Last modified 4 years ago Last modified on 01/13/15 17:38:41

WWKoruza deployment user guide

This is the guide for deploying the World Wide KORUZA experiment with generation 5 devices. It takes you step-by-step to deploying the FSO link and test equipment on your location.


For deploying the experiment you require the following:

  • WWKoruza experiment set as provided by Institute IRNAS Rače
  • Weather station WH1080 or similar
  • Deployment location prepared as described in Installation details
  • A laptop computer with WiFi capability and able to establish SSH connections

Step 1: Unpacking and testing

The experimental set you have received consists of:

  • Two experimental sets (KORUZA unit attached with a test box)
    • KORUZA unit with RED lid on the back is referred to as unit A
    • KORUZA unit with BLUE lid on the back is referred to as unit B
  • Two sets of mounting brackets
  • Test box contains:
    • Configured and programmed test router
    • Plastic bag containing
      • screws for the box lid
      • mains cable socket
    • set of three WiFi antennas

Verifying that you have received all necessary parts, connectivity to the nodewatcher system need to be verified and you familiarize with the system prior to deployment on the experimental location.

First you need to register with the nodewatcher system so you can receive the experimental nodes in management and credentials for accessing them via ssh, enabling you to control every individual unit:

  1. Create an account if you do not happen to have one, allowing you to use node database.
    1. Visit node database and log in.
    2. Let Luka know your username, for the nodes to be transferred to you.
    3. Select My Nodes.

Follow by connecting every individual unit to mains with provided power supply adapters, mind that there is no need for units to be aimed at eachother at this point. Then add the uplink to every units and test the connectivity to the network:

  1. Attach the WiFi antennas to the router and place it back in the box
  2. Attach the mains to the power supply, alternatively you can provide 12V directly to the split terminal, disconnecting the mains power supply
  3. Connect the your local network to WAN port of every test router
    1. Network must provide DHCP address
    2. Router establishes a VPN link to the wlan slovenija network, generally finds its way through most firewalls
    3. After connecting WAN uplink, wait up to 2min for the connectivity to establish, shown by the rightmost light on router turning on (two twisted arrows)
  4. To unit A (red lid) attach the weather station to USB port 2 and place the indoor unit within the test box.

Assuming you have the two experimental units connected to the system, connect your laptop computer to the WiFi network SSID, you will be now able to ssh into test routers and control test devices.

Find out IP addresses of both units:

  1. Visit node database and log in.
  2. Select My Nodes.
  3. Note the IP address of the unit.
  4. Select Edit node and scroll down to see the password

Establish ssh connections to both units, you are prompted with the standard linux command prompt.

Now you can run the koruza-control interactive terminal for controlling every unit by running the command:


This is the real-time control and monitoring interface for the unit, required during installation. You receive real-time updates on all measurements with 1Hz rate and control the unit with keys, closing it with esc.

Commands required during installation:

  • arrow-keys move the laser beam in the associated direction (distance a single press moves the unit determined below)
  • u - very coarse movement
  • o - coarse movement
  • i - fine movement (default)
  • l - toggle green laser (default off)

Initially toggle the green laser and verify you see it, leave the units connected and contact Luka to configure them for your distance and remotely update to last version.

Step 2: Desktop testing

Prior to deployment of the system, familiarize yourself with the operation by setting up the link at about 5m distance indoors, feasible simply by placing units on desk at an either side. This step as well insures that operation is correct and units are ready for deployment.

To establish the link, follow these steps:

  1. Apply power to both units, place them at some distance apart, 5m sufficient.
  2. Log in via the console, turn on green lasers and aim the units by manually moving them.
  3. Perform fine adjustment via the console until about 20dBm power is received.

The link is aligned by pointing the center of the green laser spot produced by one unit to the green laser on the opposite unit. The green laser is mounted above the lens in the center as shown on the diagram below.


Step 3: Installation

This guides you to install the units on the outdoor experimental location and establish the link.

  1. Make sure units are updated, contact Luka
  2. Mount the units on your locations, provide power and network.
  3. Manually aim the unit using metric 13 wrench by adjusting the mechanical mount.
    1. Wait for a cloudy day or an evening, so you will be able to see the green laser well.
    2. You should be able to adjust the aiming to within 10cm at 30m distance or 30cm at 100m distance with this method.
    3. Once completed use the controls via ssh to accurately aim the green laser at the opposite green laser.


