DIY: Make Your Own Nifty Night Lamp

The DIY Nifty Night Lamp is an automated, transformer-less analog circuit that powers a blue LED in darkness using an LDR (Light Dependent Resistor) sensor. The circuit connects directly to a 230V AC mains supply via input connector CON1. Safety and voltage reduction are primarily handled by a high-voltage 0.47uF, 400V capacitor (C2) working alongside a 1N4007 rectifier diode (D1) to step down and convert the AC power into a usable DC level. Resistors R1 and R2 (47-ohm) and R3 (470-kilo-ohm) set up the necessary biasing and current-limiting parameters for the system. The core intelligence relies on an ambient light-sensing voltage divider formed by the GL5528 LDR and its associated resistors. When the room light drops, the resistance of the LDR increases, shifting the voltage level at the base of the SS9014 transistor (T1). This transistor acts as an electronic switch; as ambient light fades, T1 turns on, allowing current to flow through and illuminate the blue LED (LED1). When ambient light returns, the LDR resistance drops, turning off the transistor and extinguishing the LED. Because the entire assembly is built on a custom PCB or perf board, it can be housed neatly in a waterproof and flame-retardant enclosure.