Deploying sensors

Sensors are attached to trees based on GPS coordinates determined during deployment planning. Afterwards, they can be "forgotten". They do not need any further maintenance. Any software updates to the sensors are then done remotely.

The assigned use locates in the forest using the Deployment app a tree closest to the GPS coordinates set for a sensor. Using the sensor's QR Code, the actual position of the sensor is saved to the Silvanet Cloud. Once a sensor is successfully linked to its actual position in the Silvanet Cloud, it can then be installed on a tree.

The sensor nodes are designed with a loop which can be used with a treenail (or crop wire) to attach the sensor to a tree.

Deployment guidelines

• Deploy the sensor on the tree 3 m above the forest floor.

  We recommend installing the sensor on the tree trunk approximately 3 meters above the level of the forest floor. At this height, the device is most sensitive to fire detection and it obtains an increased amount of light on its solar cell. Furthermore, at this height it avoids disturbances from most human and animal interactions.

• Sensor should face towards the sun (at 12:00 noon).

  Use a compass to identify true South (in the northern hemisphere) or true North (in the southern hemisphere). This maximizes the amount of light that hits the sensor's solar cell during the day.

• Use the spacer to keep the sensor away from the tree bark.

  A 2cm spacer is provided to deploy the sensor slightly away from the trunk of the tree. This avoids direct contact with the tree and allows tree sap to flow down the tree behind the sensor. The spacer also helps to keep the sensor away from the moisture in the tree.

  Furthermore, the spacer allows the sensor to hang vertically rather than laying directly against the bark of the tree which could tilt it at an angle. Also, hanging the sensor vertically improves the radio range of the device.

Preparation checklist

• Work in teams of at least two people.

• Ensure you have downloaded and installed the Silvanet Deployment app and have access to your account.

• Ensure you have a Packet assigned to you.

• Prepare a plan to deploy the sensors in the forest. Prepare your walk through the forest beforehand to install the sensors in the most efficient manner.

• Have sufficient sensors, treenails, spacers (and crop wire, if required) for the day's installation plans.

• Use a waterproof box to hold the sensors and accessories.

• As well as a 3 meter ladder, bring shears or snips for cutting branches and crop wire (if required).

• Bring several rolls of reflective bands, tape or some other method for identifying trees with installed sensors.

Entering the Sensor ID in Deployment app

Before installing the sensor on a tree, you first need to add the Sensor ID in the Deployment app. This links the sensor to the Silvanet Cloud. Data from the sensor can then be transmitted through the Silvanet network to the Silvanet Cloud. The Sensor ID is provided on the back of every sensor. This can be done by scanning the QR Code or entering it manually.

Using the QR Code

To enter the Sensor ID using the QR Code:

1. Login to the Dryad Deployment app using your account credentials.

2. Select the Packet assigned to you. A Packet showing Pending indicates the Packet has not been deployed.

   

   Packet assigned to you

3. Open the Packet. The Packet overview page appears showing a list of sensors to be deployed.

   

   List of sensors to be deployed

4. Select the Map button to view the deployment plan. You can zoom into one of the sensor icons to find the planned location of a sensor. Your current location appears on the map as a blue icon. The following shows two rows of successfully installed sensors (on the left) and two rows of sensors to be installed (on the right).

   

   Map view of planned deployment location

   Note

   Grey icons indicate a sensor inactive. In this case, it has not been installed and is not yet synced with the Silvanet Cloud. For more details of icon colors, see Sensor status icons in Verifying deployment status.

5. Find the planned GPS location (a tree) using the Map view. A 20m overlay appears around your location icon. Select an appropriate tree within this circle on which to install the sensor.

   

   Deployment location

6. Select Install to open the QR Code scanner to link the actual GPS coordinates with the Sensor ID. The Sensor ID is provided as a QR Code and in text form on the back of the sensor.

   

   Scan QR Code

7. Using the QR code scanner, focus on the QR code on the back of the sensor, then select Show me QR code to link the sensor to the actual location.

   The Deployment app automatically fills in the sensor's Latitude and Longitude using the Smartphone's GPS location.

8. You can add additional information in the Notes field such as observations about the location of the sensor (such as located on a hillside, within shadow of a cliff, and so on).

9. Select the Camera icon to take a photo of the Sensor ID.

   

   Installation completed

10. Select Save to complete the installation.

    The sensor icon changes to a yellow color to indicate it was successfully installed and is sending data to the Silvanet Cloud.

    

    Successfully installed

The Deployment app redirects to the Packet overview. The sensor can now be attached to the tree.

Manually adding the Sensor ID

If scanning the QR Code cannot be done for any reason, you can manually add the Sensor ID to the Serial Number field.

