Automatic Night Lamp with Morning Alarm

This circuit project automatically activates a night lamp when the bedroom light is turned off. The lamp stays illuminated until the light sensor detects daylight.

The circuit operates using a light-dependent resistor (LDR) as the primary sensor to detect ambient light levels. When the bedroom light is switched off, the LDR's resistance increases due to the lack of light, which triggers a transistor-based switching mechanism. The transistor acts as a switch that allows current to flow to the night lamp, turning it on.

The circuit can be designed with a simple configuration. The LDR is connected in a voltage divider arrangement with a fixed resistor. The output from this voltage divider is fed into the base of a bipolar junction transistor (BJT). When the light level drops below a certain threshold, the voltage at the transistor's base becomes sufficient to turn it on, allowing current to flow from the collector to the emitter, thus powering the night lamp.

Additionally, a small capacitor can be included in parallel with the lamp to provide a delay in turning off the lamp when daylight is detected, ensuring that the lamp does not flicker during brief changes in light conditions. A potentiometer can also be added to adjust the sensitivity of the LDR, allowing users to customize the light level at which the night lamp activates.

This circuit is particularly useful for enhancing safety and convenience in a bedroom setting, as it provides automatic illumination during the night without the need for manual operation. The design can be powered using a standard AC to DC adapter, ensuring compatibility with common night lamps. Proper insulation and safety measures should be implemented to prevent electrical hazards.This circuit project automatically turns on a night lamp when bedroom light is switched off. The lamp remains ON until the light sensor senses daylight in.. 🔗 External reference