node-dht-mqtt

A simple node.js app for Raspberry Pi that:

• reads temperature and humidity from your DHT11 - DHT22 sensor
• publish it to an MQTT broker of your choice

Requirements

• Raspberry Pi (tested on Model B and Zero W). Note: the project dependencies node-dht-sensor and BCM won't work on other devices, so npm -i will fail. Look at the debug section for additional info.
• DHT11 or DHT22 sensor
• node and build tools

Usage

SSH to your Raspberry Pi and:

• install Broadcom BCM Library (for additional info: http://www.airspayce.com/mikem/bcm2835/ ) :

# example of installation
# download bcm
wget http://www.airspayce.com/mikem/bcm2835/bcm2835-1.56.tar.gz

# unpack
tar -xzvf bcm2835-1.56.tar.gz

# cd and compile
cd bcm2835-1.56/
./configure
make check
make install

• clone repo and install

# install required dependency node-gyp globally
npm install node-gyp -g

# clone repo
git clone https://github.com/lombax85/node-dht-mqtt.git
cd node-dht-mqtt

# install project dependencies (if you face permission errors add --unsafe-perm)
npm i --unsafe-perm

# copy configuration template
cp config.js.example config.js

• edit config.js

• test it:

node app.js

you should see a console message with Temp and Humidity

• add crontab to publish every minute

* * * * * node /path/to/node-dht-mqtt/app.js

Config:

let config = {
    mqtt_data: {
        username: 'xxx',            // your mqtt username
        password: 'xxx',            // your mqtt password
        port: 10109,                // mqtt port
        host: 'mqtt://url.com',     // mqtt url
        topic: 'topic/name'         // topic name, simple string
    },
    sensor_data: {
        dht_version: 11,            // Your DHT sensor version, 11 or 22
        pin_number: 17              // the GPIO you connected the DHT to. See below image
    },
    other_options: {
        timeout: 5000               // after this timeout the script will exit
    }
};

module.exports = config;

For the GPIO pinout see this image:

Debug

Since node-dht-sensor and BCM won't compile if you are not on a Raspberry Pi, for debugging purposes on your PC, there is an automatic debug function. If the node-dht-sensor package is not found, you will see a console message and TEST data will be emitted (99 C° and 1% humidity).