During Proteus first year, the consortium expploited detailed use cases to define technical and business requirements for prototyping. From those evolved a very detailed design, based on which hardware and software development started out. On the hardware side, several versions of sensor chip based on MEMS and CNT sensors were developed to monitor temperature, pressure, flow rate, conductivity, pH, chlorine and chloride. A CMOS chip capable of interfacing these sensor chips was designed and sent for fabrication. On the software side, the cognitive node management software, the data model and the software for prediction of future values were developed and implemented into a demonstrator.
During the second year, the separate hardware building blocks were finalized and validated in the lab. We demonstrated the first successful co-integration, into a single 1cm² silicon chip, of MEMS- and CNT-based chemical and physical sensors (counting a total 16 different sensing elements for redundancy) capable of monitoring the 7 expected parameters. The sensitivity and selectivity of all the sensing elements were evaluated, with most of the sensors featuring linear responses to the target parameter. Moreover, the measured CMOS chip performances were shown to respect design. A piezoelectric vortex generator (PVG) was also successfully developed to harvest energy from drink water pipes (as part of a multi-source energy harvesting strategy).
Following their lab validation, a set of CMOS and sensor chips was integrated into dedicated PCB and housing to produce 13 prototypes, the so-called sensor caps. Each Proteus node, called PNODE, is composed of one sensor cap with its dedicated, battery-fitted electronic board connected to one or more energy harvesters. The electronic board and its software enable data gathering by any water management system via ModBus over RS485 or over LORA.
This work enabled the validation of the full system in Sense-City 40m-long water loop. Results showed proper operation of temperature, pressure, conductivity, pH, active chlorine and chloride sensors, as well as of the energy harvester and of the predictive software. Feedbacks from lab and field tests were used to prepare the second and third versions of Proteus prototypes to be assembled during the third period of the project. The development of the PNODE second version started out during the second period by the optimization of separate building blocks (optimization of CNT sensor fabrication process, optimization of flowrate sensor design) and new developments (microturbine-based energy harvester, CNT-based hardness sensor, analog/digital CMOS chip).
