A Photocell, also known as a dusk to dawn, acts as a light sensor. This automatically turns 12v garden lights on at dusk, which then remain on throughout the night until they turn off again at dawn. This adds safety to the home, lighting up areas such as stairways to and from entrances, and also acts as a deterrent to intruders. When using LED lights, they are surprisingly cheap to run throughout the night, costing as little a £2 per year!

A PIR, also known as a passive infra red motion sensor, is only triggered when movement is detected, as the name suggests. Adjustable settings allow the user to easily control how long the light remains illuminated until it turns off, as well as how sensitive the sensor it to movement and whether the sensor is to work in daytime as well as during darkness.