Smart Plant

Arduino IDE

Arduino Uno Rev3

Plant Watering Kit

tape

EC11 Encoder

<html><body>SMART_FICUS 🌱 An Arduino-based automatic plant watering system with an OLED display, rotary encoder menu, and per-plant moisture profiles. Built around an SSD1306 display, a DHT11 temperature/humidity sensor, a capacitive soil moisture sensor, and a relay-driven water pump. Features Live OLED dashboard — cycle through pages showing an animated plant graphic (with weather effects for hot/cold conditions), soil moisture %, temperature/humidity, raw sensor readout, and the active plant's settings. Rotary encoder navigation — interrupt-driven for responsive menu control; press to enter the settings menu, turn to adjust values. Per-plant profiles — Ficus, Succulent, and Fern each have their own dry/wet moisture thresholds, pulse duration, and rest interval, all editable from the on-device menu and persisted to EEPROM. Pulsed watering — waters in short bursts with a rest interval between them instead of one continuous pour, so slow-draining soil has time to absorb moisture before the next check. Safety cutoffs A maximum-duration timeout aborts a watering cycle (and flags it on the display) if the moisture reading never reaches the wet threshold — guards against an empty reservoir, a dislodged probe, or a clogged line. Skips new watering pulses below 15°C, since cold soil absorbs water more slowly and would otherwise waterlog rather than hydrate. A hardware watchdog timer force-resets the board if the main loop ever stalls, with the relay pin defaulting to OFF as the very first action on boot/reset. Hardware Component	Notes Arduino Uno (or compatible)	ATmega328p-based SSD1306 128x64 OLED	I2C, address 0x3C Capacitive soil moisture sensor	Analog output → A0 DHT11 temperature/humidity sensor	Digital pin 5 Rotary encoder (KY-040 or similar)	CLK→2, DT→3, SW→4 Relay module	Signal → pin 7; active-LOW (drive LOW to energize) Small DC water pump	Powered through the relay's switched contacts Wiring notes Power the pump from a separate supply from the Arduino/OLED, sharing only a common ground through the relay's switched side — this avoids the pump's current draw sagging the same rail powering your logic. Put a flyback/rectifier diode across the pump motor terminals. Brushed DC pump motors generate continuous electrical noise while running, which can corrupt the I2C bus and hang the display indefinitely (the standard Wire library has no timeout). This one part fixes it. If you still see occasional display corruption, also try a bulk decoupling capacitor (100–470µF) across 5V/GND near the pump/relay, and make sure the relay module has its own flyback diode across the coil. Calibration Every capacitive moisture sensor reads differently. Before relying on this for an actual plant: Open the settings menu and note the raw ADC value with the probe completely dry (out of soil/water) and fully submerged in water. Set each plant profile's dryLimit a bit below your dry reading and wetLimit a bit above your wet reading, leaving margin at both physical extremes. Watch the live moisture % for a few days and nudge the thresholds to taste — a Ficus, Succulent, and Fern all want very different watering behavior. <figure><img src="https://projects.arduinocontent.cc/48abf31b-63a8-4320-9c8a-bb9998c46662.png"/><figcaption>Circuit Diagram</figcaption></figure></body></html>

Smart Plant

Keep your plant alive on vacation