In this project, we are going to make an Android App that will connect with Arduino Nano via the HC-05 Bluetooth module. This app will control the LED, and motor, and read the temperature-humidity of the environment. We will use a free MIT App Inventor website for building apps via blocks. We will give all the project files for this project. If you are ready let’s get started. Schematic Firstly we made an example circuit to make bidirectional communication. You can see in the picture below which components we use. The main component is Arduino Nano which controls the system. We connect the red LED to the D2 pin. We use the L293D motor driver to control the DC motor. We added AHT10 to get temperature and humidity from the environment. Finally, we added HC-05 to communicate with the Android App. Circuit Schematic Android App We made an Android App via MIT App Inventor which is easy to make basic apps. This app will get and send data via Bluetooth. Let’s start to explain what we did. App