Building an Automated Smart Plant Watering System
An IoT precision irrigation ecosystem designed to monitor and hydrate studio plants automatically during multi-day commercial film shoots and travel.
The Problem: Studio Vegetation During Location Shoots
As a filmmaker and creative director, productions often pull me out of the studio for days or weeks at a time on set. Studio plants either suffered from chronic underwatering or flooded roots from well-meaning overcompensation. Cheap battery-operated timers from retail stores lacked soil feedback and often caused messy overflows.
This project solves it with closed-loop precision: it only waters when the root zone soil moisture dips below an exact calibrated threshold, and dispenses measured milliliter doses.
Engineering Highlights
- Corrosion-Free Capacitive Sensing: Unlike cheap resistive moisture probes that dissolve within two weeks due to galvanic DC electrolysis, capacitive sensors measure dielectric permittivity with no exposed metal traces touching moist soil.
- Anti-Siphoning Peristaltic Dosing: Submersible fountain pumps create an unintentional gravity siphon that drains water tanks when the pump stops. Peristaltic rollers pinch the silicone tube shut at all times, providing absolute anti-siphon safety over studio camera gear.
- Low-Power Deep Sleep Architecture: The ESP32 sleeps at 15 µA, wakes up every 60 minutes to power the sensor rail via an isolated MOSFET (preventing continuous soil electrolysis), reads the ADC, computes moisture, waters if required, publishes telemetry over Wi-Fi, and returns to sleep.
- Home Assistant & Telegram Alerts: Instant push notifications when the water reservoir is running low or when soil temperature spikes.
While the sensor blade is insulated, the top electronic components (NE555 timer and resistor ladder) are vulnerable to water splashes. Always coat the top circuit board with silicone conformal coating and heat-shrink tubing before plunging into soil.