The problem
A normal pet flap is always open. This door stays closed and opens only when a pet inside is trying to leave. It also tracks whether the pet has gone out or come back in.
How it works
Two ESP32s over ESP-NOW
- Question
- How do the sensing side and the door actuator communicate?
- Method
- Two ESP32 boards send messages directly over ESP-NOW, Espressif's low-latency peer-to-peer protocol, with no Wi-Fi router involved.
- Why
- The door responds fast, and there's no dependence on a home network.
Direction sensing with IR break beams
- Question
- Is the pet entering or leaving?
- Method
- Infrared break-beam sensors at the opening. The order in which the beams are broken gives the direction of travel.
- Why
- Break beams are simple and reliable, and they don't need a collar tag.
Sliding door mechanism
- Question
- How does the door open and close?
- Method
- A sliding door, opened when a pet is detected inside trying to leave.
Build
CAD: sliding mechanism
Photo: electronics / wiring
Diagram: sensing → ESP-NOW → door logic
What's next
- Finish the door mechanism and integrate the electronics.
- Test detection reliability with real pets.