Soil Moisture Sensor

Compact Dual-Output Soil Moisture Sensor Module

Meet the compact, versatile soil moisture hygrometer module designed to empower Arduino projects, DIY robots, and smart irrigation systems. Powered by an LM393 comparator, this board delivers reliable readings with two output options—digital and analog—so you can implement both simple on/off watering and nuanced moisture control across multiple zones.

Key features that set it apart

• Dual outputs for flexibility — use the digital DO signal for straightforward on/off decisions or the analog AO output for continuous moisture readings, enabling both threshold-based irrigation and precise soil sensing within the same module.
• Adjustable sensitivity — a blue potentiometer lets you tailor the moisture threshold to your soil type and plants, whether you’re in sandy loam or dense clay.
• Broad voltage compatibility — operates from 3.3V to 5V, making it compatible with a wide range of microcontrollers and development boards, including popular Arduino setups.
• Compact, sturdy design — a small PCB (approximately 3 cm × 1.6 cm) with fixed bolt holes for quick, secure installation in pots, planter boxes, or robot chassis.
• Visual indicators — red power indicator and a green digital output indicator provide quick, at-a-glance status during prototyping and testing.
• Reliable sensing — LM393 comparator-based stability for dependable readings as soil moisture changes, even in fluctuating conditions.
• Flexible pack options — available in 5- or 10-piece assortments to outfit multiple planting zones or multiple project iterations without frequent reorders.

Ideal use cases

• Automated irrigation for pots, raised beds, and small gardens — trigger watering only when moisture falls below your chosen threshold.
• Arduino projects and DIY robotics where soil sensing informs decisions — for example, a smart rover that waters plants as it moves.
• Educational kits and STEM experiments demonstrating sensor integration, analog vs digital signals, and threshold-based control.
• Greenhouse or terrarium setups requiring consistent moisture management without constant monitoring.

Wiring, calibration, and practical use

Connect the module to your microcontroller as follows: VCC to 3.3V–5V, GND to ground. Use the DO output for a digital signal (high/low) and the AO output for an analog moisture value. Turn the blue potentiometer to set the moisture threshold for the digital output; as soil dries or wets, the DO signal will switch accordingly. Read the AO output with an ADC-capable input to capture precise moisture levels and translate those readings into watering actions in your code.

Tip: The compact form factor with fixed bolt holes makes installation in pots, planter boxes, or robot chassis quick and repeatable, while the built-in indicators simplify debugging during development and testing.