Now you've got all the tools you need to make the nightlight. 1. Use a sensor to detect when it is dark 2. Light an LED when it is dark 3. Turn off the LED when it is bright This is the basic requirement for making a nightlight.

Often when we build devices we want them to react to the external environment. This means we have to implement some sort of sensor to detect the changes. In this case we'll build a simple light detector. To understand this circuit you will need a little electronics background.