To manually enter the Sensor ID:

1. On the Scan QR Code page, select Enter manually.

   

   Enter manually Sensor ID

2. Read the Sensor ID on the back of the sensor and enter it manually in the Serial Number field.

   

   Install page

   To easily copy the Sensor ID you can use a scan text app such as Google Lens. Copy the Sensor ID, then paste the ID in the Serial Number field.

   

   Scan Sensor ID

3. You can add in the Notes field important observations about the location of the sensor (such as located on a hillside, within shadow of a cliff, and so on).

4. Select the Camera icon to take a photo of the Sensor ID.

   

   Installation completed

5. Select Save to complete the installation.

   The sensor icon changes to a yellow color to indicate it was successfully installed and is sending data to the Silvanet Cloud.

   

   Successfully installed

6. The Deployment app redirects to the Packet overview.

7. The sensor can now be attached to the tree.

Deploying on a tree

The sensors are designed with a loop which can be used to attach the device to a tree with a treenail (or crop wire if attached temporarily).

Deploying using treenails

Treenails are pegs which you hammer through a loop in the Sensor into pre-drilled holes in the tree. As they are made of wood rather than metal, they are harmless to the tree. And as they expand due to the tree's moisture, they end up securely deploying the sensor to the tree for a very long time. This is the recommended method as each sensor requires only a single treenail to securely deploy it to a tree.

To deploy a sensor to a tree using treenails:

1. With the help of an assistant, stabilize the ladder against the tree.

2. Locate the correct height (3 m) and direction (facing sun at 12:00 noon) for installing the sensor.

3. Carefully remove a small portion of the bark with an axe. Try not to excessively damage the tree.

   

   Remove small area of bark at the install location

4. Carefully drill a hole approximately 6-7cm into the tree using the 10mm drill bit.

   

   Carefully drill 10mm hole

   Tip

   When drilling into a hardwood tree, start with a smaller drill bit then drill with the 10mm drill bit. Ensure you are using a drill bit for wood.

5. Insert a treenail through the sensor's loop, slip a spacer onto the treenail, then carefully hammer the treenail into the hole drilled into the tree.

   

   Hammer in treenail

6. Ensure the sensor is securely deployed to the tree and hanging loosely and vertically.

   

   Sensor installed with treenail and spacer

7. Mark the tree with the sensor using a reflective band or some other identifying marker.

   

   Tree with Sensor indicated by a marker

8. Continue deploying the remainder of the sensors in the Packet using the same procedure.

Deploying using crop wire (temporary only)

Sensors can be attached using crop wire for short term installations. Crop wire is typically used in agricultural settings such as greenhouses. This solution should only be used for a limited time as the wire will eventually interfere with growth in the tree's girth.

To deploy a sensor using crop wire:

1. Locate the correct height (3 m) and direction (facing sun at 12:00 noon) for installing the sensor.

2. Using a helper, stabilize the ladder against the tree.

3. Cut a length of crop wire at least 50% longer than the circumference of the tree.

4. Insert crop wire through the spacer and sensor as shown below.

   

   Insert crop wire through sensor and spacer

5. Tighten the crop wire around the tree. Ensure it is securely attached and that the sensor cannot slip or move.

   

   Sensor installed with crop wire

6. Continue deploying the remainder of the sensors in the Packet using the same procedure.

14 day calibration period

Once deployed, the Silvanet sensor needs to perform a calibration to determine a value for normal air in the environment around the sensor. This is critical for allowing the sensor to detect a smoldering fire. The calibration period is approximately 14 days after deployment and during this period the sensor does not detect smoldering fires.

Post-calibration period warnings

Once sensors have been deployed and settled, do not interact with the sensors.

Interacting with sensors includes:

• Touching the sensors in any way

• Moving the sensors in any way

• Being in proximity to the sensors

• Having vehicles nearby the test setup

• Bringing any source that could trigger the Phase 1 alert nearby the sensors, including cigarettes, machinery, breathing on the sensor and so on

Sensors are very sensitive to any changes in the environment, including something as simple as touching them or moving them. Any interaction with a sensor triggers a Phase 1 alert, which in turn triggers a Phase 2 process which causes the sensor to perform a set of gas scans to determine if it has detected a fire.

For the sensor to return to normal values so that a valid test can be performed, the sensor needs at least 1 hour to stabilize and return to its base readings. Consequently, the sensor does not measure any changes in the environment if a test is run during this stabilization period.

The 1 hour stabilization period required after touching or moving sensors can cause an interference with the test which results in faulty test results. So, we strongly advise to leave the sensors alone once they are deployed.

Updating firmware

Dryad engineering checks firmware versions of the sensors and if updates are needed, 3 days are usually required for this. Updating is done using FUOTA to send data to all devices simultaneously.

Factors affecting the speed of the updates include:

• Strength of device communication (good vs poor communication)

• Supercapacitor energy storage levels (high vs low energy storage).