Esteban Ferro

Wireless sensor mote for snail pest detection

The novelty of this contribution is a custom-made system for snail pest detection that comprises: a shelter to trap snails, a custom photoelectric sensor to detect the snail, a battery and solar cell to power the system, and an Arduino FIO with Xbee to run the Zig-Bee protocol for communication purposes. The ultimate goal is the deployment of a wireless sensor network (WSN) for early snail pest detection to minimize the use of pesticides in crops. Although this is not the first paper on pest detection with WSNs, every pest and scenario needs a specific sensor. In particular, the shape of the shelter discards commercial photoelectric sensors. Also, cost and power consumption lead to the design of a specific conditioning circuitry and strategies to save energy in conjunction with a solar cell to recharge a 1000 mA·h LiPo battery. The battery alone would power the system for 164 days.

The dickson charge pump as voltage booster for light energy harvesting on CMOS vision chips

The photodiode structures on a vision chip can be configured in either imaging (IM) or energy harvesting (EHM) mode. The upper voltage achieved with on-chip energy harvesting is below 0.5 V on standard CMOS technologies, thus DC/DC converters are needed to reach the power supply of today CMOS technologies. This paper addresses the design of a Dickson charge pump to this purpose on a standard 0.18 μm CMOS technology. The paper provides data on how the photoconversion characteristics of the photodiodes change, as well as on how the performance metrics of a CMOS vision chip are affected when the energy harvested in EHM is used as power supply in IM.

Capacitance-based wireless sensor mote for snail pest detection

Pests due to terrestrial mollusks cause serious damage, both economic and ecological, in various types of agricultural plantations. In this paper we develop a low cost capacitive sensor that wirelessly communicates with the base, to monitor the activity of land snails. Once implemented physically, it has been tested in a controlled miniplot with favorable results.

Wireless Sensor Network With Perpetual Motes for Terrestrial Snail Activity Monitoring

Wireless sensor networks (WSNs) are increasingly adopted in agriculture to monitor environmental variables to predict the presence of pests. Differently from these approaches, this paper introduces aWSN to detect the presence of snails in the field. The network can be used to both trigger an alarm of early pest presence and to further elaborate statistical models with the addition of environmental data as temperature or humidity to predict snail presence. In this paper we also design our own WSN simulator to account for real-life conditions as an uneven spacing of motes in the field or different currents generated by solar cells at the motes. This allows achieving more realistic network deployment in the field. Experimental tests are included in this paper, showing that our motes are perpetual in terms of energy consumption.

Live demonstration: Wireless sensor network for snail pest detection

This live demonstration is related to ISCAS track “Sensory Systems: Sensor Networks”. This live demo shows a wireless sensor network of custom-made differential capacitive sensors with the ZigBee protocol for snail pest detection. The wireless sensor network provides the snail occupation level of a given plantation area. Validation of the wireless sensor network in both controlled mini plots in a greenhouse and outdoor small areas has been made.

Dynamic model of on-chip inverting capacitive charge pumps with charge reusing

This paper presents a dynamic model for on-chip inverting capacitive charge pumps driven by two non-overlapping clock signals. The model implements the charge reusing technique to mitigate the efficiency loss due to the charge and discharge process of the parasitic capacitances. Validation with both circuit-level simulations and experimental results is shown, demonstrating high accuracy. An application example in micro energy harvesting is given.

Dynamic joint model of capacitive charge pumps and on-chip photovoltaic cells for CMOS micro-energy harvesting

On-chip energy harvesting by means of integrated photovoltaic cells in standard CMOS technology can be successfully used to recharge or power-up integrated circuits with the use of charge pumps for voltage boosting. In this paper, a tool to facilitate the design of such structures is proposed consisting of an accurate model of the joint dynamics of the micro-photovoltaic cell and a capacitive DC/DC converter in the slow-switching limit regime. The model takes into account both the top and bottom parasitic capacitances of the flying capacitors. We assume a classical model for the photodiode whose photogenerated current is extracted from device-level simulations. The joint model is verified by circuit-level simulations achieving high accuracy and computation time savings of up to 1700×. The joint model shows that the voltage generated by an integrated photovoltaic cell connected to a capacitive DC/DC converter is not constant even under constant illumination. This phenomenon can only be reproduced through the joint model and failing to take it into account results in an error in the estimation of the time needed by the DC/DC converter to reach a given output voltage. We also demonstrate that the maximum output voltage reached by a DC/DC converter in the slow-switching limit regime when a photovoltaic cell is used as energy transducer depends on the switching frequency. Finally, the applicability of the model is illustrated through the optimization of time response and charge efficiency for the Dickson, Fibonacci, and exponential topologies in the case of implantable devices. Copyright