Add ArduinoBluetoothHardware and example

[sktometometo]

Add ArduinoBluetoothHardware.h and example for ESP32 Bluetooth Serial.

This PR enables rosserial connection over bluetooth of ESP32. I don't know who originaly develop this usage, but already some uses this.

• https://techtutorialsx.com/2018/03/09/esp32-arduino-serial-communication-over-bluetoth-hello-world/

I thinks this will be useful for otherESP32 rosserial users.

I confirmed that example program works with boards below

• ESP32-DevKitC-32E
• M5Stack Core
• M5Stack Core2
• M5StickC

Usage

FIrst, burn the example sketch to your ESP32 board. After that, connect your PC's bluetooth interface to esp32 board

bluetoothctl
scan on # check MAC address of your device
scan off
pair <MAC address of your device>
trust <MAC address of your device>
connect <MAC address of your device>
info <MAC address of your device> # check if your device is successfully connected

And bind bluetooth serial connection to /dev/rfcomm1

sudo rfcomm bind 1 <MAC address of your device>
sudo stty -F /dev/rfcomm1 57600 cs8

Now you can use rosserial over bluetooth

roscore

rosrun rosserial_python serial_node.py _port:=/dev/rfcomm1 _baud:=57600

[smiiisato]

I'm using devkit-v1 from esp32 and it didn't connect at all. But https://blog.51cto.com/u_12369060/5192168とhttps://askubuntu.com/questions/137794/why-is-my-bluetooth-connection-always-failing I did sudo apt install blueman and used blueman-manager to set up serial communication and it worked fine. Thank you very much.

[k-okada]

tips: to use this with latest noetic branch, we may need https://github.com/ros-drivers/rosserial/pull/448.