{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,28]],"date-time":"2026-02-28T04:28:06Z","timestamp":1772252886591,"version":"3.50.1"},"reference-count":51,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2022,4,6]],"date-time":"2022-04-06T00:00:00Z","timestamp":1649203200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000015","name":"United States Department of Energy","doi-asserted-by":"publisher","award":["DE-AC02-05CH11231"],"award-info":[{"award-number":["DE-AC02-05CH11231"]}],"id":[{"id":"10.13039\/100000015","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Landslides are a global and frequent natural hazard, affecting many communities and infrastructure networks. Technological solutions are needed for long-term, large-scale condition monitoring of infrastructure earthworks or natural slopes. However, current instruments for slope stability monitoring are often costly, require a complex installation process and\/or data processing schemes, or have poor resolution. Wireless sensor networks comprising low-power, low-cost sensors have been shown to be a crucial part of landslide early warning systems. Here, we present the development of a novel sensing approach that uses linear arrays of three-axis accelerometers for monitoring changes in sensor inclination, and thus the surrounding soil\u2019s deformation. By combining these deformation measurements with depth-resolved temperature measurements, we can link our data to subsurface thermal\u2013hydrological regimes where relevant. In this research, we present a configuration of cascaded I2C sensors that (i) have ultra-low power consumption and (ii) enable an adjustable probe length. From an electromechanical perspective, we developed a novel board-to-board connection method that enables narrow, semi-flexible sensor arrays and a streamlined assembly process. The low-cost connection method relies on a specific FR4 printed circuit board design that allows board-to-board press fitting without using electromechanical components or solder connections. The sensor assembly is placed in a thin, semi-flexible tube (inner diameter 6.35 mm) that is filled with an epoxy compound. The resulting sensor probe is connected to an AA-battery-powered data logger with wireless connectivity. We characterize the system\u2019s electromechanical properties and investigate the accuracy of deformation measurements. Our experiments, performed with probes up to 1.8 m long, demonstrate long-term connector stability, as well as probe mechanical flexibility. Furthermore, our accuracy analysis indicates that deformation measurements can be performed with a 0.390 mm resolution and a 95% confidence interval of \u00b10.73 mm per meter of probe length. This research shows the suitability of low-cost accelerometer arrays for distributed soil stability monitoring. In comparison with emerging low-cost measurements of surface displacement, our approach provides depth-resolved deformation, which can inform about shallow sliding surfaces.<\/jats:p>","DOI":"10.3390\/s22072814","type":"journal-article","created":{"date-parts":[[2022,4,7]],"date-time":"2022-04-07T21:08:22Z","timestamp":1649365702000},"page":"2814","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Low-Power, Flexible Sensor Arrays with Solderless Board-to-Board Connectors for Monitoring Soil Deformation and Temperature"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2672-2998","authenticated-orcid":false,"given":"Stijn","family":"Wielandt","sequence":"first","affiliation":[{"name":"Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7673-7346","authenticated-orcid":false,"given":"Sebastian","family":"Uhlemann","sequence":"additional","affiliation":[{"name":"Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6269-8676","authenticated-orcid":false,"given":"Sylvain","family":"Fiolleau","sequence":"additional","affiliation":[{"name":"Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9871-5650","authenticated-orcid":false,"given":"Baptiste","family":"Dafflon","sequence":"additional","affiliation":[{"name":"Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA"}]}],"member":"1968","published-online":{"date-parts":[[2022,4,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2161","DOI":"10.5194\/nhess-18-2161-2018","article-title":"Global fatal landslide occurrence from 2004 to 2016","volume":"18","author":"Froude","year":"2018","journal-title":"Nat. Hazards Earth Syst. