Codeby La Văn Thịnh (vthinh-la) · GitHub · open hardware
A small robot character that reads soil moisture and changes its facial expression to show when a plant is getting dry. The face is the interface for the plant's water level.
Mostly software for reading a sensor and drawing a face, with light wiring for a sensor and display.
Based on "Robot planter that shows soil moisture" on Afterware: https://afterware.xyz/p/robot-planter-that-shows-soil-moisture
Write MicroPython code for an ESP32 that reads a capacitive soil moisture sensor on an analog pin every 10 seconds. Map the reading to three states (wet, ok, dry) and draw a simple cartoon face on a small OLED display that changes expression for each state. Smooth the readings and add a calibration constant for dry and wet air values.
Estimates based on the original write-up.
CrazyScience built a small robot companion for a houseplant. A moisture sensor in the soil feeds a reading to the robot, and the robot's expression changes to show how thirsty the plant is. The aim is a reminder that sits on the desk where the plant is, so watering doesn't depend on remembering a schedule.
The source is a short blog post that points to the full Instructables write-up. The post describes the robot as cute and shows real-time moisture levels through facial expressions. It does not list the boards, display or sensor used, so those details are left to the original project page.
The post is brief on method. The project page is the place to check the wiring, enclosure and code.