Air quality, for long a hot topic due to its association with the health of the environment and individuals, has been boosted further up the agenda of governments, businesses and individuals by the pandemic.
It is well documented that poor outdoor air quality is linked to a significant detrimental effect on long term health and can also exacerbate existing health conditions. Some studies have highlighted patients with COVID are at greater risk of suffering more severe complications if they have experienced long term exposure to poor air quality.
As a result, there is now renewed focus on gas sensors for measuring air quality. Pete Bailey, Field Applications Engineer at Anglia introduces a Renesas platform that offers customers access to decades of knowledge, know-how and data allowing them to create low power and high accuracy IoT-ready gas and air quality monitoring solutions.
The importance of air quality
Poor air quality is commonly associated with outdoor environments where pollutants from vehicles and factory emissions are known contributors, however indoor air quality is also becoming a very important consideration particularly in public buildings such as schools and offices but also domestic environments where it is beneficial to have good air quality for health benefits and comfort reasons. Modern buildings are designed to be well insulated to reduce their impact on the environment, however unless provisions are also made for adequate ventilation these environments can have an increased build-up of pollutants in the air. The source of these indoor pollutants is many and varied and range from cooking odours, CO2 and aerosols. Sensors that can reliably and accurately measure air quality can play an import role in the future of building and ventilation control systems. There is a further specific challenge in monitoring air quality in refrigerated storage facilities, where odours can both affect the taste of the stored food, and be an indicator of issues such as decay.
The Renesas ZMOD platform
Renesas are at the forefront of air quality sensing with their ZMOD gas sensor platform the industry’s most accurate and flexible gas sensing platform. These integrated digital sensor modules provide best-in-class stability and sensitivity for indoor air quality (IAQ), outdoor air quality (OAQ) and refrigeration air quality (RAQ) monitoring. In addition to being chemically and electrically calibrated, the platform’s flexible interface enables software configurable indoor, outdoor, and refrigeration air quality sensing solutions. Renesas' gas sensors are capable of accurate detection of Volatile Organic Compounds (VOCs), nitrogen oxides (NOx), ozone (O3), hydrogen (H2), and other flammable gases, and utilise advanced sensing materials with more than 15 years of proven stability and reliability. The platform benefits from Renesas rich history of developing precision ASICs that are accurate, energy-efficient, and provide maximum flexibility through software-configurability. The combination of this ASIC design experience for the sensing control and their sensing materials expertise are the strengths on which the capabilities of the ZMOD platform rest.
The ZMOD platform, then, exploits three key factors: materials, temperature, and time. The MOx material delivers outstanding sensitivity to air quality contaminants, with a well-controlled manufacturing process developed and demonstrated over many years.
The ability to vary operating temperature and time at temperature rest on the capabilities of the Renesas ASIC. The ZMOD platform leverages these three critical parameters to create a tuneable system for reliable detection of a wide range of target gases to optimize sensitivity and provide the ultimate firmware-enabled gas detection platform for indoor, outdoor and refrigeration applications alike.
The ZMOD platform sensors are resistant to contamination and siloxanes, commonly used in cleaning solvents, and each sensor module is electrically and chemically tested and calibrated during manufacture. The sensors have an I²C interface allowing measurement results to be read directly by the applications microprocessor, which can then be used to process the data to determine the levels of gases present.
Indoor Air Quality
The ZMOD4410 module is Renesas’ Indoor Air Quality (IAQ) platform which features embedded artificial intelligence (AI) with machine learning for accuracy and part-to-part consistency, the sensor is designed to detect trace gases in various locations within indoor environments. The sensor output based on AI machine learning algorithms allows measurement of total organic compounds (TVOC) concentrations, estimated carbon dioxide level (eCO2), and features an algorithm to set a control signal to trigger an external action based on IAQ and odour change and to also discriminate for sulphur-based odours.
