The purpose for this field trial is to collect atmospheric information by mobile sensor system installed on garbage collection cars in Fujisawa City. In Japan, many people are suffering from hay fever caused by microscopic particles of pollen. In addition, annual average concentration of PM2.5 (fine particules) is increasing year by year.
Providing air pollution sensor information measured by sensorized garbage collection cars is helpful for people’s health. For example, since citywide information of atmosphere is available for citizens and visitors in Fujisawa city, they can avoid going out or hanging laundry outside when microscopic particles of pollen spread a lot. In terms of city resource management, location information of garbage collection cars is important for Fujisawa municipality to plan effective routes to collect garbage in the city in order to reduce CO2 emission.
For sensorized garbage collection cars, we designed a custom sensor board and re-designed the entire system from the prototype developed in the 1st year. Figure 1 shows a block diagram of the system and Figure 2 shows a developed custom sensor board.
There is a sensor node for controlling several sensors on a sensor board. We used Common Intermediate Language (CIL)*-based virtual machine developed by NTTRD for implementing the program on the sensor node. We automated the system without requiring extra operations such as powering on a Windows tablet by drivers. For this purpose, a mbed board u-blox C027 is adopted as a gateway for intermediating communication between a sensor node and a server so that the system starts collecting sensor data after the engine is started. The program running on u-blox/linux gathers sensor data collected by the sensor node, pollen counts from the pollen sensor, and GPS data from the receiver, and sends a bunch of data to a remote server via 3G mobile networks every 30 seconds.
*Common Intermediate Language (CIL) is the lowest-level human-readable language defined by the Common Language Infrastructure (CLI) specification and in used by the .NET Framework and Mono (Wikipedia)
The remote server stores the sensor data from each sensorized garbage collection car, and can transmit the thinned-out sensor data to other cloud server via XMPP protocol. The system has the following features:
- 13 kinds of atmospheric sensors: CO, O3, NO2, air contaminants (two types of gases), dust, PM2.5, pollen, luminance, UV, temperature, humidity, and ambient noise.
- The GPS location of a car is measured every second and atmospheric sensor values are measured every one to five seconds depending on the sensor type. A bunch of measured sensor data is sent to a server every 30 seconds via 3G mobile networks.
- Providing the position and operational status of each garbage collection car as well as spatial distribution of each sensor value on a map in real-time.
Fujisawa municipality can monitor the location and operational status of each garbage collection car. As the garbage cars move along citywide routes, they can also provide detailed atmospheric information in wide area of Fujisawa city along with information measured at existing stationary monitoring stations.
A person asks a friend to go out and do an outdoor activity in Fujisawa area. However, he/she has a hay fever caused by microscopic particles of pollen so he/she is having hard time to decide if he/she should go or not. He/she looks up atmospheric information on the website provided by Fujisawa city, which is collected by sensorized garbage collection cars. Since pollen is not spread that much, he/she could go out with friends.
Integration with ClouT platform
Figure 3 shows integration on ClouT architecture for Fujisawa field trial. The system can efficiently use each functional component in CIaaS, CPaaS and CsaaS. In CIaaS layer, Fujisawa city data collector is based on Sensorizer functionality and Data Transporter uses Uniform Access to IoT Data functionality in ClouT reference architecture. The sensor data from garbage collection cars are also managed by Fujisawa city data collector. In CPaaS layer, we can leverage sensor data healing mechanism and secure data storage functionality.
Even though atmospheric information is available on website of Japan Meteorological Agency, the sensors on the garbage collection cars can get local and detailed information specifically in the areas. Citizens and visitors can get atmospheric information such as microscopic particles of pollen and PM2.5 and plan their activities．Especially PM2.5 has a harmful effect on the health. Therefore, for example, schools and preschools can utilize this information and they can judge if their events can be held outside or not.