Bluetooth Operated LED Desk Lamp

The Bluetooth Operated LED Desk Lamp system integrates wireless communication, microcontroller processing, and power transistor switching to control a 12V DC white LED module. At the core of the circuit is the Arduino Uno microcontroller board, which interfaces with an HC-05 compatible Bluetooth module via serial communication. When a user interacts with the RemoteXY Android App on a smartphone, control commands are transmitted wirelessly over Bluetooth to the HC-05 module and routed into the Arduino Uno. The microcontroller processes these incoming signals and generates pulse-width modulation (PWM) output signals. Because the Arduino's digital output pins cannot directly supply the higher current required by a 12V LED module, the control signal is fed through a 1k ohm resistor into the base of an S8050 high-current transistor. This transistor operates as a solid-state electronic switch, modulating the current flowing from the external power supply through the 12V LED load. Additionally, a 1N4007 silicon diode is incorporated into the circuit configuration to protect sensitive components from inductive voltage spikes or reverse polarity issues. By varying the duty cycle of the PWM signal through the mobile application, the user can seamlessly adjust the brightness of the desk lamp or toggle it entirely on and off from a distance.