HYDROMEA Luma X User manual

a fast, long-range, optical underwater communication system
Manual
Version 1.8 for Firmware Version 1.4
9/2023

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Contents
1 Introduction ............................................................................................................................ 4
2 Initial setup ............................................................................................................................. 4
2.1 Windows 10 setup ............................................................................................................ 5
2.2 LUMA X setup ................................................................................................................... 6
2.3 Setting the IP address ....................................................................................................... 7
2.4 Testing the communication ............................................................................................. 8
2.5 Transmitting data ............................................................................................................. 9
3 Modem configuration ............................................................................................................. 9
3.1 Main page ....................................................................................................................... 10
3.2 Parameters page ............................................................................................................ 10
3.3 Status page ..................................................................................................................... 14
3.4 IP address change page .................................................................................................. 16
3.5 Communication test ....................................................................................................... 16
4 Modem firmware upgrade using LumaConf ......................................................................... 17
5 Maintenance ......................................................................................................................... 19
6 API ......................................................................................................................................... 19
6.1 API parameters ............................................................................................................... 19
1.1 API usage examples using Python .................................................................................. 25
7 Electrical and software Characteristics ................................................................................. 26
8 Mechanical Characteristics ................................................................................................... 27
9 Errata ..................................................................................................................................... 29

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WARNING:
 bright LED light source, do not look directly at emitter
 a few people may experience epileptic seizures when
viewing flashing lights

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1 Introduction
The LUMA X is an optical modem for fast, reliable wireless underwater communication. Each
LUMA X is a full transceiver and thus capable of half-duplex communication (transmission and
reception).
Note: this manual applies to the LUMA X as well as the LUMA X-UV. Throughout the manual
all references to LUMA X also apply to LUMA X-UV except for when there is an explicit
differentiation.
Note: this manual is only valid for the v1.4 firmware version of the LUMA X modem. You can
check your firmware version on the main webpage of your modem (see chapter 0 of the
manual to access the LUMA X webpage). If your modem firmware is outdated, please contact
Hydromea in order to get the latest version of the LUMA X firmware.
2 Initial setup
Note: while submerging the LUMA X, a small number of bubbles may come out of the
pressure compensation vent at the connector end of the modem. When LUMA X is back on
the surface a small amount of water may come out of the vent.
For normal operation of the LUMA X, only the Ethernet cable is used for the communication.
The serial cable is only used for factory reset and firmware upgrade of the modem.
The LUMA X comes preconfigured to forward data, automatically select the transmission speed
and the amount of LEDs used for transmission depending on the distance between the modems
and the amount of ambient light. They do not require configuration for normal use, however
this setup guide will allow you to check if the optical communication link is well established and
enable you to change the configuration of the modem if necessary.
Note: As the LUMA modems form a bridge, they should not be connected to the same cabled
network (i.e. do not plug both modems into the same switch). Doing so may lead to a loop in
the network, where one LUMA picks up traffic from the other LUMA and feeds it back to the
switch, flooding the network with packets. The modems should be connected to two separate
cabled networks as shown in Figure 1.

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Figure 1: Typical initial test setup. The IP addresses of the modems are not critical but useful to differentiate them
2.1 Windows 10 setup
The following steps explain how to set an IP address on your Windows 10/11 PC
 go to → Settings → Network & Internet → Ethernet (in left column) → Network and
Sharing Center (in right column) → Change adapter settings (in left column) → right click
on Ethernet adapter → Properties → select Internet Protocol Version 4 (TCP/IPv4) →
Properties
 set the address as shown in Figure 2
Verifying the IP address setting:
 Open a command line: → Windows PowerShell
Figure 2: Windows 10 network settings

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 Type: ipconfig /all
 You should see the IPv4 address setting shown in Figure 3
Figure 3: IPv4 address settings
On the remote PC, repeat the procedure, but set the IP address to 192.168.102.103.
2.2 LUMA X setup
Once the host computer’s IP address is set correctly the connection to the LUMA X can be
tested.
 Connect only one LUMA X to a computer via an Ethernet connection using Hydromea’s
power/data cable.
 Connect the LUMA X to a suitable supply voltage (12 V – 36 V) using Hydromea’s
power/data cable.
 Optional step: to test that the IP address has been set correctly, the computer should
now be able to ping the LUMA X on its default IP address 192.168.102.101 and the
modem should respond to it.
o Windows 10: Open a command line: → Windows PowerShell
o enter ping 192.168.102.101
 Open a browser, and enter 192.168.102.101 into the address field. The LUMA X web
interface main page should appear (see Figure 5)

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All LUMA X have their IP address factory-set to 192.168.102.101.
You can change the IP address of the modem through the web interface.
2.3 Setting the IP address
For the initial test, modem (1) can remain at the default IP address. The other modem (2) must
be set to a new IP address that is unique within the subnet. For the initial example, we use
192.168.102.102.
 Plug in only modem number (2) and navigate your browser to 192.168.102.101
 Click on the menu item “IP change”
 Enter the new IP address 192.168.102.102 (for the second modem)

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 Click “Set”. The new IP address is now temporarily applied, and the page will reload
showing the new IP address:
 To store the new setting to flash memory, click “Save”. The modem is now set to the
new IP address.
2.4 Testing the communication
To test communication by exchanging messages between modems, the modem’s firmware
provides a simple interface as shown in Figure 4. Connect the first modem to the operator PC,
and connect the second modem to a remote PC (e.g., a second laptop, or an ethernet-capable
remote device). The operator PC should be set to IP address 192.168.102.100. The remote PC
should be set to IP address 192.168.102.103 (this IP address is given as an example for the
initial setup – it can be chosen freely within the same subnet).
Power up the modems on both sides. The boot-up takes up to 10 seconds.
Access the “Comm. Test” page from the operator PC,
http://192.168.102.101/test_comm.html
and from the remote PC,
http://192.168.102.102/test_comm.html
Messages can be exchanged from one modem to another and should be displayed on the page.
Note that ambient light, artificial light sources (fluorescent office lighting, LED lamps, screens,
sunlight) may interfere with the optical channel and disrupt communication. If a link cannot be
established, try to turn off lights, or cover the modems with an opaque sheet of cardboard or
cloth while ensuring line of sight between the modems. Ideally the modems should be
separated by at least 1 meter, as the receivers may saturate at very close range.

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Figure 4: messaging interface for modem-to-modem communication
2.5 Transmitting data
On the operator PC, open a Shell, and type:
ping 192.168.102.103
If everything is configured correctly, the modems will visibly flash with blue light, and the ping
will show the response from the remote PC.
The optical link is now ready and will forward any ethernet traffic from one side to the other
side.
3 Modem configuration
This chapter will describe the modem configuration in detail.
LUMA X modems come preconfigured allowing for easy optical communication and do not
need additional configuration.
However, for more specific use cases, where limiting the number of LEDs used for transmission
or limiting the modem to a specific optical speed, these can be changed in the “Parameters”
section of the LUMA X web interface.
The web interface is also useful to get some statistics about the modem itself, such as the
throughput, number of packets received and lost as well as the supply voltage of the modem.

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3.1 Main page
Figure 5: main page of the web-based configuration-UI
This page provides information about the current revision of the hardware, firmware and API. It
also provides the firmware’s SHA and the unique processor ID.
3.2 Parameters page
Figure 6: parameter page of the web-based configuration-UI