Ambient air sensor module useful for COVID-19 prevention developed by Alps Alpine & Sensirion
28 June 2021
Fig. 1. Alps Alpine develops Ambient Air Sensor Module useful for COVID-19 prevention
Sensor module provides monitoring of the surrounding environment with high-accuracy sensing of CO2, temperature, humidity and other parameters – making it useful as part of COVID-19 prevention measures.
Alps Alpine has a developed an Ambient Air Sensor Module to perform high-accuracy sensing of carbon dioxide (CO2) concentrations, temperature and humidity in the immediate surrounding environment. The module could be used in places like restaurants and entertainment facilities to monitor indoor ventilation, temperature and humidity indoors, as part of COVID-19 prevention measures.
Other sensors can be included, too, for detection of PM2.5, volatile organic compounds (VOCs) and alcohol. Alps Alpine will proceed with market research with a view to deployment of the module for diverse applications, such as energy-saving functionality in major appliances to help combat global warming and automotive features to stop drivers falling asleep at the wheel, contributing to safe mobility. Mass production is scheduled to begin in 2022.
Background to the development
Despite progress made in the development of vaccines, there is still no end in sight for the global COVID-19 pandemic. Japan’s Ministry of Health, Labour & Welfare has suggested three characteristics common among places where clusters of infections emerge – they are closed spaces with poor ventilation; they are crowded with many people; and people engage in conversation or speech there in close proximity (within arm's reach).
Various strategies have been introduced to prevent infections. For example, businesses operating spaces where people gather in close quarters, such as restaurants and entertainment facilities, have limited entry, shortened hours, implemented hand sanitising and temperature taking, and ensured ventilation.
Fig. 2. Size comparison_Sensirion NDIR & PAS sensors
In regard to ventilation, in particular, ensuring constant ventilation with windows or doors open the whole time can affect the temperature and humidity inside, making it difficult to maintain a pleasant environment. The other option is routine ventilation, with priority placed on regulation of temperature and humidity. The problem here, though, is it is hard to tell whether the level of ventilation is actually effective in preventing virus transmission. This has heightened the need for high-accuracy CO2 sensors – for determining optimal ventilation timing – and high-accuracy temperature and humidity sensors – to help restore comfortable conditions after the disruption caused by ventilation.
Alps Alpine has advantages in the sensor technology domain, and has developed sensors to measure changes of a wide range of parameters besides CO2, temperature and humidity, including air pressure, load and electric current. These sensors have been integrated into diverse products, such as automobiles, consumer electronics, smartphones and industrial equipment. Using this expertise, Alps Alpine has developed a Ambient Air Sensor Module that can contribute to COVID-19 prevention.
Outline of the development
The Ambient Air Sensor Module was developed through its strategic partnership with manufacturer of digital microsensors and sensor systems, Sensirion. The module detects ambient CO2 concentrations and temperature and humidity levels with high accuracy and will help to prevent COVID-19 transmission while maintaining a comfortable indoor environment.
Fig. 3. The CO2 sensor inside the Ambient Air Sensor Module employs photoacoustic spectroscopy (PAS)
Specifically examining the CO2 sensor, many existing products employ non-dispersive infrared (NDIR) spectroscopy. The CO2 concentration is determined from the change in the amount of infrared light absorbed by CO2 molecules between an IR emitter and receiver. The large size of sensors is an issue given that detection accuracy corresponds to the distance the infrared light has to travel. Another concern with the NDIR method is the potential for the axis of the emitted infrared light to shift during end-product design or transportation, leading to detection errors.
The CO2 sensor inside the Ambient Air Sensor Module employs photoacoustic spectroscopy (PAS) (see Fig.3). Here the CO2 concentration is ascertained from the sound of CO2 molecules captured by a microphone as they vibrate on contact with emitted infrared light.
Because detection accuracy is not dependent on the distance travelled by the infrared light, Alps Alpine managed to maintain high accuracy while realising a compact sensor measuring 10.1 × 10.1 × 6.5mm. And because there is no longer a need to place a detector opposite the IR emitter, as is the case with an NDIR sensor, external impacts will not have an effect, enabling stable performance.
Expertise in module creation built up through many years of sensor development was also utilised to offer customers the option, depending on their requirements, of including VOC and alcohol sensors in addition to the CO2 and temperature and humidity sensors. This lessens the burden for customers in end-product design and supports diverse needs for additional functions depending on the application.
Fig. 4. Alps Apine Ambient Air Sensor Module Specifications
Outlook
Besides monitoring of ventilation in places like restaurants and entertainment facilities, Alps Alpine foresees effective use in a wide range of applications, such as energy-saving functionality in major appliances and automotive features to stop drivers falling asleep at the wheel. Market research will be conducted both in Japan and globally with aims to achieve sales in excess of 1 billion Yen during fiscal year 2023 (the year ending March 31, 2024). Market deployment of the module will help fight both COVID-19 transmission and global warming and also contribute to safe mobility. To that end, Alps Alpine is innovating value for humans and society on a brighter planet.
Principal applications
• Products related to the ambient air environment
• Major appliances
• Household equipment
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