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
- 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!