The design vision is to monitor both air quality and noise effects in a 1-hectare land. Two custom PCB designs will be made, one for sensor data acquisition and one for sensor data processing and display.
The sensor board would acquire various types of data, namely; smog & dust level, temperature, humidity, Carbon dioxide, Monoxide & Oxygen levels, particulate matters as well as Hydrogen and Hydrogen Sulfide levels. Moreover, a microphone will be integrated on the PCB to measure the present sound levels from a 20Hz-20KHz frequency since these are the audible frequency ranges.
To ensure a sensible data acquisition over the whole land lot the inspiration of the sensor locations would come from the meshed network topology. Thus a total of four sensor acquisition PCBs will be placed in each corner of the land and the processing PCB will be placed at the centre of the land. The idea here is that between each corner of the land a variation of the sensor signal is bound to happen, as such by using four sensor boards as far as possible from each other we can get an average of each sensor signal. Each sensor board would transmit the data to the processing boards wirelessly using LoRAWAN for communication.
The premise of mutually separating the sensor boards from the processing boards come with two main advantages, namely, we reduce the total battery drain across all sensors and leave the power-hungry processing centralized, thus reducing costs by using a single DSP and ensuring the longevity of battery life for the whole year.
The processing board is the main link between the user and the data. To ensure that we have constant access to the data regardless of where we are geographically, the processed data is exported in CSV format to a web server via an LTE module. A Wi-Fi module would be designed on the processing boards in case we have access to Wi-Fi at the time and further reduce cost. The back-end work on the server would make it more presentable to the front-end user. As such one would view the data by logging into a website and view the data in real-time.
All the modules (sensor and processing boards) would be enclosed in an IP67 rated enclosure, this would ensure durability against harsh and varying weather conditions. The RF signals are transmitted using a quarter-wavelength antenna and given the availability of cell-towers in such dense places, the use of a meander antenna at the sub GHz level would be suitable. Each module would be placed at an elevated platform such as a light pole or a building’s roof (with permission).
Each board will be powered with a 7Ah lead-acid battery. Each module comes with a compact solar panel that is used to recharge the battery whenever possible. The choice of the battery comes with its fairly lightweight and huge capacity as well as simplicity and reliability.
The real innovation would come into integrating so many sensors into a single PCB and processing all the data on a completely different PCB wirelessly. The global impact of this is achieving what everyone is striving to do with any network, namely, simplicity and versatility. It would be very easy to simply drop a sensor unit anywhere or remove an existing unit without having to alter any other system. The processing board would simply be updated to accept another source of data.
The design is manufacturable with today’s standard, a 4-layer FR-4 PCB will be used throughout the system for economic manufacturing.
In conclusion, the design idea described above is very plausible, simple, reliable, manufacturable and offers a level of innovation that has sparsely been developed. The impact is huge since people can have access to vital data within their environment and can be used to judge the quality of life which can be translated to various markets such as real estate, school zones and the such. Moreover, it opens a real and tangible source for environmentalists and regulators to pinpoint the exact problem being faced within a region using data that is readily available. This, in turn, reduces the time and cost associated with plenty of people within the monitoring and regulation fields.