NMEA0183 Wi-Fi Configuration

Configuration

Whilst the gateway is ready to go out of the box for most users, there are a number of configuration parameters that may need to be set up. Configuration is done through a web interface, so you need to connect to the device's Wi-Fi network and point your browser at the device

Throughout this section, the default settings for the device are shown in [square brackets]. If you want to ensure that you start configuration from a known state, or you are having problems connecting to the device, perform a factory reset by pressing and holding the reset button until it stops flashing, and then release. This clears all of your settings, and puts everything into its factory defaults.

Connect to the Device's Wi-Fi Network

On your phone, tablet or laptop, enable Wi-Fi and open the Wi-Fi settings. Select the SSID (or name) of the gateway's Wi-Fi network [TeamSurv-nn-nnnnnn where nn-nnnnnn is the device's serial number, on a label on the device] and enter the password [teamsurv]. This will connect you to the network - you may get a warning that there is no internet connection, which you can ignore.

Opening the Configuration Web Site

There are two ways to enter the configuration web site - manually or using the QR code printed on the label.

QR Code

If you have an app that can read QR codes, and you are using the default IP address of the device [192.168.4.1], then you can simply take a photo of the QR code, and your QR app will open your web browser at the configuration home page.

Manual

Open your web browser, and enter the IP address of the device as the URL [http://192.168.4.1]. This will open the configuration home page.

Configuration Home Page - System Status

NMEA 0183 WiFi Gateway status page

The home page shows the status of the system.

The counters give the numbers of NMEA sentences sent and received over the wired port, and over the TCP and UDP Wi-Fi ports. and the number of web page requests and responses.

Uptime gives the time (in hh:mm:ss) since the device was last powered up or restarted.

System info gives the serial number, the firmware version, and the amount of free memory on the heap.

SSID gives the SSID or network name being used - either that built in [TeamSurv-nn-nnnnnn] or, if connected to a router, the SSID of the router.

Wi-Fi says whether the device is operating as an Access Point (AP) or as a client to another AP, e.g. a router on the boat. It also says how many devices are connected to the gateway's Wi-Fi network.

The screen refreshes every 5 seconds, or pressing the Refresh  button forces a refresh.

Configuration takes you through to the configuration menu, after a log-in page.

Login Page

To get to the configuration pages, you need to enter the device password [teamsurv]. It is recommended that you change this to your own password in the Misc menu. If you have forgotten the password, you can reset it to the default by using the reset button to do a factory reset.

NMEA0183 WiFI gateway configuration menu

This menu gives access to all of the configuration functions:

  • Home returns you to the home page. Don't forget to click on Apply first, if you have made any changes.
  • NMEA lets you change the data rate of the NMEA port
  • Wi-Fi lets you configure the Wi-Fi connection
  • TCP and UDP lets you configure the TCP and UDP connections
  • Misc lets you change the password to get in to the configuration pages, and the diagnostics
  • Apply saves any changes you have made, and restarts the device. If you don't select Apply, then any changes made will be lost.
  • Restart discards any changes you may have just made, and restarts the device. You can also restart the device by a short press on the reset button.
  • Factory Defaults deletes all of your settings in the device, and restarts it with everything reset to the factory defaults. You can also restore the factory defaults by holding and pressing the reset button until the reset LED stops flashing, and then releasing it.

NMEA

NMEA 0183 Wi-Fi gateway NMEA configuration page 

Select the data rate of the wired NMEA port [4800bps]. Both input and output run at the same speed. Standard NMEA0183 runs at 4800bps, whilst high speed NMEA0183, used by default by many AIS devices, runs at 38400bps. Some devices, particularly those not intended for the marine market, may run at other speeds.

Click on OK to keep your changes, or Cancel to discard them. Remember that changes are not committed to the device until you click on the Apply button in the main menu.

Wi-Fi

NMEA0183 Wi-Fi gateway WiFi configuration page

Before going into the specific settings, some general networking information.

Access Point (AP) Mode

If your boat does not have a Wi-Fi router on it, then the gateway will set up its own Wi-Fi network, operating as an Access Point (AP) that your phones, tablets etc. need to connect to over Wi-Fi to get the NMEA data. In this case, you can select a Wi-Fi channel that is unused by other networks in range (not so important at sea, but it can be when in the marina). The SSID (or network name) is fixed [TeamSurv nn-nnnnnn where nn-nnnnnn is the serial number] but you can (and should) change the password, otherwise anyone in range can log in with the default password, and send and receive NMEA data to your network (this may sound innocuous enough, but it may include sending you false GPS data, or sending commands to your autopilot). The gateway will have a static IP address, and although the subnet mask [255.255.255.0] and IP address [192.168.4.1] can be changed there is seldom any need to do so.

Router Client Mode

If your boat has a router or a network on board, then it generally pays to connect the gateway to this. It means that your phones, tablets etc. can access all of the network facilities without having to switch between Wi-Fi networks, and also if there is a router giving access to the internet then they can access the internet at the same time as receiving NMEA data from the instruments.

