The next generation of gas sensors are highly integrated devices, are available in miniature sizes, and feature stability and sensitivity while simultaneously measuring nitrogen oxides, ozone, carbon monoxide, sulfur dioxide, hydrogen sulfide, methane, formaldehyde, and other gases.
Gas sensors, once restricted to industrial applications aimed at ensuring air-quality control for workers’ safety, first expanded to facilitate energy efficiency in heat, ventilation and air conditioning (HVAC) systems and then extended their reach to air-quality monitoring for both indoor and outdoor environments.
That includes personalized environmental monitoring in homes, buildings, factories, and car cabins for specific detection of volatile organic compounds (VOC), volatile sulfur compounds (VSC), and other gases. Take the example of ZMOD4410 gas sensor from Integrated Device Technology Inc. (IDT), now a Renesas company.
Intelligent Gas Sensors
IDT’s ZMOD4410 gas sensor is an ASIC (application-specific integrated circuit)-based hardware platform that has integrated software configurability to enable new sensing capabilities on a single platform. The firmware in ZMOD4410 allows designers to configure gas sensors in a way that, for instance, they can indicate the presence of odors in kitchens and bathrooms.
Therefore, gas sensors can detect VOC gases in individual rooms by employing the algorithms that enable sensors to learn the standard environment of these rooms and report changes in gas levels. In other words, the firmware translates into a mode of operation to allow gas sensors to be upgraded for various gases and odors. The ZMOD4410 gas sensor, for example, can monitor TVOC, eCO2, and odors in the home.
The ZMOD4410 gas sensor is electrically and chemically tested to ensure consistency and stability. Image from IDT
That makes these gas sensors highly suitable for automatic exhaust fans and other air-changing systems. Moreover, they can serve a wide array of air quality applications ranging from smart thermostats to air purifiers to smart HVAC equipment.
Gas Sensor Interface
Another design solution worth mentioning is a sensor interface IC that incorporates potentiostat and Electrochemical Impedance Spectroscopy (EIS) functionality on a single chip. The ADuCM355 interface chip comprises a precision analog microcontroller that consumes low power and operates at low noise to effectively serve industrial gas sensing, instrumentation, vital signs monitoring, and disease management.
The block diagram of Arm Cortex™ M3 processor-based ADuCM355 interface chip designed to control and measure chemical and biosensors. Image from ADI
Unlike traditional solutions using multiple ICs, ADI’s single-chip solution can better serve portable gas detectors made available in much smaller form factors. That’s crucial for ultra-miniature gas sensors being integrated into mobile devices, wearables, and IoT devices for smart city and smart home applications.
The EVAL-ADuCM355 eval board for the ADuCM355. Image from ADI
PalmSens, a supplier of interface modules, has incorporated ADI’s ADuCM355 chip in its general-purpose Electrochemical Interface Module for portable, wearable, and space-constrained sensor applications. PalmSens claims that the EmStat Pico module comes in an ultra-compact form factor and carries out measurement in minutes.
Where do gas sensors fit into your work? Are there any particular challenges you've found are associated with designing a gas sensor device or system? Share your experience in the comments below.