Solartech Infra-red Sensor operates using a 'moving heat sensor' which will switch on a light or a hooter or both whenever a warm object (such as a human, large animal, car or motor cycle) enters its sensing field. It can be set to switch on for a period of between 5 seconds and 20 minutes. During the period from dusk to dawn if a person approaches this unit will instantly activate its courtesy lights. Once activated, the lights will remain on while a person is present, automatically switching off after their departure.