1 DYNamic Acoustic MAPping DYNAMAP Hardware specifications update (Bluewave) J. Claudi Socoró Carrié (La Salle-Universitat Ramon Llull)
2 INTRODUCTION Aims: The project aims at developing a dynamic noise mapping system able to detect and represent in real time the acoustic impact due to road infrastructures. Project budget: 2.2 M Duration: 2014-2019
3 INTRODUCTION Autonomous National Agency for Roads Milan municipality Mobility Environment Agency for Territory Bicocca University Milan BlueWave Acoustics Accon Environmental Consultants La Salle University - Barcellona IT IT IT IT IT DE ES
4 INTRODUCTION The main goal of the DYNAMAP project is to minimize mapping costs by mean of an automated system based on a capillar noise monitoring sensor network The automation
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6 INTRODUCTION Site #1: Milano municipality Site #2: Rome road ring
7 Bluewave is the company who has in charge to develope the monitoring stations that will measure acoustic data and send sound levels in real time to a central database by mean of a standard telecommunication system (2G, 3G, 4G or Wi-Fi). INTRODUCTION
8 INTRODUCTION A similar system has already been developed by Bluewave and it was installed in Barcelona at the beginning of 2015 by the Department for Noise Reduction of Barcelona. Actually 10 Bluewave sensors are connected to the Sentilo.io platform
9 INTRODUCTION Another similar sytem developed by Bluewave is the Noisemote that can be connected to wifi urban networks and telephonic networks. It can use very small solar panels in order to be totally autonomous and cable-free. Noisemote uses HTTP or HTTPS transfer protocols and Json or other customized formats for data transmission. The sensorized smart object www.noisemote.com
10 The acoustic data must be processed in order to be classified. Infact DYNAMAP is aimed at mapping the road noise, thus any non street related acoustic event must be excluded. The classification
11 It has been decided that, for each sensor, a classified output like this must be produced every second: 151022182000 58.4 0 T first number is a timestamp, the second is a db(a) level and the third number is a flag standing for road or non road event.
12 This task of anomalous event detection (ANED) could be computationally quite expensive to be carried on a central server. Bluewave and LaSalle decided to implement the signal processing and the data classification needed to recognize the road/non-road events on each single sensor node. Thanks to this solution scalability problems can be avoided, distributing the computational load over multiple units The distributed computing
13 THE HARDWARE For the DYNAMAP purpose, a quite powerful hardware system is needed to accomplish the task of events classification. So it was decided to use ARM imx6 multi core based embedded PC with 2GB ram, internal audio board at 44100 Khz and 16bit. For data transmission a standard GPRS/3G modem is used. Minimal version of Linux operating system will be used to run processing scripts Consumer microphone with floor noise below 35 db(a) 6 mm external diameter
14 RELIABILITY Bluewave noise sensors are running since 2011 in the Senseable Pisa project (www.senseable.it) The Senseable Pisa project is carried out by the Dustlab association in order to experiment smart technologies to promote citizen partecipation, crowdsourcing of noise data and big data management.
15 RELIABILITY The stability of frequency response of the microphone over long time has been tested. This test was done unmounting a microphone that has been exposed to atmospheric events for more than three years and comparing it with another never used.
16 RELIABILITY Livello pressione [db(a)] 70 60 50 40 Microfono riferimento Microfono dopo 3 anni e 6 mesi Frequency response of a loudspeaker with sine sweep was measured with the aged microphone and compared with the one measured by a new microphone. Differences of less than 0.5 db are exibithed over all the spectrum. 30 100 1000 10000 Frequenza [Hz]
17 RELIABILITY Time series of measured sound levels with a low cost microphone compared to class I sound level meter.
18 75 RELIABILITY 70 Livello Noisemote [db(a)] 65 60 55 50 45 40 35 35 40 45 50 55 60 65 70 75 Livello strumento classe I [db(a)]
19 RELIABILITY Other microphone ageing tests are still in progress. The ANAS salt spray chamber is used to simulate corrosion in extreme conditions (high temperature, high humidity, high saline concentration)
20 RELIABILITY Detailed tests of microphones thermal response are are now being executed using ANAS thermal chamber in order to evaluate the temperature dependance in the range from -10C to +50C as required for class I instrumentation.
21 FIRST SENSOR A Bluewave prototipe sensor has been installed by ANAS in the six lanes Rome ring road in october 2015. One second time base noise data are collected and sent by mean of HTTP transfer protocol and 3G modem by mean of a REST system.
22 CONCLUSIONS AND FUTURE DEVELOPMENTS The DYNAMAP project foresees the installation of 25 noise sensors in ANAS Rome ring road and 25 noise sensors in Milano Municipality According to the Life+ project scheduling, those sensors will be developed and delivered by Bluewave before July 2016 A noise sensor prototipe has been developed and installed in Rome ring road In order to guarantee a true low cost automatic noise mapping minimization of mantainance cost is needed. To minimize mantainance cost of the noise monitoring network a lot of reliability tests and optimizations are in progress, giving till now good results.
23 Thanks for your attention nencini@blue-wave.com