At the end of part 2, our pet had a face, reflexes, and a serious philosophical problem: no memory. You could pet it a hundred times, reboot the board, and it woke up with the same hardcoded stats, feeling nothing, remembering nothing. Every day was its first day.
Today the pet gets what every Tamagotchi fundamentally is: a state machine with feelings. Its hunger, energy and mood become rows in DynamoDB. A Lambda decides how a snack or a shake changes them. And, the part I find genuinely delightful, EventBridge Scheduler makes time pass, so the pet gets hungry overnight while the device is completely powered off. When you flash the firmware Monday morning, the pet wakes up, asks the cloud "what did I miss?", and gets visibly sad about the answer.
In this article, I will walk you through the whole brain: the data model (it's one table with one row per pet... gloriously boring), the decay math that makes offline time count, IoT rules that invoke Lambda without a single line of polling code, and the loop back down to the device.
Code for this article: git checkout article-3.
The architecture, now with a brain
