Sensor Enclosures: Example Application and Implications for Data Coherence

Abstract

Sensors deployed in natural environments, such as rivers, beaches and glaciers, experience large forces and damaging environmental conditions. Sensors need to be robust, securely operate for extended time periods and be readily relocated and serviced. The sensors must be housed in materials that mimic natural conditions of size, density, shape and roughness. We have developed an encasement system for sensors required to measure large forces experienced by mobile river sediment grains. Sensors are housed within two discrete cases that are rigidly conjoined. The inner case exactly fits the sensor, radio components and power source. This case can be mounted within outer cases of any larger size and can be precisely moulded to match the shapes of natural sediment. Total grain mass can be controlled by packing the outer case with dense material. Case design uses Solid-Works TM software, and shape-matching involved 3D laser scanning of natural pebbles. The cases were printed using a HP Designjet TM 3D printer that generates high precision parts that lock rigidly in place. The casings are watertight and robust. Laboratory testing produces accurate results over a wider range of accelerations than previously reported.

Effects of transport and insertion of radio frequency identification (RFID) transponders on resistance and shape of natural and synthetic pebbles: applications for riverine and coastal bedload tracking

“…To meet these criteria, synthetic pebble properties need to be rigorously tested and compared with those of natural pebbles. Several authors created synthetic particles from mixtures of concrete or/and plastic (Maniatis et al, 2013), sometimes with barytes, fiberglass or resin (Sear et al, 2008), or with lead balls and resin (Liedermann et al, 2013). Some of these particles have been equipped with magnetic cores (Schmidt and Gintz, 1995), radio transmitters (Kloesch et al, 2008;Liedermann et al, 2013), 32 mm or 23 mm long PIT tags (Nichols, 2004;Olinde et al, 2012), or 30 mm RFID discs and accelerometers (Olinde et al, 2012).…”

Geomorphological control on boulder transport and coastal erosion before, during and after an extreme extra‐tropical cyclone

“…In the absence of real-time instrumentation of platform wave dynamics (which were not possible to deploy during the storm) and individual boulders (emerging technologies such as smart pebble sensors are still not yet available for this application, e.g. Maniatis et al, 2013), this was the highest temporal resolution and level of quantification that was possible to collect. Ten pairs of boulders that had near identical weights but different pre-transport geomorphological settings illustrate geomorphological control (Table IV).…”

Inertial drag and lift forces for coarse grains on rough alluvial beds

“…We define the body frame b as the coordinate frame of the moving IMU. For an ideal IMU the origin of this frame is located exactly at the center of both the accelerometer and the gyroscope and this center falls precisely on the center of mass of the complete sensor assembly (Maniatis et al, 2013(Maniatis et al, , 2017.…”

“…A particular advance in monitoring technology has been the development of sediment grain scale inertial sensors which provide high frequency data on accelerations and angular velocities experienced by grains during entrainment and motion (Kularatna et al, 2006;Akeila et al, 2010;Frank et al, 2015;Maniatis et al, 2013;Gronz et al, 2016;Maniatis et al, 2017).…”