOnClickListener { sendIrCommand(irSender, "channel_down") }
    }

    private fun sendIrCommand(irSender: IrSender, command: String) {
        // Send IR command to TV
        irSender.sendIrCommand(command)
    }
}

Defining the IR Commands

Create a new file `IrCommands.kt` and add the following code:

object IrCommands {
    val POWER = byteArrayOf(0x16, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00)
    val VOLUME_UP = byteArrayOf(0x16, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00)
    val VOLUME_DOWN = byteArrayOf(0x16, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00)
    val CHANNEL_UP = byteArrayOf(0x16, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00)
    val CHANNEL_DOWN = byteArrayOf(0x16, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00)
}

Defining the IrSender Class

Create a new file `IrSender.kt` and add the following code:

import com.google.android.things.pio.IrTx

class IrSender(private val peripheralManager: PeripheralManager) {
    private lateinit var irTx: IrTx

    init {
        irTx = peripheralManager.openIrTx("IR_TX")
    }

    fun sendIrCommand(command: String) {
        when (command) {
            "power" -> irTx.transmit(IrCommands.POWER)
            "volume_up" -> irTx.transmit(IrCommands.VOLUME_UP)
            "volume_down" -> irTx.transmit(IrCommands.VOLUME_DOWN)
            "channel_up" -> irTx.transmit(IrCommands.CHANNEL_UP)
            "channel_down" -> irTx.transmit(IrCommands.CHANNEL_DOWN)
            else -> Log.e("IrSender", "Invalid command: $command")
        }
    }
}

Testing the Android TV Remote Control

Now that we’ve implemented the logic, it’s time to test our Android TV remote control:

1. Connect your Android device to your computer using a USB cable.
2. In Android Studio, select “Run” > “Run ‘app'” to build and deploy the app to your connected device.
3. On your Android device, open the app and press the buttons to test the IR commands.
4. Point the IR blaster of your Android device at your TV and test the commands.

Button	Action
Power	Toggles the TV power on/off
Volume Up	Increases the TV volume
Volume Down	Decreases the TV volume
Channel Up	Changes the TV channel up
Channel Down	Changes the TV channel down

Frequently Asked Question

Get to know more about Android/Kotlin – Android TV Remote Control with these frequently asked questions!