Soil Moisture Sensor Kit – Light-Up Plant Water Indicator

This DIY soil moisture sensor kit from Lectrify lets you build a light-up flower that tells you when a plant needs water. The flower's roots measure the resistance of the soil, and an LED switches on when the soil gets too dry. It is a Level 2 kit for beginners, students and hobbyists who want to learn real electronics while solving an everyday problem.

Key features

• Teaches how an NPN transistor works as a switch
• Covers resistors, variable resistance and the potentiometer
• Builds a voltage divider circuit
• Uses soil conductivity to sense moisture: wet soil keeps the LED off, dry soil turns it on
• Adjustable dial lets you calibrate the trigger level for each plant

In the box

• 1 x NPN transistor
• 1 x 220Ω resistor
• 1 x 100K potentiometer
• 1 x red LED
• Circuit board

Tools required but not included: soldering iron, solder wire, wire cutters and a Phillips screwdriver. Find more beginner projects in our learn-to-solder collection.