This is a small app to send a text string to Teensy 3 via bluetooth using a simple Android app
The app was made for free in the MIT App INventor online playground, and used code from other projects including Random Nerd - http://randomnerdtutorials.com/android-app-that-sends-a-message-to-your-arduino/
The app is used to connect the Android phone to the Teensy 3 via a cheap bluetooth module HC-07. A text string can be sent to the Teensy from the Android phone, and this is then sent to the Arduino IDE Serial Terminal window as a check. This is just a simple first step in connecting for anyone who want to explore this type of connectivity