Quick Start

In this Quick Start, you’ll learn how to initialize a new Node.js application, install the Node.js Application SDK and receive uplink messages from your application.

Setup #

Let’s install Node.js, create a Node.js project and install the Node.js Application SDK.

1. Download and install Node.js.

2. Create a new Node.js project:

   cd $HOME
   mkdir app
   cd app
   npm init
   

   Just press return to accept the default answer to any question asked.

3. Install and save the Node.js Application SDK as dependency:

   npm install --save ttn
   

Connect #

Next, we will write the script that requires the Node.js Application SDK and uses it to connect.

1. Create the main script and open it in your favorite editor:

   touch index.js
   open index.js
   

2. Import the Node.js Application SDK:

   var ttn = require("ttn")
   

3. In the Console, navigate to the application you’d like to connect to.

4. In index.js, enter the App ID and App Access Key:

   var appID = "foo"
   var accessKey = "ttn-account-v2.eiPq8mEeYRL_PNBZsOpPy-O3ABJXYWulODmQGR5PZzg"
   

   Here’s where you can find the values in the console:

   • For appID, copy the value for Application ID in the Application Overview box.
   • For accessKey, scroll down and then show and copy the value for default key in the Access Key box.

5. Add a listener for the connect and error events to test the connection:

   ttn.data(appID, accessKey)
     .then(function (client) {
       client.on("uplink", function (devID, payload) {
         console.log("Received uplink from ", devID)
         console.log(payload)
       })
     })
     .catch(function (error) {
       console.error("Error", error)
       process.exit(1)
     })
   

6. Run the script to test the connection:

   node .
   

   You should see something like:

   Received uplink from  office-hq
   { app_id: 'office-app',
     dev_id: 'office-hq',
     hardware_serial: '0004A30B001B61DE',
     port: 1,
     counter: 8717,
     payload_raw: <Buffer 01 e9 02 b1 01 69>,
     payload_fields: { celcius: 6.89, light: 489, sound: 361, state: { on: true } },
     metadata:
     { time: '2017-08-31T12:38:35.784566782Z',
       frequency: 868.3,
       modulation: 'LORA',
       data_rate: 'SF7BW125',
       coding_rate: '4/5',
       gateways: [ [Object], [Object], [Object] ] } }
   

   Use Ctrl+C to terminate the script.

   If you get an error it should say what is wrong:

   Error: Connection refused: Not authorized
   

🎉 Congratulations! Now you know how to receive messages in a Node.js script. Go build something! See API for all the functionality