Leaving the soil moisture sensor powered all the time leads to corrosion of

the probes. To account for this, this port breaks out Digital Pin D5 as the

power pin for the sensor, allowing the Photon to power the sensor, take a

reading, and then disable power, giving the probes a longer lifespan. The

moisture level can be read on Analog Pin A1.

More information about the Soil Moisture sensor can be found in the

Hookup Guide.

Soil or Water Temperature Sensor

In addition to soil moisture, you can also add a waterproof temperature

sensor. Whether you have a pond you’d like to monitor near your weather

station or you want to know if the ground is still frozen or not, this can be a

great addition to any weather station.

The waterproof version of the DS18B20 temperature senor is a go-to option

for many users looking to sense the temperature of various environments

that may not be so kind to electronics.

A port for this sensor is broken out along with the necessary 4.7K pull-up

resistor located between the Vcc and Signal lines. The Signal line is

connected to Digital Pin D4. Communicate with this sensor using the

OneWire and Dallas Temperature libraries.

SparkFun Soil Moisture Sensor

 SEN-13322

Temperature Sensor - Waterproof (DS18B20)

 SEN-11050

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