Building a $250 Automatic Chicken Coop Door Opener for $100

Backstory

My parents raise chickens in their backyard and wanted a way to automate opening and closing the door to their chicken coop. All of the products I found on Amazon Prime (door + controller) were quite expensive—and overpriced in my opinion—so I decided to see whether I could reverse engineer the functionality at a cheaper price point.

Challenges

This project had several requirements and design constraints that made things tricky. The biggest one was the budget. Since our budget was $100 and the door we planned on buying was $50 online, I only had $50 for the automation/door controller for this build. Here is what I needed to figure out: 

• Needs to be battery operated and last for at least two weeks (14 days)
• Needs to open in the morning and close in the evening, after all birds have entered the coop
• Needs to cost $50 or less to assemble
• Needs to be weatherproof

If price weren't a constraint, I immediately would have chosen a cellular IoT board like the Particle Electron or Boron ($50). Connectivity to the cloud provides several advantages:

• Remote/manual control of the door via the cloud
• Internet connectivity provides clock times that are always in sync

  • Clock crystals in microcontrollers tend to be inaccurate for long-term Applications
  • RTC modules can accomplish this but require an external coin cell battery and cost $15 (a significant chunk of my budget)
• Ability to create a user interface on web/mobile

  • Gives some transparency to the tech, which would otherwise be a black box to my parents

Time to Build!

However, I also needed a motor to move the door up and down. I decided to use a sensor-based approach to opening and closing the coop door. I ended up with a pretty simple parts list:

• Arduino UNO

  • Low-cost programmable microcontroller with barrel-jack access for power
• AA battery pack to male barrel-jack

  • Powers the Arduino
• 10K resistor, wires, photoresistor

  • For a voltage divider circuit to serve as a daytime/night-time sensor
• ULN2003 Stepper Motor

  • Plug & play, as far as motors go, these work with the Arduino stepper motor libraries
• Titan Incubators Chicken Coop Door

  • The door
• Small salad container from the local grocery store (free)

  • Weatherproof container for electronics

Once I had all the parts ordered, it was just a matter of putting everything together. Check out the video at the beginning of this post to see me assembling this thrifty automatic chicken coop door!