Air Quality monitor using Arduino for indoor and outdoor pollution monitor – Circuit Schools
#include <Wire.h>
#include <Arduino.h>
#include “MQ135.h”
#include <Adafruit_BME280.h>
#include <Adafruit_Sensor.h>
#define LENG 31 //0x42 + 31 bytes equal to 32 bytes
unsigned
char
buf
[
LENG
]
;
int
PM01Value
=
0
;
//define PM1.0 value of the air detector module
int
PM2_5Value
=
0
;
//define PM2.5 value of the air detector module
int
PM10Value
=
0
;
//define PM10 value of the air detector module
float
h
,
t
,
p
,
pin
,
dp
;
char
temperatureFString
[
6
]
;
char
dpString
[
6
]
;
char
humidityString
[
6
]
;
char
pressureString
[
7
]
;
char
pressureInchString
[
6
]
;
Adafruit_BME280
bme
;
// I2C
void
setup
(
)
{
Serial
.
begin
(
9600
)
;
delay
(
10
)
;
Serial
.
println
(
)
;
if
(
!
bme
.
begin
(
)
)
{
Serial
.
println
(
“Could not find a valid BME280 sensor, check wiring!”
)
;
while
(
1
)
;
}
}
void
loop
(
)
{
if
(
Serial
.
find
(
0x42
)
)
{
//start to read when detect 0x42
Serial
.
readBytes
(
buf
,
LENG
)
;
if
(
buf
[
0
]
==
0x4d
)
{
if
(
checkValue
(
buf
,
LENG
)
)
{
PM01Value
=
transmitPM01
(
buf
)
;
//count PM1.0 value of the air detector module
PM2_5Value
=
transmitPM2_5
(
buf
)
;
//count PM2.5 value of the air detector module
PM10Value
=
transmitPM10
(
buf
)
;
//count PM10 value of the air detector module
}
}
}
static
unsigned
long
OledTimer
=
millis
(
)
;
if
(
millis
(
)
–
OledTimer
>
=
1000
)
{
OledTimer
=
millis
(
)
;
Serial
.
(
“PM1.0: “
)
;
Serial
.
(
PM01Value
)
;
Serial
.
println
(
” ug/m3″
)
;
Serial
.
(
“PM2.5: “
)
;
Serial
.
(
PM2_5Value
)
;
Serial
.
println
(
” ug/m3″
)
;
Serial
.
(
“PM10 : “
)
;
Serial
.
(
PM10Value
)
;
Serial
.
println
(
” ug/m3″
)
;
Serial
.
println
(
)
;
MQ135
gasSensor
=
MQ135
(
A0
)
;
float
air_quality
=
gasSensor
.
getPPM
(
)
;
Serial
.
(
“Air Quality: “
)
;
Serial
.
(
air_quality
)
;
Serial
.
println
(
” PPM”
)
;
Serial
.
println
(
)
;
h
=
bme
.
readHumidity
(
)
;
t
=
bme
.
readTemperature
(
)
;
t
=
t*
1.8
+
32.0
;
dp
=
t
–
0.36
*
(
100.0
–
h
)
;
p
=
bme
.
readPressure
(
)
/
100.0F
;
pin
=
0.02953
*
p
;
dtostrf
(
t
,
5
,
1
,
temperatureFString
)
;
dtostrf
(
h
,
5
,
1
,
humidityString
)
;
dtostrf
(
p
,
6
,
1
,
pressureString
)
;
dtostrf
(
pin
,
5
,
2
,
pressureInchString
)
;
dtostrf
(
dp
,
5
,
1
,
dpString
)
;
Serial
.
(
“Temperature = “
)
;
Serial
.
println
(
temperatureFString
)
;
Serial
.
(
“Humidity = “
)
;
Serial
.
println
(
humidityString
)
;
Serial
.
(
“Pressure = “
)
;
Serial
.
println
(
pressureString
)
;
Serial
.
(
“Pressure Inch = “
)
;
Serial
.
println
(
pressureInchString
)
;
Serial
.
(
“Dew Point = “
)
;
Serial
.
println
(
dpString
)
;
Serial
.
println
(
“………………………………………..”
)
;
}
}
char
checkValue
(
unsigned
char
*
thebuf
,
char
leng
)
{
char
receiveflag
=
0
;
int
receiveSum
=
0
;
for
(
int
i
=
0
;
i
<
(
leng
–
2
)
;
i
++
)
{
receiveSum
=
receiveSum
+
thebuf
[
i
]
;
}
receiveSum
=
receiveSum
+
0x42
;
if
(
receiveSum
==
(
(
thebuf
[
leng
–
2
]
<
<
8
)
+
thebuf
[
leng
–
1
]
)
)
//check the serial data
{
receiveSum
=
0
;
receiveflag
=
1
;
}
return
receiveflag
;
}
int
transmitPM01
(
unsigned
char
*
thebuf
)
{
int
PM01Val
;
PM01Val
=
(
(
thebuf
[
3
]
<
<
8
)
+
thebuf
[
4
]
)
;
//count PM1.0 value of the air detector module
return
PM01Val
;
}
//transmit PM Value to PC
int
transmitPM2_5
(
unsigned
char
*
thebuf
)
{
int
PM2_5Val
;
PM2_5Val
=
(
(
thebuf
[
5
]
<
<
8
)
+
thebuf
[
6
]
)
;
//count PM2.5 value of the air detector module
return
PM2_5Val
;
}
//transmit PM Value to PC
int
transmitPM10
(
unsigned
char
*
thebuf
)
{
int
PM10Val
;
PM10Val
=
(
(
thebuf
[
7
]
<
<
8
)
+
thebuf
[
8
]
)
;
//count PM10 value of the air detector module
return
PM10Val
;
}
