Creating the Arduino sketch

Let's now build a simple sketch to test our sensor via Bluetooth. We are going to build a sketch so that it measures the temperature and humidity from the DHT sensor when a given command is received on the serial port.

We start by including the DHT library so that we can use the DHT11 sensor:

#include "DHT.h"

Then, define the sensor's pin and type:

#define DHTPIN 7
#define DHTTYPE DHT11

Note that if you are using a different DHT sensor, you will need to modify the code here. For example, if you are using a DHT22 sensor, simply type the following:

#define DHTTYPE DHT22

You will also need to define an instance of the DHT sensor and to send the sensor type and sensor pin as an argument:

DHT dht(DHTPIN, DHTTYPE);

In the setup() function of the sketch, you will have to initialize the DHT sensor's instance and start the serial connection:

dht.begin();
Serial.begin(115200);

We need to use a speed of 115,200 bauds here instead of the standard 9600 bauds...