Reading from the sensor

Now that everything's connected, let's take a reading from our sensor. The DHT11 sensor gives us a 40-bit reading over the time span of 2 seconds. Timing and reading each bit can be a complex task. Fortunately for us, there are libraries present to make our lives easier.

Node.js does not have the required support for the DHT11 sensor, and we need to install the bcm2835 library in order to interface with the sensor.

To install the library, run the following commands:

wget http://www.airspayce.com/mikem/bcm2835/bcm2835-1.52.tar.gz
tar -xvzf bcm2835-1.52.tar.gz
cd bcm2835-1.52
./configure
make
sudo make check
sudo make install

Next, go to the ~/sensor-project/server directory and create a new file called obtain-readings.js.

Install the node-dht-sensor library:

npm install --save node-dht-sensor

Populate the contents of the obtain-readings.js file:

   ...