Mechanical mount must be in such orientation, that the arm of the assembly is parallel with KORUZA and the mounting plate that attaches to the wall or a horizontal pole is perpendicular to the KORUZA. Only in this orientation the two adjustment points can be used to coarsely aim KORUZA with manual adjustment. Firstly adjust the horizontal direction (azimuth) and secondly the elevation.

Note the mount orientation on the image!


Please note the green laser beam diameter at a distance is significantly greater then the KORUZA unit, so try to place the beam center just above the lens, where the green laser aperture is. At this point the laser should turn off at the link will be established. As it is possible there is some small miss-alignment between the communication laser beam, control the unit to move slightly in all directions until the link is established. Once established, observe the local and received optical power (position ssh windows side by side) and adjust until observing the maximal value.

Service steps

Documentation on servicing units for the some technical problems that may arise due to transport and other causes.

Loose lens

The optical lens is tightly fitted to the 3D printed part and acetone is applied around the edge to melt the 3D printed part and hold the lens in place. If sufficient force is exerted on the lens, it may become loose and move towards the inside of the unit, when shaking you may hear it rattle.

This problem can be easily fixed using the following steps, requiring tools:

  • acetone (proper acetone!)
  • about 25mm wide suction cup, used in cars generally as well as in smartphone repair kits

Follow these steps to repair the lens:

  1. Manipulate the lens in the vertical orientation
  2. Clean the lens with a fine cloth or paper tissue
  3. Mount the suction cup to the center of the curved side of the lens
  4. Manipulate the lens to tightly fit to the mounting ring
  5. Pull on the suction ring and apply a very small amount - few drops of the acetone, with the unit pointing upwards. Acetone should only flow around the edge, without a large amount of it collecting on the top of the lens.
  6. Wait a few minutes for the acetone to vaporize.
  7. Turn the unit so it points downwards, let it set for a few hours.
  8. Unit may need to be re-calibrated afterwards.

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Opening back cover - loose spring

The back cover of the KORUZA unit houses the control electronics and gives you access to the alignment stage. Stepper motor is held towards micrometer screw with spring. The spring is mounted to the motor with a small plastic ring super-glued to the motor. Transport stress may cause the spring to get loose.

The problem can be easily fixed and the spring placed back on the motor following these steps, requiring tools:

  • Torx T10 screwdriver
  • Super-glue
  • Pliers

Follow these steps to open up the unit:

  1. Unscrew two torx screws
  2. Remove silicon sealant
  3. Carefully pull the cover off
  4. The processor is mounted in the cover, the control shield connects with cables to KORUZA.
  5. Hold the cover with one hand and the control shield with the other, make sure you hold it next to the pins. Slowly pull apart.
  6. You have now free access to the inside of the unit.
  7. Check that the motor shaft sits inside the coupler.
  8. Take the loose spring, apply super-glue to the plastic ring.
  9. Hold the spring slightly compressed with pliers and insert to the motor, align it to concentric with the motor shaft.
  10. Plug the processor back to the control shield, mind the orientation. Shield and processor boards are of the same size.
  11. Connect to the unit via ssh and use arrow keys to move the motors, check they are rotating.
  12. Put the cover in the original position and add torx screws.
  13. Re-apply silicone to the cover before putting the unit outside.

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Enclosure dis-assembly

The KORUZA unit is housed within an aluminum enclosure, this instructions show you how to take the core out of the enclosure. To put it back in, apply these steps in reverse order. the motor with a small plastic ring super-glued to the motor. Transport stress may cause the spring to get loose.

Tools required:

  • Torx T10 screwdriver
  • HEX (Allen) key 3mm
  • Flat electrical screwdriver

Follow these steps to open up the unit:

  1. Open the back cover, instructions above
  2. Disconnect power, ethernet and USB cables
  3. Remove silicon sealant in front of the unit, where it touches the casing
  4. Remove blue screw covers
  5. Unscrew 4pcs M4 screws around the front side
  6. Point the front side of the unit towards the desk, push the core part by hand from the back side, so it drops out
  7. The core is now separated from the enclosure
  8. Perform fixes as desired
  9. Follow these steps in reverse
  10. Re-apply silicone to the cover before putting the unit outside

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