Monitor Suhu dan Kelembaban memakai Ubidots

Grafik di atas menunjukkan suhu dan kelembaban di kamar saya.

Untuk menghasilkan grafik di atas saya memakai pengukur suhu DHT11 yang di akses melalui Arduino Pro Mini.
Kemudian data di kirim ke website Ubidots melalui router MR3020 yang sudah di flash dengan OpenWRT.

Okay tanpa basa-basi lagi akan saya sharingkan beberapa hal berikut.

Sketch Arduino - nya :

//
// FILE: dht11_test1.pde
// PURPOSE: DHT11 library test sketch for Arduino
//

//Celsius to Fahrenheit conversion
double Fahrenheit(double celsius)
{
return 1.8 * celsius + 32;
}

// fast integer version with rounding
//int Celcius2Fahrenheit(int celcius)
//{
// return (celsius * 18 + 5)/10 + 32;
//}

//Celsius to Kelvin conversion
double Kelvin(double celsius)
{
return celsius + 273.15;
}

// dewPoint function NOAA
// reference (1) : http://wahiduddin.net/calc/density_algorithms.htm
// reference (2) : http://www.colorado.edu/…/weather_stati…/Geog_site/about.htm
//
double dewPoint(double celsius, double humidity)
{
// (1) Saturation Vapor Pressure = ESGG(T)
double RATIO = 373.15 / (273.15 + celsius);
double RHS = -7.90298 * (RATIO - 1);
RHS += 5.02808 * log10(RATIO);
RHS += -1.3816e-7 * (pow(10, (11.344 * (1 - 1/RATIO ))) - 1) ;
RHS += 8.1328e-3 * (pow(10, (-3.49149 * (RATIO - 1))) - 1) ;
RHS += log10(1013.246);

// factor -3 is to adjust units - Vapor Pressure SVP * humidity
double VP = pow(10, RHS - 3) * humidity;

// (2) DEWPOINT = F(Vapor Pressure)
double T = log(VP/0.61078); // temp var
return (241.88 * T) / (17.558 - T);
}

// delta max = 0.6544 wrt dewPoint()
// 6.9 x faster than dewPoint()
// reference: http://en.wikipedia.org/wiki/Dew_point
double dewPointFast(double celsius, double humidity)
{
double a = 17.271;
double b = 237.7;
double temp = (a * celsius) / (b + celsius) + log(humidity*0.01);
double Td = (b * temp) / (a - temp);
return Td;
}

‪#‎include‬ 

dht11 DHT11;

‪#‎define‬ DHT11PIN 2
boolean ack = false;

void setup()
{
Serial.begin(9600);
Serial.println("DHT11 TEST PROGRAM ");
Serial.print("LIBRARY VERSION: ");
Serial.println(DHT11LIB_VERSION);
Serial.println();

}

void loop()
{
// Serial.println("\n");

int chk = DHT11.read(DHT11PIN);
/*
Serial.print("Read sensor: ");
switch (chk)
{
case DHTLIB_OK:
Serial.println("OK");
break;
case DHTLIB_ERROR_CHECKSUM:
Serial.println("Checksum error");
break;
case DHTLIB_ERROR_TIMEOUT:
Serial.println("Time out error");
break;
default:
Serial.println("Unknown error");
break;
}
*/
// Serial.print("Humidity (%): ");
Serial.println((int)DHT11.humidity);

// Serial.print("Temperature (C): ");
Serial.println((int)DHT11.temperature);

delay(2000);
}
//
// END OF FILE
//

Di Router MR3020 -nya :

1. Edit /usr/bin/suhu.sh

#!/bin/sh

cat /dev/ttyUSB0 > /tmp/log.txt &
sleep 2
killall cat

api_key="b7adf5968db2140dcea136c458c4be4a6440a3ec"
deviceID="55a7382a7625422d983169d3"
deviceID2="5613482a7625ab22d983169a4"

value=`cat /tmp/log.txt | tail -n 1` ‪#‎post‬ data Suhu
value2=`cat /tmp/log.txt | head -n 1` #post data Kelembaban

‪#‎obtain‬ a token
my_token=`/usr/lib/lua/ubidots.lua -token $api_key)`
echo "Token: "$my_token

#post Temperature data to Ubidots
/usr/lib/lua/ubidots.lua "-post" $api_key $deviceID $value

sleep 1

#post Humidity data to Ubidots
/usr/lib/lua/ubidots.lua "-post" $api_key $deviceID2 $value2

2. Pakai cronjob jalankan script diatas setiap menit
* * * * * /usr/bin/ubidots.sh > /dev/null

Untuk tutorial lebih lengkap saya persilahkan menuju ke website : http://www.ediy.com.my/index.php/projects/item/121-ubidots-lua-openwrt-router-ubidots-real-time-data-monitoring .

Selamat mencoba !