Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - PROTEUS (AdaPtive micROfluidic- and nano-enabled smart systems for waTEr qUality Sensing)

Teaser

PROTEUS investigates the smart integration of chemical and physical sensors based on carbon nanotubes and MEMS with CMOS based electronics and with a cognitive engine providing on-the-fly reconfigurability, applied in the context of water monitoring. Indeed, water management...

Summary

PROTEUS investigates the smart integration of chemical and physical sensors based on carbon nanotubes and MEMS with CMOS based electronics and with a cognitive engine providing on-the-fly reconfigurability, applied in the context of water monitoring. Indeed, water management requires massive, low-cost monitoring means coping with differentiated and evolving requirements. However, the majority of multifunctional water sensors only supports predefined goals hindering interoperability, with a high cost, impeding large scale deployments.
Addressing this, PROTEUS aims at offering x10 reduction in size and unit costs compared to state of the art. To this end, an increased number of functions are integrated into a single sensor node. PROTEUS delivers a reconfigurable MEMS and nano-enabled sensor platform for cognitive water quality monitoring with predictive capabilities and in-built redundancy for increased lifespan. Energy autonomy is achieved by harvesting water flow energy.
The main challenge relates to the heterogeneous integration into a monolithic sensing chip of carbon nanotubes-based resistive chemical sensors, of MEMS physical and rheological resistive sensors and of a multifunctional adaptive deep-submicron CMOS system on chip. Upstream, high level system design addressing industrial use cases, manufacturability and cost-effectiveness, packaging, energy budget and interfaces between building blocks, enables consistency and efficiency of the whole approach. Downstream, system validation is carried out at different levels: benchmarking, reliability assessment, model deployments and field testing.
The consortium brings together renowned actors along the whole value chain, including system integration and end users. This contributes to post-project exploitation prepared by ensuring appropriate inclusion of business requirements within the system design.

Work performed

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).

Final results

At the end of the second period, our progresses beyond SOTA are now at the following stage:
• The massive cointegration of CNT sensors with MEMS sensors on a single monolithic 1cm² silicon chip is at the SOTA in the heterointegration for these technologies, both in terms of number of parameters monitored and number of sensing elements. Some of the sensing elements themselves are novel, notably the flowrate sensor on a silicon platform and the CNT based chloride and chlorine sensors.
• Regarding to the sensor caps assembly, it is the first time that such level of integration (with CMOS and MEMS), packaging, energy harvesting and system level data gathering is achieved for CNT-based water quality sensors (TRL 5). The resulting PNODE surpasses the commercial state of the art in size for multi-parameter sensor chips for water network monitoring.
• Regarding to the 1st CMOS chip, the ADC design is state of the art according to Murmman’s list, while a completely new design for filtering is implemented. The inductor free DC-DC converter based in a switched-capacitor topology is also SOTA-level.
• On the piezoelectric vortex generator for energy harvesting, the results yielded a new understanding of the physics of this type of harvesters; they also open up the possibility to build non-linear equivalent model of the harvester to be used with electronic simulation tool for co-design of the electronic circuitry.
• On software level, Proteus sensor node cognitive capabilities (WSSP Award), notably enabling optimized management of energy supply, though not fully integrated yet with the PNODE, are already state of the art for commercial devices.
• While the deployment in Sense-City water loop clearly makes the SOTA for integrated CNT sensors, the results also show excellent performances for this first version of the full system, with 6 sensors out of 7 operational in tap water and 4 out of 7 already meeting the sensitivity expectations stated by the end users. Note that the validation of Proteus prototypes in Sense-City scale 1 water loop brings from the start a high level of trust in the field relevance of our results.
Significant impacts are expected from our work:
• Patent submission for the CNT sensors is expected during March 2017, while funding strategy for technology transfer will be explored in 2017
• Possible patenting and technology transfer strategies for Proteus analog front end (including both electronic board and CMOS) are being investigated (with preliminary industrial contacts)
• Proteus prediction tools are being incorporated into Wings data analytics platform
• The LORA infrastructure deployed in Almada will be an asset for Almada city to attract field testing opportunities for IoT systems.

Website & more info

More info: http://www.proteus-sensor.eu/.