Optical Displacement Sensor Node

The Optical Displacement Sensor measures changes in distance between the sensor and a target surface. 

Changes in this distance can indicate movement or deformation of the monitored structure. Depending on the installation, the ODS can be used to measure: 

• Tunnel convergence and divergence 

• Structural settlement and heave 

• Bridge and structural movement 

• Rail track slew (buckle) and lateral movement 

• Earthworks and embankment movement 

• Water level changes and dewatering 

• Movement of temporary works and other structures 

The sensor can be configured to monitor different movement directions depending on the position of the sensor and target. 

The ODS uses a visible red laser to measure the distance between the sensor and a target surface. Changes in this distance can indicate movement or deformation of the monitored structure. 

The ODS can also be supplied with an optional integrated triaxial tilt sensor, providing tilt measurements alongside optical displacement data. 

Both configurations communicate wirelessly through a Senceive monitoring network, allowing data to be collected remotely and visualised through WebMonitor™. 

The ODS combines high-precision optical displacement measurement with wireless communications in a compact, robust sensor node. 

An optional integrated triaxial tilt sensor can also be included where additional information about the orientation and movement of the sensor is required. 

Key features include: 

• Optical resolution of 0.1 mm 

• Repeatability of ±0.15 mm 

• Optional triaxial tilt sensing with 0.0001° resolution 

• Long battery life for continuous monitoring 

• Integrated temperature measurement 

• Wireless communication through FlatMesh™ or GeoWAN™ 

• Magnet-triggered aiming mode for easier alignment 

• Robust, weather-resistant enclosure 

• Versatile mounting options 

This makes the ODS suitable for a wide range of structural and geotechnical monitoring applications. 

The ODS is particularly suited to applications where precise, continuous measurement of relative movement is required. 

Typical applications include: 

• Tunnel monitoring – measuring convergence and divergence of tunnel walls or intrados 

• Bridge monitoring – measuring movement of bridge abutments and structural elements 

• Rail track monitoring – measuring lateral track movement or slew (buckle) 

• Building and structural monitoring – detecting settlement, heave and deformation 

• Earthworks and embankments – monitoring movement of slopes and structures 

• Temporary works – monitoring movement of props and other temporary structures 

• Water level monitoring – measuring changes in water level during dewatering or other works 

The optional integrated tilt sensor can provide additional information for applications where the movement or stability of the sensor mounting structure also needs to be monitored.

The measurement range depends on the target surface: 

• 0.05–50 m for natural surfaces 

• 0.05–100 m for white targets 

• 40–150 m for reflecting targets 

The optical sensor has a resolution of 0.1 mm and repeatability of ±0.15 mm. Actual performance depends on the target and environmental conditions. 

The optical sensor has a resolution of 0.1 mm and repeatability of ±0.15 mm. 

Where the ODS is supplied with the optional integrated triaxial tilt sensor, the tilt measurement has a resolution of 0.0001° (0.00175 mm/m) and repeatability of ±0.0005° (±0.0087 mm/m). 

The optional integrated triaxial tilt sensor provides an additional measurement alongside optical displacement, helping users understand movement at the sensor location. 

This can be particularly useful where the stability or movement of the structure supporting the ODS is also important to the monitoring application. 

The optional tilt sensor provides: 

• 0.0001° (0.00175 mm/m) resolution 

• Triaxial measurement 

• Continuous tilt monitoring alongside displacement 

• Additional data to help interpret structural movement 

For applications where tilt data is not required, the ODS can be used as a standalone optical displacement sensor. 

Yes. ODS nodes are well suited to monitoring tunnel convergence and divergence. Multiple sensors can be installed around the tunnel profile to measure changes in distance between opposing points. This allows changes in the tunnel's geometry to be monitored continuously. 

The ODS can provide precise displacement data without the need for wired connections, making it suitable for long-term monitoring in tunnels and other difficult-to-access environments. 

Yes. The ODS can be used to measure lateral movement such as rail track slew (buckle). It can also be used alongside other sensors to provide a broader picture of changes in track geometry and asset behaviour. Where required, the optional integrated triaxial tilt sensor can provide additional information about movement at the sensor location.

The ODS has versatile mounting options to suit different structures and applications. 

Available mounting solutions include: 

• Magnetic mounting 

• Screw-fixed mounting 

• Trackbed mounting 

• Stake and pole mounting 

• Adjustable mounting plates and brackets 

• Solutions for vertical and inclined surfaces 

A range of mounting accessories is available to help position and align the sensor with its target.

The ODS includes a magnet-triggered aiming mode to make alignment with the target easier during installation. This helps installers accurately position the optical sensor, making deployment and commissioning quicker and more straightforward.

The ODS is designed for demanding monitoring environments and is waterproof to IP66/IP67/IP68. The sensor features a robust die-cast aluminium housing and weather-resistant protection suitable for outdoor and underground applications. The operating temperature range for full functionality is -10°C to +50°C.

The ODS has an integrated long-life battery designed for long-term monitoring without regular site visits. 

Typical battery life is up to 10 years, depending on the communications configuration, reporting interval, target characteristics and environmental conditions. 

Yes. The ODS includes an integrated temperature sensor, providing additional temperature readings alongside displacement measurements. 

Where the optional triaxial tilt sensor is included, tilt data is also available from the same sensor node. 

Temperature data can help users understand environmental influences on monitored structures and support analysis of movement trends. 

Yes. The ODS is a wireless sensor node that transmits measurement data through Senceive's wireless communications platforms. 

It is available for FlatMesh™ and GeoWAN™ networks, allowing the appropriate communications architecture to be selected for the monitoring application. 

FlatMesh uses a mesh network architecture, while GeoWAN provides long-range wireless communications for applications where sensors may be distributed over large areas. 

Data from the ODS is transmitted wirelessly to a Gateway and can then be visualised through WebMonitor™ or other third party data visualisation platforms. 

Users can analyse trends and configure alerts according to the requirements of the monitoring project. 

Yes. ODS sensor nodes can be combined with other sensors within the same monitoring system. 

For example, Optical Displacement Sensors can be used alongside: 

• Triaxial tilt sensors 

• Temperature sensors 

• Crack sensors 

• Piezometers 

• In-place inclinometers 

• Strain gauges 

• Other third party geotechnical and structural instruments 

This allows multiple parameters to be monitored through a single wireless monitoring system, providing a more complete picture of asset behaviour. 

*Battery life depends on reporting interval, target characteristics and environmental conditions.