sensors - Working with Sensors

The sensors module provides a collection of classes to interact with sensors, such as temperature, light, and soil moisture sensor.

Temperature/Humidity Sensor

class sensors.TemperatureSensor(port[=3])

Allows reading temperature and humidity information from the Grove Temperature Sensor based on DHT11. We recommend that this sensor be connected to Port 3, which is the default for this class. The port parameter defines which port the sensor is connected to.

TemperatureSensor.get_temperature(celsius[=False])

Returns the temperature reading in Fahrenheit. If celsius is set to True then the celsius temperature will be returned.

Note

This temperature sensor offers a resolution of 1 degree Celsius. If you want more accurate readings, please try the pro version below.

TemperatureSensor.get_humidity()

Returns the relative humidity in percentage.

TemperatureSensor.show_data(screen, line)

Shows the temperature (in Fahrenheit) and relative humidity on the specified screen object on the specified line. Also returns a tuple of the same temperature in Fahrenheit and relative humidity to avoid repeated readings on the sensor.

Example

from sensors import TemperatureSensor()
t = TemperatureSensor() # defines a temperature sensor at default port (Port 3)

t.get_temperature() # returns the Fahrenheit value
t.get_temperature(True) # returns the Celsius value
t.get_humidity() # returns the humidity value

Temperature/Humidity Sensor Pro

class sensors.TemperatureSensorPro(port[=3])

Allows reading temperature and humidity information from the Grove Temperature Sensor Pro based on DHT22 (AM2302). We recommend that this sensor be connected to Port 3, which is the default for this class. The port parameter defines which port the sensor is connected to.

TemperatureSensorPro.get_temperature(celsius[=False])

Returns the temperature reading in Fahrenheit. If celsius is set to True then the celsius temperature will be returned.

Note

This temperature sensor offers a resolution of .1 degree Celsius.

TemperatureSensorPro.get_humidity()

Returns the relative humidity in percentage.

TemperatureSensorPro.show_data(screen, line)

Shows the temperature (in Fahrenheit) and relative humidity on the specified screen object on the specified line. Also returns a tuple of the same temperature in Fahrenheit and relative humidity to avoid repeated readings on the sensor.

from sensors import TemperatureSensorPro
t = TemperatureSensor(3) # defines a temperature sensor pro at default port (Port 3)

t.get_temperature() # returns the Fahrenheit value
t.get_temperature(True) # returns the Celsius value
t.get_humidity() # returns the humidity value

# shows temperature/humidity data on the oled screen
from displays import OledScreen

screen = OledScreen(6)
t.show_data(screen, 1)

Light Sensor

class sensors.LightSensor(port[=6], address[=0x29])

Allows reading lux values from the Grove Digital Light Sensor based on the TSL2561 I2C light sensor. The port parameter cannot be any other number than 6, and the sensor can be connected to the board through an I2C hub. The address parameter assigns the I2C address of the light sensor. 0x29 (41) is the default for the Grove sensor. The Adafruit version has a default of 0x39 (57).

LightSensor.get_lux()

Returns the light intensity reading as lux.

Hint

Useful lux values:

• Sunlight: 107,527
• Full Daylight: 10,752
• Overcast Day: 1,075
• Very Dark Day: 107
• Twilight: 10.8
• Full Moon: .108

LightSensor.show_data(screen, line)

Shows the light intensity reading in lux on the specified screen object on the specified line. Also returns the same lux reading to avoid repeated reading on the sensor.

Example

# The following code reads light value every 5 seconds,
# and if it's too dark (lux < 100), prints a warning message

from sensors import LightSensor
import time

l = LightSensor()

while True:
    lux = l.get_lux()

    if lux < 100:
        print("Too Dark!")

    time.sleep(20) # wait for 20 seconds

Moisture Sensor

class sensors.MoistureSensor(port[=4])

Allows reading moisture values from the Grove Moisture Sensor. The port parameter cannot be any other number than 4, because the sensor is analog.

MoistureSensor.get_moisture(port[=4])

Returns the raw moisture reading.

Warning

Because the moisture sensor is analog, the values of the sensor readings might vary from case to case. It is a good idea to calibrate the sensor by experimenting on the soil.

MoistureSensor.show_data(screen, line)

Shows the raw moisture reading on the specified screen object on the specified line. Also returns the same raw moisture reading to avoid repeated reading on the sensor.