Each stepping stone will have one or two bundles of fibers sticking out of it (depending on the number of stars), which will then be run under the dirt to a couple of central lighting sources. Each bundle is lit by a single programmable RGB LED on an LED strip. All the strips are daisy-chained together along the path and ultimately controlled by a ESP32-based controller. That in turn is controlled over MQTT, which allows direct control of the color for each stone. Special animation patterns, such as a slow-cycle rainbow animation and the current zodiac sign can be activated over MQTT too.
To align the LED strips to the fiber ends, each fiber bundle is crimped with a unsheathed ferrule and then placed in a 3D printed housing that holds the strip at a fixed distance to the end of the fiber bundles.