DIY LED Strip Controller with Motion Sensor

This DIY motion-activated lighting system functions by combining a microwave radar sensor with a compact microcontroller to drive a vibrant LED strip. At the heart of the circuit is the RCWL0516 microwave radar sensor, which acts as the movement detector. Unlike standard passive infrared (PIR) sensors that only detect changes in thermal radiation, a microwave radar module emits high-frequency electromagnetic waves and measures the reflections bouncing back from moving objects. When someone walks into the detection zone, the shift in frequency caused by the movement alters the reflected signal, prompting the sensor to send a trigger voltage to the ATtiny85 microcontroller. The ATtiny85 serves as the tiny yet capable brain of the system, running a compiled program that interprets this digital trigger. Upon receiving the signal, the microcontroller outputs precise data signals to control the 2-meter Neopixel LED array. Because Neopixels contain integrated data-driven drivers, the ATtiny85 can sequence custom lighting animations, color shifts, or smooth fading effects along the length of the strip. Power is delivered to the entire setup via a stable 5V power supply, which must supply enough current to handle both the microcontroller and the high-draw LED array. During construction, an Arduino Uno is utilized as an external MCU programmer to flash the compiled code onto the standalone ATtiny85 IC before it is integrated permanently onto a small general-purpose PCB using flexible wires.