AirQuality source code is confusing

[DOSSTONED]

I currently working on Intel Edison, and have Grove Air Quality Sensor v1.1

Problem1 recreation:
Downloading the source, and install to Arduino library(Arduino IDEdownloaded from intel). Open the example, start Verify. And errors:

Arduino: 1.5.3-Intel.1.0.4 (Windows NT (unknown)), Board: “Intel® Edison”
AirQuality_Sensor.ino:30:4: error: expected constructor, destructor, or type conversion before ‘(’ token

It seems that IDE doesn’t know about the function: ISR(TIMER2_OVF_vect).
I googled it and found it, it’s a kind of interrupt, and the source is just make sure every 2 seconds update the value.
So I rewrote this part using loop, delay 0.1 seconds and update every 20 times. But compiler reports:

Arduino: 1.5.3-Intel.1.0.4 (Windows NT (unknown)), Board: “Intel® Edison”
Arduino\libraries\AirQuality_Sensor\AirQuality.cpp: In member function ‘void AirQuality::init(int)’:
Arduino\libraries\AirQuality_Sensor\AirQuality.cpp:80:5: error: ‘TCCR2A’ was not declared in this scope
TCCR2A=0;//normal model
^
Arduino\libraries\AirQuality_Sensor\AirQuality.cpp:81:5: error: ‘TCCR2B’ was not declared in this scope
TCCR2B=0x07;//set clock as 1024*(1/16M)
^
Arduino\libraries\AirQuality_Sensor\AirQuality.cpp:82:5: error: ‘TIMSK2’ was not declared in this scope
TIMSK2=0x01;//enable overflow interrupt
^
Arduino\libraries\AirQuality_Sensor\AirQuality.cpp:84:9: error: ‘sei’ was not declared in this scope
sei();
^

So I commented out them, and recompile, finally it works!
Guys, can you run the examples without modification?

Problem2:
In the example source, it called airqualitysensor.init(14); in setup(). So this sensor should be connected to A0.
But AirQuality.cpp’s void AirQuality::init(int pin) function is built-in first_vol=analogRead(A0);//initialize first value which means it just read A0 even if you set to A1 pin.
This should not a problem, due to the value would be changed after 2 seconds(why 122 means 2 seconds?)
And why use interrupts to update the value?

[viswa]

Sorry for delayed reply. Air Quality library currently works on AVR based Arduino. This is the reason for many compiler errors.

All these are AVR GCC specific code :

//init the timer 
TCCR2A=0;//normal model
TCCR2B=0x07;//set clock as 1024*(1/16M)
TIMSK2=0x01;//enable overflow interrupt
Serial.println("Test begin...");
sei();

The sensor itself is just an Analog output. The Arduino Libray provided sets certain thresholds to detect the quality of Air. I think the original author used periodic sampling to average-out the output from the sensor. This is also to filter the raw analog value.

We will improve the existing documentation for Grove Air quality-sensor

Let me know if you need any further information.

[herts]

I wanted use Grov- Air Quality Sensor V1.3 with udoo neo with Base shield v2 (connect A2) , but cannot use example from Seeedstudio site and github. Error (ISR (TIMER2_OVF_vect ). Why? Thanks.