Sensor

Purpose

The functionality of the Sensors rely on two main components which are implemented in the core functions:

• EspSensor super-class
• Physical Sensors which implement the EspSensor and form the basis for the sensor modules by defining the physically measurable quantity

EspSensor super-class

Functionality

The EspSensor class exposes two methods which are later implemented by the physical sensor classes.

void setValue(float value)

void updateMQTT()

This method is used for sending the captured values through MQTT to AWS.

Both functions are separated in order to prevent timing problems due to a delay when sending Data to AWS. So all sensor values are read first, then they sent over MQTT.

Physical Sensors

The following physical entities are already implemented:

• Temperature
• Humidity
• Barometric pressure
• Illuminance
• Gas concentration

Functionality

All physical sensor implement the EspSensor as their super-class. The idea behind a structure like this is to adapt the sub-class in a manner that there is a class for every physical entity. Later, an object of the specific physical sensor class (e.g. 'Temperature') can be used to set the current measured value.

This standardizes the measurement of a physical quantity and facilitates a later analysis of the acquired data of a type.

Adding a physical sensor

If there is the need for a new physical sensor, comply to the form of the other implementations. The following Pre processors need to be adapted:

#define UNIT        "new_physical_unit"
#define SENSOR_TYPE "sensor_type"
#define MQTT_TOPIC  "/sensor_type"