Self locking doggy door for robot lawn mower

Hi, I have a robot lawnmower and I have a colourbond fence separating my front and back yard. I want to cut out a doggy door that stays locked (to keep the dog in) but opens as the robot lawnmower arrives from either side. I can hook it up to mains power but battery preferable and will need to be weather proof.

Open to ideas. I was thinking an rfid receiver mounted either side of the lock and the rfid chip on top of the mower, that trips in on the way past.

Really appreciate everyone here’s input and ideas.


Hi Xavier,

Welcome to the forum!!

RDIF or NFC sound like an excellent idea, you also might be able to use a magnetometer or camera based detection system.

Before jumping to detecting the robot I’d have a look to see if it will automatically pass through the gap if its opened briefly, the pathfinding algorithm will have a big influence on how you design the gate.

I’d love to see how this one goes!


Hi Xavier,

Just regarding the actuator for the doggy door - waterproof, high torque servos are available and might be an option. Here are a few examples :

They are on the expensive side for a single standard size servo but most of them have a significant torque rating (nearly 10+ (most hobby servos are typical less than and metal gear trains which may be useful given you are lifting a section of colour bond fencing. I would stick to Hitec or Savox as they may have replaceable gear trains.

No matter what servo you choose (if you do happen to go the servo route), it would be good to ensure you have a push-pull system for the servo as this takes some of the load off and prevents the servo from twisting type fatigue you may get from a single arm joint. Push-pull systems have been used in RC Aeromodelling for many years to alleviate stress on weaker servos, but are less present these days due to improved servo technology.