Tutorial : How to use : USB OTG Bridge Serial UART for APP Inventor 2 and ARDUBLOCK 

play.google.co...
Demo: play.google.co...
Students, teachers, passionate communication discover the first application to control devices FTDI UART with USB connector (Arduino Uno, Mega, Yun, FTDI XBee ...) directly from the development tool APP INVENTOR 2 . (No need for extra Host Shield or Bluetooth. All you need is a Micro USB OTG to USB Adapter.)
USB Bridge for App Inventor 2 allows through a USB OTG cable to achieve a seamless interface between a USB device and the development tool APP INVENTOR 2.
You'll be able to develop your own new applications using the power of app inventor 2 (graphic, sensors, databases ...) and the powers of your devices available (LED RGB, Servo, AX12A, DC Motor...) equipped with a USB UART at 115200 bauds
Recycle your old phones and android tablets to achieve beautiful HIM for your microcontroller-based applications.
If your device is not recognized, please send me the references Vendor ID and Product ID as the following example to the arduino uno: Vendor ID: 0x2341, Product ID: 0x0001
USB Host mode support on android device and Android 3.1+ are required
Example:Control an arduino uno card with otg usb and APP INVENTOR 2
Send and receive datas from Arduino with Serial.println(), Serial.print() , Serial.read() in 115200 baud rate.
github.com/S2I...