ssgs

Sensor Seal Gateway Server

The Sensor Seal Gateway Server (SSGS) Node.js Module allows you to create a customized Sensor Seal Gateway Server that can perform customized processing of Sensor Seal measurements.

Installing

Ensure you have Node.js version 14 or later installed and then follow the steps below:

1. Create a package

   npm init
   

2. Set the package type to "module"

   npm pkg set type="module"
   

3. Install SSGS

   npm i ssgs
   

Basic Usage Example

Import the SSGS module and use it as follows:

import SSGS from 'ssgs';

// Create a new Sensor Seal Gateway Server that listens on UDP port 1818
const server = new SSGS(1818, client => {
    // Called when a new client connects
    console.log('New client connected');

    // Print all updates received from the client
    client.onupdate = update => {
        console.log(`\nReceived Sensor Seal update via gateway ${SSGS.uidToString(update.viaGatewayUID)}:`);
        console.log(`Sensor Seal UID: ${SSGS.uidToString(update.sensorSealUID)}`);
        console.log(`Temperature: ${update.temperature} deg C`);
        console.log(`Vibration: ${update.vibration} mm/s^2`);
        console.log(`Speed: ${update.rpm} rpm`);
        console.log(`Voltage: ${update.voltage} mV`);
        console.log(`Update ID: ${update.updateID}`);
    };
});

Port Forwarding

If you want gateways to be able to connect to your SSGS server from outside your local network, you need to forward external incoming traffic from UDP port 1818 (or the port the gateway was configured to connect to) to your SSGS server. It is recommended to keep all ports as 1818 unless you require multiple servers with the same public IP address.

Setting Up Gateways

1. Connect the gateway to the internet via an ethernet cable. Power can be supplied to the gateway via Power over Ethernet (PoE) or the terminals.
2. Navigate to https://gateway.sensorseal.com and sign in to your Gateway Manager account.
3. Select the gateway you wish to configure.
4. Choose SSGS as the Connectivity Type
5. Enter the hostname of your SSGS server. This could be ssgs.example.com or 192.168.1.40 for example.
6. Enter the port of the SSGS server. This should be kept as 1818 unless you specifically changed the server's listening port.
7. Click Generate Key to generate a new key for this gateway.
8. Make note of the Gateway UID and key as these will be required later.
9. Click Save Changes.

Configuring which gateways are allowed to connect

There are two ways in which gateways connecting to the server can be authorized or rejected:

1. An authorized.json file can be created in the root of the project directory. This file should contain a JSON object with a single property called authorized_gateways which is an array of objects with the following properties:
   • description: A description of the gateway. This is optional.
   • uid: The UID of the gateway as a string of hexadecimal bytes, optionally separated by spaces.
   • key: The key of the gateway as a string of hexadecimal bytes, optionally separated by spaces. An example of this is shown below:

{
    "authorized_gateways": [
        {
            "description": "This is an example gateway",
            "uid": "4d ec 5d fa",
            "key": "1a 02 d7 2e 8f f3 78 7f 31 19 e6 4d ec 5d fa 7b b3 42 a3 66 e5 18 28 df 97 ae ef a7 67 4d 62 aa"
        }
    ]
}

2. The onconnectionattempt callback can be set after creating the SSGS server. This callback is called when a gateway attempts to connect to the server and can be used to authorize or reject the connection. The callback is passed the gateway's UID, source address, and source port. It should return the key of the gateway if the connection is to be authorized, or null if the connection is to be rejected. For example:

server.onconnectionattempt = async (gatewayUID, remoteAddress, port) => {

    // Check if the gateway is authorized and return the key if it is
    // These two functions must be implemented by you
    if (gatewayIsAuthorized(gatewayUID)) {
        return getGatewayKey(gatewayUID);
    }
    
    return null; 
};

Starting the Server

Start the server with

node index.js

where index.js is the name of your project's entry point.