Night Light Circuit

Waking up in the middle of the night because you need a drink of water or need to go to the bathroom can be annoying. Especially when it’s pitch black and you can’t see anything. Nonetheless, you daringly walk forward and end up bumping into a wall or worse stub your toe. A solution to both of these problems is a night light.

My circuit contains a 10,000 Ω resistor that is wired in series with a photoresistor, which is both wired in parallel with an NPN transistor, a 330 Ω resistor and a red LED to generate light.

The night light functions by using an LDR, an LDR or a light-dependent resistor is a variable resistor that increases in resistance the brighter it is. So when it’s morning or the lights are on, the LED will switch off conserving energy. The base of the transistor is wired with the first parallel circuit so it acts as a switch and the second resistor reduces the voltage so as to not fuse the LED.

My night light has a very simple design with few points of failure, which is good for something like a light that has to be reliable. My next steps to further develop the night light would be to make an enclosure for it, so the live wires are covered and the circuit is protected. In addition, I would add more LEDs to make the light brighter and more visible. Finally, I would utilize an internal battery in order for the night light to be wireless, the only requirement would be to replace the battery every so often.