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2585","DOI":"10.5194\/nhess-20-2585-2020","article-title":"Preface: Landslide\u2013transport network interactions","volume":"20","author":"Taylor","year":"2020","journal-title":"Nat. Hazards Earth Syst. Sci."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2093","DOI":"10.5194\/nhess-18-2093-2018","article-title":"Natural hazard events affecting transportation networks in Switzerland from 2012 to 2016","volume":"18","author":"Voumard","year":"2018","journal-title":"Nat. Hazards Earth Syst. Sci."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"799","DOI":"10.1007\/s11440-014-0324-1","article-title":"Construction, management and maintenance of embankments used for road and rail infrastructure: Implications of weather induced pore water pressures","volume":"9","author":"Glendinning","year":"2014","journal-title":"Acta Geotech."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1144\/qjegh2016-080","article-title":"Current and future role of instrumentation and monitoring in the performance of transport infrastructure slopes","volume":"50","author":"Smethurst","year":"2017","journal-title":"Q. J. Eng. Geol. Hydrogeol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1007\/s10346-013-0436-y","article-title":"The Varnes classification of landslide types, an update","volume":"11","author":"Hungr","year":"2014","journal-title":"Landslides"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"438","DOI":"10.1016\/j.geomorph.2015.10.027","article-title":"Assessment of ground-based monitoring techniques applied to landslide investigations","volume":"253","author":"Uhlemann","year":"2016","journal-title":"Geomorphology"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"457","DOI":"10.1007\/s10346-011-0300-x","article-title":"The deployment of deep-earth sensor probes for landslide detection","volume":"9","author":"Ramesh","year":"2012","journal-title":"Landslides"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"337","DOI":"10.1002\/nsg.12102","article-title":"Four-dimensional electrical resistivity tomography for continuous, near-real-time monitoring of a landslide affecting transport infrastructure in British Columbia, Canada","volume":"18","author":"Holmes","year":"2020","journal-title":"Surf. Geophys."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"012005","DOI":"10.1088\/1755-1315\/26\/1\/012005","article-title":"Research-informed design, management and maintenance of infrastructure slopes: Development of a multi-scalar approach","volume":"26","author":"Glendinning","year":"2015","journal-title":"IOP Conf. Ser. Earth Environ. Sci."},{"key":"ref_11","first-page":"1","article-title":"Applicability of satellite radar imaging to monitor the conditions of levees","volume":"12","author":"Jonkman","year":"2019","journal-title":"J. Flood Risk Manag."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"218","DOI":"10.1016\/j.rse.2016.04.012","article-title":"Monitoring of subsidence with UAVSAR on Sherman Island in California\u2019s Sacramento\u2013San Joaquin Delta","volume":"181","author":"Sharma","year":"2016","journal-title":"Remote Sens. Environ."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Schenato, L. (2017). A Review of Distributed Fibre Optic Sensors for Geo-Hydrological Applications. Appl. Sci., 7.","DOI":"10.3390\/app7090896"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1328","DOI":"10.1038\/s41598-018-36675-8","article-title":"Distributed Acoustic Sensing Using Dark Fiber for Near-Surface Characterization and Broadband Seismic Event Detection","volume":"9","author":"Dou","year":"2019","journal-title":"Sci. Rep."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Thoen, B., Callebaut, G., Leenders, G., and Wielandt, S. (2019). A Deployable LPWAN Platform for Low-Cost and Energy-Constrained IoT Applications. Sensors, 19.","DOI":"10.3390\/s19030585"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1016\/j.adhoc.2012.09.002","article-title":"Design, development, and deployment of a wireless sensor network for detection of landslides","volume":"13","author":"Ramesh","year":"2014","journal-title":"Ad Hoc Netw."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"124","DOI":"10.1016\/j.enggeo.2012.07.017","article-title":"Design and implementation of a landslide early warning system","volume":"147\u2013148","author":"Intrieri","year":"2012","journal-title":"Eng. Geol."