Bluetooth Remote Control

https://bertrandmartel.github.io/bluetooth-remote-control

Bluetooth Low Energy remote control based on DK51 board from Nordic Semiconductor with ST7735 1.8 Oled LCD from Adafruit

Features

• HID Service BLE over GATT for full compatibility with Android TV :

• keyboard control :

  • up / down / left / right
  • escape (back)

• consumer control :

  • AC Search
  • AC Home
  • Play/Pause (Android custom keycode)

• Custom Display Service used to receive a compressed bitmap over GATT :

• compressed bitmap is stored temporarily on device flash & removed afterward

• bitmap format is 128*160 fastlz compressed with block of 4096 octet

• regular characteristic write is used (not long write)

• Android application can be used to test :

• hid keys notification

• command led states on DK51 board

• send a bitmap to be displayed on adafruit OLED module

• works fine on Android / Android TV

• works on Apple TV but some keycode differ (consumer control)

• this project doesn't implement any Audio Service for Voice Search

Mode 1 : Android testing application

Mode 2 : BLE HID Service mode

You can't combined Mode 1 & Mode 2 simultaneously.

Project structure

• /firmware - microcontroller code written for NRF DK51 board
• /android - android application to control device

Hardware setup

• NRF51 DK board
  • nrf51822 chipset based on an ARM Cortex M0 processor (128kB flash memory / 16kB RAM)

• Adafruit 1.8" Color TFT Shield with Joystick

Hardware installation

RST is linked to VDD

Build

Get source code

git clone git@github.com:bertrandmartel/bluetooth-remote-control.git
cd bluetooth-remote-control
git submodule update --init --recursive

Configuration

• armgcc toolchain
• sofdevice s130
• nRF5 SDK 11.0.0

Setup / Installation

• follow SDK/Toolchain Installation steps section of this tutorial

• specify NRF51 SDK directory with :

export NRF51_SDK_DIR=/path/to/sdk

Build & flash firmware

cd firmware
make
make flash_softdevice
make flash

Build Android App

cd android
./gradlew build

External library

Firmware

• NRF 51 SDK 11.0.0 : https://www.nordicsemi.com/eng/Products/Bluetooth-low-energy/nRF5-SDK
• fastlz compression library : https://github.com/ariya/FastLZ
• Integration of Adafruit OLED ST7735 1.8 display on NRF51 DK board : https://github.com/bertrandmartel/adafruit-oled-st7735-dk51

Android application

• Android crop image library : https://github.com/lvillani/android-cropimage
• Simple vertical and horizontal color picker : https://github.com/DASAR/ShiftColorPicker
• fastlz compression library : https://github.com/ariya/FastLZ
• appcompat-v7, design & recyclerview-v7

External links

• USB HID keycode : http://www.freebsddiary.org/APC/usb_hid_usages.php
• Android HID keycode/keyevent mapping : https://source.android.com/devices/input/keyboard-devices.html

License

The MIT License (MIT) Copyright (c) 2016 Bertrand Martel