Pictured below is a hen house door controller which will automatically open the hen house door in the morning and close it again at night to protect the birds from foxes and other predators.
This version instead takes an input from a light detector (click here for our article introducing Light Dependent Resistors), and uses this to detect dawn and dusk.
When dusk begins, the motor turns one way to lower the door until it presses against and closes the lower roller switch which acts as a limit switch. Similarly, when dawn begins the following morning, the motor turns the other way to raise the door until it closes the upper roller switch.
(For the explanation of how the polarity of the voltage sent to the motor is reversed see our introductory article: Automatic Hen House Door Controller).
In order for the user to set the light level threshold at which day becomes night and night becomes day, a programming button is provided on the circuit board. When the ambient light level is at the level considered by the user to be the threshold, they press this button while powering on the controller to save that measured light level as the new threshold. The threshold is stored in permanent memory and is therefore not lost even when the controller is subsequently disconnected from the power.
Pictured above is a functionally identical controller, but which is built around an Arduino Pro Mini instead of the PICAXE-18M2 used in the original. The instructions for this controller are available here: Dawn Dusk Henhouse Door Controller Instructions.
If you need any type of door controller contact firstname.lastname@example.org with details of your exact requirements.