time switch

/ˈtaɪm swɪtʃ/
noun
  1. A device that automatically turns something on or off at a set time.
    • The sprinkler system uses a time-switch to water the garden every morning.
    • We installed a time-switch on the porch light so it turns on at dusk.
    • The oven has a time-switch that starts cooking at 5 PM.