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Wielandt, S., and Dafflon, B. (2020, January 1\u20135). A Local LoRa Based Network Protocol with Low Power Redundant Base Stations Enabling Remote Environmental Monitoring. Proceedings of the 2020 54th Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, CA, USA.","DOI":"10.1109\/IEEECONF51394.2020.9443344"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Callebaut, G., Leenders, G., Van Mulders, J., Ottoy, G., De Strycker, L., and Van der Perre, L. (2021). The Art of Designing Remote IoT Devices\u2014Technologies and Strategies for a Long Battery Life. Sensors, 21.","DOI":"10.3390\/s21030913"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"833","DOI":"10.1007\/s10706-012-9569-3","article-title":"Asset Management and Safety Assessment of Levees and Earthen Dams Through Comprehensive Real-Time Field Monitoring","volume":"31","author":"Abdoun","year":"2013","journal-title":"Geotech. Geol. Eng."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Ruzza, G., Guerriero, L., Revellino, P., and Guadagno, F.M. (2020). A Multi-Module Fixed Inclinometer for Continuous Monitoring of Landslides: Design, Development, and Laboratory Testing. Sensors, 20.","DOI":"10.3390\/s20113318"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Wielandt, S., and Dafflon, B. (November, January 31). Minimizing Power Consumption in Networks of Environmental Sensor Arrays using TDD LoRa and Delta Encoding. Proceedings of the 2021 55th Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, CA, USA.","DOI":"10.1109\/IEEECONF53345.2021.9723227"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"2853","DOI":"10.5194\/tc-13-2853-2019","article-title":"A distributed temperature profiling method for assessing spatial variability in ground temperatures in a discontinuous permafrost region of Alaska","volume":"13","author":"Dafflon","year":"2019","journal-title":"Cryosphere"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"154","DOI":"10.1016\/j.jhydrol.2009.10.033","article-title":"Estimation of seepage rates in a losing stream by means of fiber-optic high-resolution vertical temperature profiling","volume":"380","author":"Vogt","year":"2010","journal-title":"J. Hydrol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/j.coldregions.2017.09.002","article-title":"Predicting movement using internal deformation dynamics of a landslide in permafrost","volume":"143","author":"Darrow","year":"2017","journal-title":"Cold Reg. Sci. Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"439","DOI":"10.1002\/wat2.1126","article-title":"Landslide hydrology: From hydrology to pore pressure","volume":"3","author":"Bogaard","year":"2015","journal-title":"Wiley Interdiscip. Rev. Water"},{"key":"ref_27","first-page":"1","article-title":"Feasibility of soil moisture estimation using passive distributed temperature sensing","volume":"46","author":"Rutten","year":"2010","journal-title":"Water Resour. Res."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2089","DOI":"10.5194\/tc-11-2089-2017","article-title":"Coupled land surface\u2013subsurface hydrogeophysical inverse modeling to estimate soil organic carbon content and explore associated hydrological and thermal dynamics in the Arctic tundra","volume":"11","author":"Tran","year":"2017","journal-title":"Cryosphere"},{"key":"ref_29","first-page":"1","article-title":"Estimation of depth-resolved profiles of soil thermal diffusivity from temperature time series and uncertainty quantification","volume":"2021","author":"Brunetti","year":"2021","journal-title":"Earth Surf. Dyn. Discuss."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"120","DOI":"10.1016\/j.coldregions.2008.03.003","article-title":"Estimation of soil thermal properties using in-situ temperature measurements in the active layer and permafrost","volume":"55","author":"Nicolsky","year":"2009","journal-title":"Cold Reg. Sci. Technol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"392","DOI":"10.1002\/ppp.2098","article-title":"Permafrost thaw-related slope failures in Alaska\u2019s Arctic National Parks, c. 1980\u20132019","volume":"32","author":"Swanson","year":"2021","journal-title":"Permafr. Periglac. Process."