An Implantable Stimulator with Safety Sensors in Standard CMOS Process for Active Books

This paper presents a second-generation integrated circuit for the Active Books neural stimulation microsystem. It provides multi-channel stimulation with versatile control of stimulation profiles and reduced crosstalk from other stimulation channels. The new design features enhanced safety by monitoring the temperature and humidity inside the micropackage, and the peak electrode voltage at any stimulating electrode. The humidity sensor uses an interdigitated capacitor covered by a passivation layer and a polyimide covering. To boost sensitivity in the operating range of interest, the temperature sensor uses a temperature-insensitive current that is subtracted from a proportional-to-absolute-temperature current. A 3-b analog-todigital converter is used to record the peak electrode voltage. All sensor data is sent to an implanted central hub using bidirectional connection with error checking. Both the stimulation electronics and sensors are integrated on a 6.2 mm × 4 mm silicon die using XFAB's 0.6-μm CMOS high-voltage process. No post-processing steps are involved. The stimulator uses a fivewire cable to provide the power supply and bidirectional data signals. The chip operates from a 7.5-18 V power supply and can generate stimulation currents of 1 mA, 4 mA or 8 mA with a pulse duration of 2 μs-1.07 ms. The humidity sensor output varies linearly with relative humidity (RH) with a normalized sensitivity of 0.04%/%RH over the range of 20-90%RH. The temperature sensor has a nonlinearity of 0.4% over the range of 20-90 °C and a resolution of 0.12 °C. The stimulator is the first of its kind to include integrated temperature and humidity sensors. Index Terms-Active Books, humidity sensor, implant safety, integrated stimulator, temperature sensor, voltage sensor

Set-up and characterization of a humidity sensor realized in LTCC-technology

A new type of integrated temperature and humidity sensor applying LTCC-technology has been developed and characterized. In this approach, sensing elements are implemented using heated metal resistors (Pt-elements), where one is exposed to the humid environment that causes the sensor element to cool down with increased humidity, while the other one is sealed from the environment. Sensor design is based on FEA (Finite Element Analyses) where the critical design parameters have been analyzed with regard to the performance characteristic of the device. The set-up of sensor element will be shown and the functional capability will be demonstrated by experimental results.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing

Development of a New Temperature and Humidity Sensitive Integrated Sensor

研制成由硅温敏二极管和聚酸亚胺湿敏电容集成的温湿度传感器。介绍了它的工作原理、结构设计、制作工艺、测试结果以及为提高它的性能所作的一些研究。An integrated temperature and humidity sensor consisting of the silicon diode and the polyimide-based capacitive humidity sensor has been deve-loped.The sensor working principle, structure design, manufacturing technology, measurement results and some studies of improving the sensor characteristics have been introduced.福建省科技资

The ultimate wearable: Connecting prosthetic limbs to the IoPH

A new wearable device called the 'Ubi-Sleeve' is currently being developed that enables prosthesis wearers and other stakeholders to review temperature, humidity and prosthesis slippage behavior during everyday prosthesis wear. A combination of custom 3D printed strain sensors and off the shelf temperature and humidity sensors will be integrated into an unobtrusive sleeve to create a device that enables a deeper level of understanding of heat and sweat issues. To create the device, a series of experiments are in progress that will quantify changes in heat, humidity and slippage that negatively affect the prosthesis experience. Interviews and focus groups are also being conducted to gain a deeper understanding of the human side of prosthesis wear and to also ensure that data are presented in a way that is effective, useful and easy to understand

Printed-Sensor-on-Chip devices – Aerosol jet deposition of thin film relative humidity sensors onto packaged integrated circuits

In this paper we report on the development of an aerosol jet printed sensing platform integrating elements of silicon and printed electronics. To demonstrate the technology, thin film humidity sensors have been fabricated over the top surface and sides of pre-packaged integrated circuits using a combination of direct-write aerosol jet deposition and drop-casting. The resistive based sensor consists of an aerosol jet deposited interdigitated nano-particle silver electrode structure overlaid with a thin film of Nafion® acting as a humidity sensitive layer. The fabricated sensor displayed a strong response to changes in relative humidity over the tested range (40% RH to 80% RH) and showed a low level of hysteresis whilst undergoing cyclic testing. The successful fabrication of relative humidity sensors over the surface and pins of a packaged integrated circuit demonstrates a new level of integration between printed and silicon based electronics − leading to Printed-Sensor-on-Chip devices. Whilst demonstrated for humidity, the proposed concept is envisaged to work as a platform for a wide range of applications, from bio-sensing to temperature or gas monitoring