In this configuration, the router sets your Wi-Fi channel, and you must enter the SSID (network name) and password of the router (you can quickly enter the SSID by tapping or clicking on it in the list of networks, which copies it into the SSID field). In general it is best to use a fixed IP address, as then apps always know where to find the NMEA data, in which case you need to go into the router configuration, and in the DHCP settings reserve the IP address you want to use in the gateway, and make a note of the router's subnet mask. Then, in the gateway configuration, tick Use Static IP, and enter the IP address and subnet mask. If you decide to use a dynamic IP address then just untick Use Static IP, and the DHCP server in the router will configure everything, but you won't know the IP address of the gateway that your apps want to connect to, and it may be changed over time by the router, so this is only recommended if your apps can use the gateway's tools to find it and configure themselves to connect to it.

Settings

These have been segregated for AP mode, Client with static IP address, and client with  dynamic IP address.

Setting Access Point Router client
IP Address Fixed Fixed Dynamic
Wi-Fi Mode AP Client Client
Channel Enter the channel number you want to use [1] Set by router
SSID Fixed as TeamSurv-nn-nnnnnn Enter to match router
Password Enter your own value [teamsurv] Enter to match router
Use static IP Ticked Ticked Unticked
IP Address Enter your own value [192.168.4.1] Enter to value reserved in the router Set by router
Subnet mask Enter your own value [255.255.255.0] Enter to match the value used in the router Set by router

Click on OK to keep your changes, or Cancel to discard them. Remember that changes are not committed to the device until you click on the Apply button in the main menu.

Wi-Fi Networks

This lists all Wi-Fi networks in range, giving the network name or SSID, the Wi-Fi channel used, whether or not the network is encrypted, and the RSSI or signal strength  - a less negative number means a stronger signal. If operating in AP mode, then this helps you select a channel with minimal congestion. If in client mode, you should see your router's network listed here, and clicking on its name will copy it into the SSID field.

TCP and UDP

NMEA 0183 WiFi gateway TCP and UDP configuration page

The device can broadcast or multicast over UDP to any number of devices, and support up to 3 simultaneous TCP connections. If the apps you want to use support TCP, then that is generally the best choice, and you can disable UDP as this can slow down the Wi-Fi network. If you need to use UDP, then multicast is more secure than broadcast, though not all apps support it so you may have to use broadcast. Leaving TCP running has no detrimental effect on the network if it is unused. For a discussion on the pros and cons of the UDP and TCP protocols, you can read this blog entry.

Whichever protocol you use, or even if you use both, you need to have an IP address and a port number. For TCP, the IP address is simply that assigned to the gateway, and the value is displayed on the screen (go to Wi-Fi to change it). For UDP, there are rules on ranges of IP addresses to be used, which differ for broadcast and multicast; if you want to change the defaults, you probably know to refer to the relevant RFCs to ensure you use a correct address. Both the TCP and the UDP multicast addresses also need to be entered into your app, though if you use UDP broadcast then the app doesn't need to know the IP address.

For the port number, this must match the port number you enter into the app when configuring it, and also you can expect problems if you use a port number used by something else, e.g. 80 for web browsing. The standard value is 10110, but quite a large number of apps use a different, fixed port number, and if this is the case then you have to set the gateway to use this port number as well. Whilst UDP and TCP connections can have different port numbers, all TCP connections use the same port number, so by using an app with a non-standard port number you may find that the choice of other apps you can use is restricted to those that either use the same port number, or those where the port number can be edited.

Because a TCP connection is point to point, when no longer needed it must be closed down properly, otherwise the gateway and/or the device running the app thinks it is still needed, and keeps it open. Some situations where the connection may no longer be needed, but is not closed down properly, are:

  • a user running an app on his phone leaves the boat and walks down the dock. Once out of range the connection cannot be used, but the gateway doesn't know what has happened, so keeps the connection open
  • on an iPhone or iPad, if the user has been running a nav app connected to the gateway, and then brings up another app, then unless the nav app detects this and closes down the network connection it is closed forcibly by the operating system in a way that leaves both the app and the gateway thinking they are connected. As you can imagine, this ends up in a mess when the nav app is brought back up again, so it needs to be closed, and both it and the gateway restarted. Unfortunately there are many apps out there that handle this badly.
  • the app may crash on the phone, and although the network connection is cleared down on the phone, the gateway isn't always told o close the connection.

The only way to clear these orphaned connections is to restart the gateway, and as the gateway only supports 3 simultaneous connections they need to be conserved carefully. This is made possible through the time out option.If this is enabled (i.e. set to a value other than 0) then two things happen: if no data is received from the app in the specified time, the connection is closed in the gateway; and also the gateway will send a "keep alive" dummy NMEA message to the app at least twice in the time-out period, so the app knows that the gateway is still up and running. If your app can send data to the gateway, then it is well worth enabling the timeout facility to avoid orphaned TCP connections forming and clogging up the gateway.

Click on OK to keep your changes, or Cancel to discard them. Remember that changes are not committed to the device until you click on the Apply button in the main menu.

Misc

NMEA0183 Wi-Fi gateway miscellaneous settings page

The main item here is you can change the password to enter the configuration settings. It is good practice to do this, as it minimises the risk of someone changing the device settings.

You can also switch on the broadcast of diagnostic messages, and set the IP address used to broadcast them. This is not required for normal operation, and you should only do this if instructed to do so by technical support.

Click on OK to keep your changes, or Cancel to discard them. Remember that changes are not committed to the device until you click on the Apply button in the main menu.