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"719","DOI":"10.5194\/tc-16-719-2022","article-title":"A distributed temperature profiling system for vertically and laterally dense acquisition of soil and snow temperature","volume":"16","author":"Dafflon","year":"2022","journal-title":"Cryosphere"},{"key":"ref_33","unstructured":"Wielandt, S., and Dafflon, B. (2021). Sensor Probes Including Boards Having Solderless Interconnects. (17\/543,032), U.S. Patent."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"4887","DOI":"10.1109\/JSEN.2020.3029892","article-title":"Dynamic Measurement of Well Inclination Based on UKF and Correlation Extraction","volume":"21","author":"Yang","year":"2021","journal-title":"IEEE Sens. J."},{"key":"ref_35","unstructured":"Fisher, C.J. (2010). Using an Accelerometer for Inclination Sensing, Analog Devices. Application Note AN-1057."},{"key":"ref_36","unstructured":"Murphy, C. (2017). Choosing the Most Suitable MEMS Accelerometer for Your Application\u2013Part 1, Analog Devices. Application Note."},{"key":"ref_37","unstructured":"Analog Devices (2015). 3-Axis, \u00b12 g\/\u00b14 g\/\u00b18 g\/\u00b116 g Digital Accelerometer\u2014ADXL345 Rev. E., Analog Devices. Data Sheet."},{"key":"ref_38","unstructured":"Texas Instruments (2015). SN74LVC1G175 Single D-Type Flip-Flop with Asynchronous Clear, Texas Instruments. Data Sheet."},{"key":"ref_39","unstructured":"Texas Instruments (2021). TMP117 High-Accuracy, Low-Power, Digital Temperature Sensor with SMBus and I2C-Compatible Interface, Texas Instruments. Data Sheet."},{"key":"ref_40","unstructured":"Crell, C. (2018). Product Data Sheet\u2014Energizer L91 Ultimate Lithium (L91GL1218), Energizer. Data Sheet."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1910","DOI":"10.1109\/JIOT.2019.2953804","article-title":"Characterization of LoRa Point-to-Point Path Loss: Measurement Campaigns and Modeling Considering Censored Data","volume":"7","author":"Callebaut","year":"2020","journal-title":"IEEE Internet Things J."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Tong, C. (2022). Advanced Materials for Printed Flexible Electronics, Springer.","DOI":"10.1007\/978-3-030-79804-8"},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Engel, P.A. (1993). Structural Analysis of Printed Circuit Board Systems, Springer.","DOI":"10.1007\/978-1-4612-0915-7"},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Kyeong, S., and Pecht, M.G. (2021). Electrical Connectors: Design, Manufacture, Test, and Selection, John Wiley & Sons.","DOI":"10.1002\/9781119679837"},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Ganesan, S., and Pecht, M.G. (2006). Lead-Free Electronics, John Wiley & Sons.","DOI":"10.1002\/047000780X"},{"key":"ref_46","unstructured":"Japan Solderless Terminal (2021). SH Connector: 1.0 mm Pitch\/Disconnectable Crimp Style Connectors, Japan Solderless Terminal. Data Sheet."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"6761","DOI":"10.1007\/s11665-019-04424-1","article-title":"Study of the Thermomechanical Performance of FR-4 Laminates During the Reflow Process","volume":"28","author":"Hinojosa","year":"2019","journal-title":"J. Mater. Eng. Perform."},{"key":"ref_48","unstructured":"Epoxies Inc. (2012). Unfilled Low Durometer Clear Urethane Elastomers, Epoxies Inc.. Data Sheet."},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Aarts, A., Neves, H.P., Puers, R.P., and van Hoof, C. (2008, January 1\u20134). Interconnect for Out-of-Plane Mems Assembly. Proceedings of the 2008 International Interconnect Technology Conference, Burlingame, CA, USA.","DOI":"10.1109\/IITC.2008.4546946"},{"key":"ref_50","unstructured":"Das, B.M., and Sobhan, K. (2012). Principles of Geotechnical Engineering Eighth Edition, SI, Cengage Learning."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"1147","DOI":"10.1063\/1.555614","article-title":"Electrical resistivity of copper, gold, palladium, and silver","volume":"8","author":"Matula","year":"1979","journal-title":"J. Phys. Chem. Ref. Data"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/7\/2814\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T22:49:17Z","timestamp":1760136557000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/7\/2814"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,4,6]]},"references-count":51,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2022,4]]}},"alternative-id":["s22072814"],"URL":"https:\/\/doi.org\/10.3390\/s22072814","relation":{"has-preprint":[{"id-type":"doi","id":"10.20944\/preprints202203.0244.v1","asserted-by":"object"}]},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,4,6]]}}}