Key Engineering Features

• True Digital Capacitive Sensing: Ditching the noisy, drifty analog peak-detectors of standard cheap soil sensors. The FR4 PCB blade acts as the timing capacitor for an industrial-grade TLC555IDR oscillator. It outputs a raw, clean frequency directly to the ESP32's hardware Pulse Counter (PCNT) for flawless, high-resolution moisture data.
• Zero-Leakage "Parasitic" Power: The 555 timer is powered directly by an ESP32 GPIO pin. The ESP32 wakes up, powers the sensor, takes a reading, and kills the power before going back to sleep. Sensor quiescent current: 0.0µA.
• Panelized 3-in-1 Design: The Radio PCB, Power Hat, and Sensor Blade are all designed to be manufactured on a single 100x100mm panel connected by mouse-bites to save on fabrication costs.
• Mortise & Tenon Assembly: The Sensor Blade features a custom "tenon" tab that slots perfectly into the main Radio PCB and is soldered directly at a 90-degree angle, requiring zero wires.
• Pogo-Pin Power Hat: Handles the mechanical shear force of a plunging outdoor sensor by using through-hole Pogo Pins (spring-loaded contacts) rather than weak SMD conical springs.
• Low-Voltage Optimized: Features an ultra-efficient 573nm Yellow-Green LED that requires only ~2.0V to light up. It will reliably flash in "Config Mode" even when the 3x AA batteries are nearly dead. Includes a precision 1% 220kΩ voltage divider for highly accurate battery monitoring.