Arduino Library for PM2.5 AQI Particle Sensor : ZPH02

Compatible with all Microcontroller Like Arduino, Esp8266, ESP32 etc..

Description

ZPH02 is a simple Arduino library for Reading AQI moving averages Or Duty Cycle from the sensor ZPH02.

This sensor operates as a pwm source with duty cycle as a output variable in the default mode.

The user specifies the interval (number of data points) for the moving average in the constructor. When the begin(pin) function is called, an array is dynamically allocated to hold the number of data points in the interval. This array is never deallocated, and the user should call begin() only once (for a given zph02 instance) in setup or other initialization code. Dynamic allocation is used strictly with the intent of creating the proper size array for the user's purposes, and not to free up the memory at a later point. It is strongly recommended that zph02 objects remain allocated as long as the code is running. Failure to observe these guidelines can result in heap fragmentation, crashes and other undesired behavior.

Constructor

zph02(float interval)

Description

Defines a zph02 object where the average is calculated using interval data points.

Syntax

zph02(interval);

Parameters

interval: The number of data points to use when calculating the moving average. (float)

Returns

None.

Example

zph02 aqi_sensor(10);    // use 10 data points for the moving average

Methods

begin(pin)

Description

Initializes a zph02 object. Call begin(pin) once and only once for any given zph02 instance. See comments in the Description section above.

Syntax

begin(5);

Parameters

GPIO Pin

Returns

None.

Example

aqi_sensor.begin(5);

getAqi(bool getdutycycle)

Description

Adds a new data point to the moving average. Returns the new moving average value. Until the interval array is filled, the average is calculated from those data points from AQI of the sensor output pulses, i.e. a fewer number of points than defined by the constructor.

Syntax

###Read AQI getAqi(false); ###Read Duty Cycle getAqi(true);

Parameters

True = DutyCycle, No = AQI Moving Average

Returns

The new moving average value OR DutyCycle

Example

// Get Duty Cycle from Sensor
float dutycycle = aqi_sensor.getAqi(true);

// Get AQI Moving Average from Sensor
float AQI = aqi_sensor.getAqi(false);

getAvg()

Description

Returns the current moving average value without adding a new reading.

Syntax

getAvg();

Parameters

None.

Returns

The moving average value. (float)

Example

float formulaResultAvg = aqi_sensor.getAvg();

reset()

Description

Restarts the moving average. Zeros the interval array and associated data.

Syntax

reset();

Parameters

None.

Returns

None.

Example

aqi_sensor.reset();

##This library is written with the help of : https://github.com/ThingEngineer/movingAvg Written by Jack Christensen
Mar 2012