Package Modules

class smartagro.smart.SmartAgro

Implemented After searching for a broker Instantiates an object which has sensors added to it then configures a broker. Sensors are attached added with corresponding topics Sensor Data is published and Actuator can be activated

activate_actuator(gpio_pin, state)

A function to activate or deactivate an actuator.

Parameters:

• gpio_pin (int) – GPIO pic of connected actuator.
• state (bool) – State whether it is on or Off

config_broker(broker='test.mosquitto.org', qos=0, port=1883, stream_schema='json')

Function to configure a new broker to be published to.

Parameters:

• broker – The url or ip address of the broker.
• qos – quality of service determining how many times message is sent. 0,1,2
• port – broker port in use. default 1883, ssl 8883
• stream_schema – the data stream schema used. Default is json

Returns:

mqtt client object

get_dht()

A function to get readings from the single wire DHT11 device.

Returns:Temperature and Humidity Readings

static on_connect(client, userdata, flags, rc)

The callback for when a connection is established with the server.

Parameters:

• client – Mqtt Client
• userdata – Authentication data
• flags – Connection indicators
• rc – status code of connection

static on_message(client, userdata, msg)

The callback for when a PUBLISH message is received from the server.

Parameters:

• client – MQtt client
• userdata – data used for authenticated connections
• msg – received message topic and payload in bytes

read_all()

A function to read all the values at once

Returns:A list of current moisture, light, temperature, humidity values

read_sensor(channel)

Reads sensor, publishes topic to broker, adds to active sensors

Parameters:channel – ADC channel to be read.

remove_device(device)

Function to remove device from published topics

Parameters:device (str) – Device Topic

Utilities Module. With several functions that are repeatedly used

smartagro.utils.cleanup()

GPIO.cleanup() and exit(0) for a graceful exit.

smartagro.utils.discover_i2c()

Scans address space and ports to discover connected I2C or SPI devices uses os i2cdetect for the 1 I2C port and also scans two SPI ports

smartagro.utils.find_broker()

Scan for online MQTT brokers then scan within network by checking online hosts then scanning for open MQTT ports

Returns:No return

smartagro.utils.gpio_init()

Function to initialize the GPIO pins, numbering system used and communication protocols. GPIO.BCM IS THE DEFAULT

smartagro.utils.read_analogue(channel, spi_device=0, baud=1350000)

Reads an analogue signal from the connected SPI ADC device and returns channel reading.

Parameters:

• channel (int) – ADC channel where sensor is connected.
• spi_device (int) – Either 0 or 1 as there are only 2 spi ports
• baud (int) – the bit rate, measured in bit/s clock rate used for device

Returns:

Raw 1024 bit ADC output data.

smartagro.utils.scan_network()

Ger the IP address other than the loopback IP that the device has been allocated by DHCP Scan subnet /24 of IP address to check for LAN brokers’ availability.

Returns:list of online devices responding to ICMP echo request using ping.

smartagro.utils.switch_actuator(gpio_pin, state)

Function to switch actuator ON or OFF

Parameters:

• gpio_pin (int) – The pin the fan relay (motor in demo) is connected to.
• state (boolean) – Boolean indicating whether fan is on or off.