Plant Watering Alarm Capacitive Soil Moisture Sensor

This is a plant watering alarm – as simple as that. You put it into the soil near a plant and it emits a tiny chirp when the soil is dry, reminding you to water the plant. It uses capacitive humidity sensing as opposed to resistive humidity sensing, this means, it does not make an electric contact with the soil, avoiding electrode corrosion and soil electrolysis and resulting in better accuracy and longer battery life.
Special care has been taken not to make it yet another source of annoyance – This sensor will be silent when it’s dark and will restrict itself from making too much noise.
The alarm level can be set for each plant individually. As water is consumed by the plant, it will detect the low moisture level and will start to emit rare short chirps. As more water evaporates, it will increase the alarm rate. This sensor can detect if it’s day or night by measuring the amount of ambient light and will not make noise when it’s dark.
Soil moisture sensing
Light sensing
Temperature sensing
Reset chip
I2C address change
Deep sleep