How to deploy sensors

Sensors are deployed in locations as set in the Site Packet, then calibrated for 14 days before ready to detect fires.

Deployment overview

• Locate a healthy tree nearest to the GPS coordinates set for the sensor in the Silvanet Deployment app.

• Register the Device ID of the sensor.

• Deploy (attach) the sensor to the tree according to sensor deployment guidelines.

Attach sensors to trees

Sensors can be attached to trees using treenails for permanent attachment or using crop wire for temporary attachment.

Using treenails (Long term)

Treenails are wooden pegs used to securely attach sensors to a tree. As they are made from wood, they do not affect the health of the tree. Over time the tree's moisture causes the treenails to expand securely attaching the sensor to the tree.

A 10 mm hole is drilled into the tree 3 m from the forest floor on the side of the tree where sunlight would strike the tree at 12:00 noon. The treenails are fed through a loop in the sensor and a spacer and then hammered into the tree.

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).

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

   

   Remove small area of bark at the install location

4. Carefully drill a hole approximately 6-7 cm into the tree using the 10mm drill bit. Do not drill deeper than this recommended depth to prevent unnecessary damage to the tree.

   Note

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

   

   Carefully drill 10mm hole

5. Insert a treenail through the sensor's loop, slip a spacer onto the treenail and then carefully hammer the treenail into the hole. Ensure the treenail is not damaged by the hammering.

   

   Hammer in treenail through sensor and spacer

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

   

   Sensor attached with treenail and spacer

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

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.

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).

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 14 day calibration period 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.(1)

1. A smoldering fire is defined to be a slow, flameless combustion of a biomass material such as forest floor material, branches, leaves, and so on.

The calibration period is approximately 14 days after deployment and during this period the sensor does not detect smoldering fires. It may also send false Fire Alerts during this period, up to possibly even a month after deployment.

Warnings

Sensors are very sensitive to any changes in the environment. Any interaction with a sensor triggers a Phase 1 alert. This may trigger a Phase 2 process which causes the sensor to perform a set of gas scans to determine if it has detected a fire.

Don't interact with sensors

Once a sensor has been calibrated, interacting with sensors can include:

• Touching the sensors, such as adjusting the angle of the sensor

• Moving the sensors to another tree or redeploying the sensor on the tree

• Being in proximity to the sensors such as breathing on the sensor

• Running vehicles near the deployed sensors

• Bringing any source of VOCs near the sensor that could trigger the Phase 1 alert such as cigarettes or machinery

2-4 hrs needed to return to normal values

If interactions with a sensor have triggered a Phase 1, the sensor needs at least 2 to 4 hours to return to normal values.

During this period, the sensor does not measure any changes in the environment. After this period, the sensor returns to a ready state.

Firmware updates (FUOTA)

When the current firmware in a sensor requires updating, FUOTA is used to send simultaneously the latest firmware update to a predetermined number of sensors in a Site.

Dryad engineering checks the current firmware versions of the sensors and if an update is required then three days are usually needed to send the updates to the sensors. This is because updates are sent in data packets of a restricted size and then are reconstituted in the sensor before an update is done.

Dryad engineering notifies the customer before performing any firmware updates to a Silvanet deployment.

Factors affecting the length of time for FUOTA include:

• Strength of device communication (good vs poor communication)

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