The ZMOD4410 IAQ gas sensor module is supplied with pre-compiled firmware libraries that can be run on Renesas’ proprietary and ARM based microcontroller platforms, such as the RL78 or latest ARM RA2E1 entry line general purpose MCUs. These firmware libraries are suitable for mobile, industrial, and consumer applications. The behaviour of the sensor can be configured using these firmware libraries allowing designers to tailor products for individual room applications, such as smart odour sensing for ventilation systems, bathroom and kitchen monitoring and controls, and air quality monitors to help solve unique air quality problems.
The ZMOD4410 IAQ sensor also features a low power configuration to support battery powered applications where sensors are to be deployed remotely, in low power operation the sensor consumes less than 1.5 mW. A new ultra-low power firmware update has also been released which can lower current consumption even further to typ. 0.2mW (Av). Furthermore, the sensor is available in an optional IP67 rated waterproof package which is designed with an integrated hydrophobic membrane to protect the sensor from harsh environments.
Having IP67 rated water and dust protection directly implemented in the sensor package makes the sensor extremely easy to integrate, especially in kitchen, bathroom and even outdoor applications or any environment where the sensor could be exposed to direct contact with water and dust.
The ZMOD4410 IAQ sensors have third-party certification for compliance with standards defined by the German Environment Agency (UBA) and best available eCO2 technology.
Outdoor Air Quality
For Outdoor Air Quality applications Renesas’ ZMOD4510 platform is the industry’s first digital OAQ sensor module, it is calibrated to detect ozone (O3) and nitrogen oxide (NOx) gases that contribute to unhealthy outdoor air quality. The ZMOD4510 has the ability to quantify combined ozone and NOx in concentrations as low as 20 parts per billion (ppb), coupled with its outstanding combination of flexibility and small size, makes it an ideal air quality sensor solution for a wide variety of industrial and consumer applications. For example, these sensors could be easily integrated into existing “Roadside infrastructure” equipment such as street lighting, road signage or electricity substations, providing additional product functionality and service features to the applications.
The ZMOD4510 OAQ sensor also has improved energy efficiency making it suitable for battery powered solutions and features high sensitivity and reliability. Complementing these advantages, the ZMOD4510 can be quickly integrated into designs thanks to the supplied pre-compiled firmware and the pre-calibration of the sensors, these attributes help reduce design timescales and lower production costs.
The ZMOD4510 OAQ sensors provide reliable detection that correlates with the US Environmental Protection Agency’s (EPA) Air Quality Index (AQI) for measuring ozone and NOx gases.
Refrigeration Air Quality
The ZMOD4450 integrated digital gas sensor module for refrigeration air quality (RAQ) applications enables designers to add new odour detection and mitigation capabilities to refrigerators for consumer and industrial scale operations. Like the other ZMOD platforms the ZMOD4450 is software configured to sense a wide variety of gases that produce odours, affect food taste or cause foods to spoil prematurely. Early detection of these gases – ethylene, hydrogen sulphide, dimethyl sulphide, trimethylamine, and more – enables identification of spoiled food so it can be discarded before it affects other foods in the refrigerator.
The Renesas’ ZMOD sensor platforms have been designed to provide vital information that helps individuals manage their health and daily activities, as well as enable systems to efficiently manage smart air handling and measurement systems in buildings, factories, refrigeration systems, outdoor environments and in the home.
With more than 20 years of industry experience, Renesas is an expert in providing sensor technologies that enable customers to design and build best-in-class sensor solutions. In addition to gas and air quality sensors, the Renesas line-up includes flow, humidity, temperature, position, proximity and Bio sensor products, they continue to expand the breadth of sensor technologies available with new unique and differentiated sensor solutions. Anglia offer comprehensive support for customer designs on the full range of Renesas sensors, with free evaluation kits and samples of Renesas products via the EZYsample service which is available to all registered Anglia Live account customers.
In addition, Anglia’s engineering team have extensive experience of working with air quality and other sensor designs and are on hand to provide valuable product demonstrations, insight, advice, and component recommendations for your application. This resource is available to support customers with all aspects of their designs, offering hands on hardware and software design support along with access to an extensive resource of technical application notes and expertise from Renesas.
Visit www.anglia-live.com to see the full range of Renesas products available from Anglia.