Automatic Chicken Coop Door at Sunrise and Sunset

Predators strike at dusk. This build calculates sunrise and sunset every day with the astral library and drives a linear actuator through a two-relay H-bridge, with a reed switch to confirm the door really closed.

Video tutorial

▶ FloweringElbowWatch on YouTube ↗

Video by FloweringElbow, embedded from YouTube. The written steps below are our own and match the parts list.

Mission steps

1. Build the door

   A sliding vertical door in a guide rail, connected to a 12 V linear actuator with built-in limit switches.

2. Wire the H-bridge

   Two relays reverse the actuator's polarity: one for open, one for close. Never energize both — the code enforces it.

3. Add the reed switch

   Mount it so the magnet meets it only when the door is fully closed.

4. Install astral

   pip install astral in a venv and set your latitude, longitude and time zone.

5. Alert on failure

   If the reed switch does not confirm closed one minute after the close command, send a phone notification.

Code

import datetime, time
from zoneinfo import ZoneInfo
from astral import LocationInfo
from astral.sun import sun
from gpiozero import OutputDevice, Button

TZ = ZoneInfo("America/New_York")
home = LocationInfo("Coop", "US", "America/New_York", 27.27, -80.35)   # set your own lat/lon
up = OutputDevice(17, active_high=False); down = OutputDevice(27, active_high=False)
closed = Button(22)

def move(relay, other, secs=25):
    other.off(); time.sleep(0.2); relay.on(); time.sleep(secs); relay.off()

while True:
    now = datetime.datetime.now(TZ)
    s = sun(home.observer, date=now.date(), tzinfo=TZ)
    should_open = s["sunrise"] <= now < s["sunset"] + datetime.timedelta(minutes=30)
    if should_open and closed.is_pressed:
        move(up, down)
    elif not should_open and not closed.is_pressed:
        move(down, up)
    time.sleep(60)

Tip: test every script on the bench before installing it in a moving machine.

Questions