Serverless AI in my backyard

Recently I added some cool stuff to my home automation platform using computer vision, serverless code and MQTT. When you have kids, you know they leave doors open. This does not have to be a big problem, except when there are bikes unlocked in the backyard. After all: we don't want them to be stolen! I have a Home Automation platform running, but I don't want to equip my bikes with sensors.