Distributed network of smartphone sensors: a new tool for scientific field measurements

TL;DR

This paper introduces a methodology for using a network of smartphones as distributed, synchronized mechanical sensors for field measurements, demonstrating high accuracy and reliability in outdoor conditions.

Contribution

It presents a novel approach to utilize smartphones as autonomous, time-synchronized sensors for scientific measurements, including a synchronization protocol and validation tests.

Findings

Achieved smartphone clock synchronization accuracy of 60 microseconds.

Validated the reliability of smartphone fleets in measuring mechanical waves outdoors.

Developed an Android app and server system for remote, synchronized data collection.

Abstract

Smartphones sensors are now commonly used by a worldwide audience thanks to their availability, high connectivity, and versatility. Here, we present a methodology to use a collection of smartphones, namely a fleet, as a distributed network of time-synchronized mechanical sensors. We first present the mechanical tests we develop to evaluate the smartphone sensor accuracy. We then describe how to use efficiently a distributed network of smartphones as autonomous sensors. We use a combination of an Android application hosted on each phone (Gobannos), and a server application (Phonefleet) on a controlling host to perform the tasks in parallel remotely. We implement in particular a time synchronization protocol based on UDP communication. We achieved an accuracy of the smartphone clock synchronisation of 60 microseconds. Using two test cases in realistic outdoor conditions, we eventually prove the reliability of a smartphone fleet to measure mechanical wave measurements in field conditions.