Making Two Arduinos Communicate Wirelessly Using HC-05 Bluetooth Modules

This wireless communication system relies on two separate Arduino Uno setups interacting via Bluetooth. On the transmitting side, a potentiometer and a push button act as user inputs, while an LED provides local status feedback, protected by a 220-ohm resistor. The Arduino reads the analog values from the potentiometer and the digital state of the button, packaging this data to send out. An HC-05 Bluetooth module, configured as a master unit, transmits these signals wirelessly. On the receiving end, a second HC-05 module acts as a slave, receiving the wireless data stream and passing it to the second Arduino Uno. This receiving Arduino processes the commands to control a servo motor's position or movement. Because the HC-05 communicates using serial data over UART pins, voltage levels must be stepped down properly using a resistor divider (made of components like 1k-ohm and 2k-ohm resistors) to protect the module's 3.3V logic-sensitive RX pin from the Arduino Uno's 5V output. Both boards are powered and programmed using USB cables via the Arduino IDE, and developers can monitor the data flow externally using a Serial Terminal or PuTTY.