Porous Alumina Based Capacitive MEMS RH Sensor

The aim of a joint research and development project at the BME and HWU is to produce a cheap, reliable, low-power and CMOS-MEMS process compatible capacitive type relative humidity (RH) sensor that can be incorporated into a state-of-the-art, wireless sensor network. In this paper we discuss the preparation of our new capacitive structure based on post-CMOS MEMS processes and the methods which were used to characterize the thin film porous alumina sensing layer. The average sensitivity is approx. 15 pF/RH% which is more than a magnitude higher than the values found in the literature. The sensor is equipped with integrated resistive heating, which can be used for maintenance to reduce drift, or for keeping the sensing layer at elevated temperature, as an alternative method for temperature-dependence cancellation.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/16838

Automation of closed environments in space for human comfort and safety

The development of Environmental Control and Life Support Systems (ECLSS) for Space Station Freedom, future colonization of the Moon, and Mars missions presents new challenges for present technologies. ECLSS that operate during long-duration missions must be semi-autonomous to allow crew members environmental control without constant supervision. A control system for the ECLSS must address these issues as well as being reliable. The Kansas State University Advanced Design Team is in the process of researching and designing controls for the automation of the ECLSS for Space Station Freedom and beyond. The ECLSS for Freedom is composed of six subsystems. The temperature and humidity control (THC) subsystem maintains the cabin temperature and humidity at a comfortable level. The atmosphere control and supply (ACS) subsystem insures proper cabin pressure and partial pressures of oxygen and nitrogen. To protect the space station from fire damage, the fire detection and suppression (FDS) subsystem provides fire-sensing alarms and extinguishers. The waste management (WM) subsystem compacts solid wastes for return to Earth, and collects urine for water recovery. The atmosphere revitalization (AR) subsystem removes CO2 and other dangerous contaminants from the air. The water recovery and management (WRM) subsystem collects and filters condensate from the cabin to replenish potable water supplies, and processes urine and other waste waters to replenish hygiene water supplies. These subsystems are not fully automated at this time. Furthermore, the control of these subsystems is not presently integrated; they are largely independent of one another. A fully integrated and automated ECLSS would increase astronauts' productivity and contribute to their safety and comfort

Integrated Temperature and Humidity Control: A Unique Approach

During hot and humid periods, a comfortable indoor environment can be attained only by controlling both the dry-bulb temperature and the humidity in the space. Conventional thermostats control the ON/OFF status of a cooling plant to maintain only the dry-bulb temperature within the conditioned space. This can result in the space dew-point temperature increasing to uncomfortable levels, especially during cool and humid times of the day and/or when there is high latent gain. Consequently, the occupant must resort to undesirable and inefficient interventions (e.g., manually lowering the space dry-bulb temperature set point) to "sweat out" the water from the air. An innovative controller, the Integrated Temperature and Humidity Controller, has been invented for controlling both the dry-bulb temperature and the absolute moisture content of the air in a conditioned space. These new algorithms have been implemented in a product prototype, and limited field tests have been performed. Preliminary results confirm the expected operation and performance of the controller and its robustness and are extremely encouraging

New Electronic Interface Circuits for Humidity Measurement Based on the Current Processing Technique

The paper describes a new electronic conditioning circuit based on the current-processing technique for accurate and reliable humidity measurement, without post-processing requirements. Pseudobrookite nanocrystalline (Fe2TiO5) thick film was used as capacitive humidity transducer in the proposed design. The interface integrated circuit was realized in TSMC 0.18 mu m CMOS technology, but commercial devices were used for practical realization. The sensing principle of the sensor was obtained by converting the information on environment humidity into a frequency variable square-wave electric current signal. The proposed solution features high linearity, insensitivity to temperature, as well as low power consumption. The sensor has a linear function with relative humidity in the range of Relative Humidity (RH) 30-90 %, error below 1.5 %, and sensitivity 8.3 x 10(14) Hz/F evaluated over the full range of changes. A fast recovery without the need of any refreshing methods was observed with a change in RH. The total power dissipation of readout circuitry was 1 mW

Modelling of a poultry shed

Tegel Foods is New Zealand’s leading producer and supplier of poultry products, providing an extensive range of quality poultry products to New Zealanders for over thirty years. Tegel is a fully-integrated poultry producer involved in breeding, hatching, feeding, growing, processing and marketing of chicken and turkey in New Zealand. The problem presented by Tegel was specifically to model the energy exchange between the chickens and their shed environment in order to better understand and control the shed climate and thereby maximize growth rate. A model for the heat production and water respiration rate of a typical chicken was developed, based on physical principles. A thermodynamical model of the whole chicken+shed system included the temperature of the external air, the internal air, the chickens, the litter, the concrete floor and the underlying soil. It also included the relative humidity (RH) of the external and internal air and the water flows into and out of the shed. Modelling of the shed environment’s inputs and outputs will be particularly valuable for continuing assessment of three fundamental inputs of economic importance: feed nutrient density in terms of energy formulation, heating in terms of gas/power usage, and heat removal via extraction fans. Optimisation of liveweight gain and feed conversion potential are the end targets