Structural Health Monitoring of Civil Infrastructures Using Wireless Vibration Sensors

The deterioration of the old building and civil Infrastructure can lead to fatal and Hazardous situation. The constant monitoring of these structures is mandatory. Structural health monitoring is an extremely important methodology in evaluating the ‘health’ of a structure by assessing the level of deterioration and the remaining service life of civil infrastructure systems.

Wireless Sensor Networks has been installed in many industrial applications like vibration analysis of wind turbines , vibration analysis of hydro turbines etc. and has done remarkably well in irradicating many of the industrial complications. Measuring the number of vibrations, temperature and other aspects can help us to prevent the damage and deterioration of the infrastructure.

In this Instructable we will be going through Wireless Vibration and Temperature Sensors and it's advantages in monitoring structural Health. So here we will be demonstrating the following-

• Wireless Vibration and Temperature Sensors .
• Structural monitoring using these Sensors.
• Gathering and analysing the data using Wireless gateway device
• Publishing and Subscribing to Sensor data using Ubidots

Software Specification

• An UbiDots account
• Arduino IDE

Hardware Specification

• ESP32
• Wireless Temperature and Vibration Sensor
• Zigmo Gateway receiver

This is a Long Range Industrial IoT wireless vibration and temperature sensor , boasting up to a 2 Mile range using a wireless mesh networking architecture. Incorporating a 16-bit Vibration and Temperature sensor, this sensor transmits highly accurate vibration data at user-defined intervals. It has the following features :

• Industrial Grade 3-axis Vibration Sensor with ±32g Range
• Calculates RMS, MAX, and MIN g Vibration
• Noise Removal using Low-pass Filter
• Frequency Range (Bandwidth) up to 12,800 Hz
• Sample Rate up to 25,600Hz
• Encrypted Communication with 2 Mile Wireless Range
• Operating Temperature Range -40 to +85 °C
• Wall-Mounted or Magnet Mounted IP65 Rated EnclosureExample Software for Visual Studio and LabVIEW
• Vibration Sensor with External Probe Option
• Up to 500,000 Transmissions from 4 AA BatteriesMany Gateway and Modem Options Available

Here are some recommended Vibration standards, you can compare these readings with our Long Range IoT Wireless Vibration Temperature Sensor to determine if your device is operating properly or if it may require service (note that actual equipment and application may vary):

• 0.01g or Less — Excellent condition, No action required
• 0.35g or less — Good Condition, No action required unless the machine is noisy or running at an abnormal temperature
• 0.5g or less — Fair Condition, No action required unless the machine is noisy or running at an abnormal temperature
• 0.75g or More— Rough Condition, possible action required if the machine is noisy and also check the bearing temperature
• 1g or More — Very Rough Conditions, further analysis and see if it's doing this continuously. Also, check for noise and temperature
• 1.5g or More — Danger Level, there is definitely a problem in the machine or installation. Also, check the temperature Log
• 2.5g or More — Shut-down the Machine immediately and look for possible causes. Call a technician for immediate repair For Heavy Machinery these readings could be 1.5 times to 2 times more than listed above.

The vibration values, that we are getting from the sensors are in millis. These consists of the following values

• rms vibration along the x-axis.
• rms vibration along the y-axis.
• rms vibration along the z-axis.
• minimum vibration along the x-axis.
• minimum vibration along the y-axis.
• minimum vibration along the z-axis.
• maximum vibration along the x-axis.
• maximum vibration along the y-axis.
• maximum vibration along the z-axis.

Now to visualize the published data in Ubidots dashboard. we need to add the variables and the widgets to it

• Click '+' sign on the top right corner

• Select the Widget
• add the variable

Ubidots gives us another tool to send an email notification to the user. We have created an event of temperature alert that is whenever the temperature goes beyond 30 degrees an automated mail will be sent to the user. When it comes back to the normal state another automated mail is sent to the user to notify him/her.

The firmware of this setup can be found in this GitHub repository