Bridge Monitoring in the Internet of Things

M.Eng. Philipp Engel
Hochschule Neubrandenburg – University of Applied Sciences
Faculty of Landscape Sciences and Geomatics

8th GeoIT Wherecamp Conference 2018
24 October 2018, TU Berlin

Monitoring of Buildings and Terrain

• research project at the Neubrandenburg University of Applied Sciences
• development of a geodetic monitoring platform
• monitoring software OpenADMS Node and cloud service OpenADMS Server
• funded by the German Federal Ministry of Education and Research
• managed by Prof. Dr.-Ing. Karl Foppe

• Open Automatic Deformation Monitoring System
• geodetic and geotechnical control measurements in the Internet of Things
• open interfaces for remote control and sensor data exchange
• written in Python 3.6 (~ 4400 lines of code)
• free and open-source (BSD-2-Clause)

Features

• platform-independent
• JSON + MQTT for M2M communication
• NoSQL document stores for persistance
• modularised design
• runs on embedded and single-board computers
• additional sensors without programming

Single-Board Computers

JavaScript Object Notation (JSON)

• simple data exchange format
• persistance with document-oriented NoSQL databases
• used for observation data and sensor configuration
• validation with JSON Schema

JSON Observation Data

{
    "type": "observation",
    "name": "getValues",
    "description": "gets sensor values (temperature, pressure)",
    "id": "21bcf8c16a664b17bbc9cd4221fd8541",
    "node" "6426bf58c20840768912f116740c4974",
    "project" "4a2e8b9d87d849e38bb6911b9f2364ea",
    "target": "tp1",
    "enabled": true,
    "onetime": false,
    "receivers": ["com1", "preProcessor", "distanceCorrector", "fileExporter"],
    "nextReceiver": 4,
    "requestsOrder": ["getTemperature", "getPressure"],
    "requestSets": { … },
    "responseSets": { … },
    "sleepTime": 20.0
}
                    

MQTT

• message-oriented middleware
• lightweight publish/subscribe messaging protocol
• clients subscribe and publish to topics on server
• low overhead
• libraries for many programming languages
• several open-source server implementations

MQTT + JSON

Bridge Monitoring Project

• 24/7 deformation monitoring with OpenADMS since 2016
• two motorway bridges in Lower-Saxony
• built in 1963/1964
• sensors:
• Leica TS16 robotic totalstation
• Reinhardt DFT 485 weather station
• Pt100 resistance temperature detectors
• Raspberry Pi 2 single-board computer with FreeBSD
• mobile data connection, OpenVPN

Conclusions

• stable and reliable monitoring platform
• low hardware costs
• easy to deploy
• visual configuration editor still missing
• cloud computing is work in progress