We wanted a garden train around our deck and backyard to deliver popcorn and drinks for outdoor movie nights. We also wanted to make it approachable and usable for our toddler, as she loves trains. With that in mind, I decided to design it with two modes, a manual mode with a controller made just for her and an automatic mode via Home Assistant. Fairly quickly, we ruled out making a Bluetooth app or local webpage to control it. We wanted the experience to be phone free and the technology not to distract from the fun. So we went about designing an ideal control experience in our own physical controller. My daughter and I sat down and sketched our ideas together, what buttons do, what indicator lights it should have, etc. I wanted it to feel as analog as possible and be natural for small hands to hold, yet rugged enough not to break. We also wanted it portable, so she could wander with it and not be tied to a cord. One of the more exciting things I learned about was ESP Now, a direct way to communicate between two ESP microcontrollers using the WiFi radio. It does not require all the overhead of WiFi, has a quicker response time, uses less power, and messages receive a confirmation. The data rate is a lot slower, but I needed to send very small messages as needed. So we put an ESP8266 on the controller and an ESP32 in the train.
