Crack Sensor Node


The FlatMesh Crack Sensor Node interfaces to a linear displacement sensor. Its high precision sampling circuit powers the sensor and reports its measurements through Senceive’s FlatMesh wireless communications network to a FlatMesh Gateway. It has been successfully used in many applications, including those measuring:

  • Crack movement
  • Pile separation
  • Structural movement
  • Expansion joint monitoring

Key benefits

  • Waterproof, robust connectors for simple installation
  • Automatic sensor type detection
  • Extremely low noise performance
  • 16-bit resolution (65,536 steps over the full scale)
  • Integrated long life battery
  • 12-15 years’ battery life, including when acting as a relay node within the mesh communications network
  • Integrated temperature sensor
  • One and two channel variants readily available, up to six channels available on request
  • Waterproof to IP66 / IP67 / IP68
  • Firmware is remotely upgradeable over the air via the gateway reducing costly site visits
  • Variety of fixings available for easy installation on site

Physical specifications

Parameter Value
* Approximate values only
Dimensions excluding antenna 90 x 90 x 60 mm

90 x 96 x 60 mm (including vent)

Total Mass 0.5 kg*
Housing Material Die cast aluminium
Protection (BS EN 60529: 1992 + A2: 2013) IP66 / IP67

IP68 at 1m for 24 hours

Includes connectors while unmated

Mounting Options Clearance holes for M4 socket head screw in bottom

M4 blind holes in side

Plates and brackets available for magnetic fixing, track bed, stake and pole mounting, and many other applications

Operating Temperature Range -40°C to +85°C

FlatMesh Radio Specifications

Parameter Value
* Consult with Senceive for your application
Communication Type Proprietary FlatMesh v3 Mesh Networking Protocols

IEEE 802.15.4 compliant

Frequency Band 2400 – 2485 MHz ISM Band
Maximum Transmit Power (EN 300 328 v1.8.1) 6.5dBm
Maximum Permitted Antenna Gain 2.2dBi
Range Up to 300m depending on the environment and fitted antenna *

Crack Sensor Interface

Parameter Value
Circuit Topology Voltage divider
Stimulus 2.5V, 100mA max
Resolution 0.0015% of full scale
Noise Level 0.005% of full scale (typical peak to peak)

Internal battery

Parameter Value
Battery Type Lithium Thionyl Chloride
Nominal Voltage 3.6V
Nominal Capacity 19000mAh
Typical Battery Life 12-15 years at 20/30 minute reporting intervals, including when acting as a relay node


  • Tested to conformity with all the essential requirements of R&TTE Directive 1999/5/EC and RoHS Directive 2011/65/EU
  • Network Rail Acceptance PA05/04146
  • London Underground Approved Product ID 2073

Ordering Information and Accessories

Model Description
FM3N-CS FlatMesh 3 Crack Sensor Node (one port)
FM3N-CS2 FlatMesh 3 Crack Sensor Node (two port)

Potentiometer 25mm crack sensor
IP66 rated, with connector fitted
Use with FF-CS1

FS-CS125 Potentiometer 125mm crack sensor IP66 rated, with connector fitted Use with FF-CS1
FF-CS1 Crack Sensor mounting kit
FF-MP-S360 Swivel mounting kit with 360-degree adjustment range Mounting bracket for node
FF-MP-V Vertical mounting plate
– use U-bolts to fix to poles or stakes
– use glue to fix to walls where drilling is not permitted
Use with FF-MP-S360
FA-FM-WPS Waterproof straight antenna Overall node height 168mm (approx) when fitted Maximum gain +1.1dBi
FA-FM-LPS Waterproof low profile straight antenna
Minimum overall node height, perfect for track bed and tight spots
Overall node height 92mm (approx) when fitted
Maximum gain 0dBi
FA-FM-ADJ Adjustable angle antenna Flexible installation, perfect for use in tunnels and indoor environments Overall node height 202mm (approx) when fitted and upright Overall node height 102mm (approx) when fitted and at 90-degree angle Maximum gain +2dBi
FC-NC Antenna cover kit
Use with FA-FM-LPS antenna
Overall node height 96mm (approx) when fitted