Chicken coops aren’t just cozy homes where the fowl can rest at night, they’re also vital protection from predators. In the United States, for example, coyotes are a serious threat to chickens and owners have to put real effort into keeping them at bay. A sturdy coop can provide good security, but the owner needs to herd to birds in and out each day, closing the door to lock them inside when it is dark. That’s a hassle, so lcamtuf built Chicken Squisher 3000. It is an automatic coop door that doesn’t squish chickens.
Over the summer, lcamtuf and their wife built a really serious chicken coop. They live in an area with legit predators, including grizzly bears and mountain lions, and cold winters, so they went all-out with the coop. It has double walls, double-pane windows, an electrified perimeter fence, and even electrical outlets inside for lighting and heating. By automating the door, lcamtuf can ensure the chickens remain safe, even if they aren’t home to close it up at night.
Chicken Squisher 3000 is an actuator that opens and closes the coop door. It can do so at the touch of a button or automatically based on light levels. Importantly, it has tunable stall torque settings. That’s where the device got its name, because lcamtuf can increase the torque just enough to reliably open and close the door, but not so much that the door poses a risk to the chickens.
A small DC motor with a worm gear swings the door via sliding rod, which eliminated the need for a complex linkage. An aluminum project box houses the electronics. The most important component is a Microchip AVR Dx 8-bit microcontroller (specifically, the AVR16DD14). It monitors light levels through a standard photoresistor and drives the DC motor through a DRV8231, which has current-sensing to enable stall torque settings. Other than that, it is just power and buttons.
The Chicken Squisher 3000 control box mounts just above the coop door, where lcamtuf can access it when overriding the default light-dependent behavior. And unless the local predators learn how to press the buttons, the chickens should remain safe and sound through the night.
