FEATURE SENSORS & SENSING SYSTEMS
INTEGRATING GAS SENSORS into everyday consumer devices
Concerned about their health, consumers today are becoming more and more interested in monitoring air quality. To help, Cambridge CMOS Sensors has introduced a digital gas sensor designed for easy integration into applications such as smartphones, wearables, smart homes and HVAC systems. Rachael Morling reports
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Consumers today are faced with reports from organisations such as the Royal
College of Physicians and The Journal of Environmental Health Perspectives which show that long-term exposure to indoor pollutants such as VOCs – harmful gases found indoors – can have a detrimental impact on health, even at low levels,” comments Jess Brown, sales and marketing director of Cambridge CMOS Sensors. “They’ve been left wondering whether it is poor air quality which is affecting their decision-making and making them feel tired and unwell.” As a result of this, consumers are
becoming more interested in monitoring air quality so that they can take action to avoid negative health effects. To help, the company has launched
the CCS811, the first digital product in its CCS800 family of ultra-low power miniature gas sensors. This integrates a metal oxide gas sensor with a microcontroller sub-system which enables indoor air quality monitoring. “The low power consumption and
compact size of the CS811 has created new opportunities to develop applications in the consumer market,” Brown explains. “Target applications include smartphones, tablets, smart homes, HVAC systems, wearables and accessories.” The CCS811 detects VOCs which
are gases typically found in indoor environments. They can be emitted by everyday objects like paint and new furniture, and are a common cause of bad air quality. It is therefore crucial that they can be detected. So, integrating gas sensors into everyday consumer devices such as smartphones gives the user the ability to monitor the air quality of their local environment wherever they go, without having to carry expensive specialist equipment. “You could, for example, check the air quality of a hotel room simply by using the sensor in your phone,” says Brown.
THE DIGITAL SOLUTION Many popular designs of IoT devices, smartphones and tablets use digital
16 MAY 2016 | DESIGN SOLUTIONS
architecture and sensor hubs which interact with all the sensors in the device, processing the information received without the need for additional processing power. The CCS811 uses a standard digital interface which is compatible with these sensor hubs. This means that it can be easily added to the processing systems of popular consumer devices where analogue sensors would require additional components. The CCS811 also has an integrated MCU
which runs all the algorithms necessary for gas detection. Its on-board processing reduces the overall system power consumption and processing required on the host system. This allows for simple integration into consumer devices and fast design times without the need for external components. The sensor is based on the company’s
Micro-hotplate technology. Brown explains what this is: “Our Micro- hotplate technology is the core IP behind all of our sensors. It is this technology which allows our sensors to be very small with low power consumption, critical for integrating into consumer products. The Micro-hotplate is also very robust, meeting the requirements for the harsh environments it could get subjected to in these applications.
With its low power consumption and
compact size, the sensor is suitable for use in smartphones, tablets, smart homes, HVAC systems, wearables and accessories
“In addition, because of our Micro-
hotplate technology, we can manufacture sensors in high volumes using a standard semiconductor manufacturing production process rather than using an expensive specialist MEMS foundry.”
EMPOWERING THE USER Harmful gases within indoor environments can cause poor air quality which is damaging to human health. According to Brown, having a sensor which can monitor the local environment empowers the user to make decisions which can improve air quality, such as opening a window, turning on the ventilation or even finding out where the gases are being emitted from.
Cambridge CMOS Sensors
http://ccmoss.com
AT A GLANCE GUIDE TO THE CCS811 SENSOR C digital interface, all inside a compact 2.7 x 4.0mm, 0.6mm LGA package
CCS811 functions include: A metal oxide (MOX) gas sensor, a microcontroller, an Analogue-to-Digital converter (ADC) and an I2
suitable for low cost PCB technology. Detecting Ethanol and Hazardous Gases: CCS811 can be used for detecting Ethanol (Alcohol) and hazardous gases such as Carbon Monoxide (CO) and a wide range of Volatile Organic Compounds (VOCs). Optimised low-power modes: CCS811 supports multiple measurement modes which have been optimised for low-power consuming <1.2mW on average during active sensor measurement per minute and <6uW in idle mode. Integrated MCU: It supports an integrated MCU that manages the sensor drive modes, ADC measurements and processes raw sensor data during gas detection using intelligent detection algorithms to represent equivalent CO2
(eCO2 ) level or TVOC measurement in real world environments, where the
main cause of VOCs is from humans. This on-boarding processing reduces the overall system power consumption and processing required on the host system. Digital Interface: CCS811 supports a standard I2
C digital interface compatible with application processors,
and provides a highly integrated solution. Compared to using separate gas sensor and microcontroller chips, which typically require two or more additional components, the CCS811 can save on the device’s bill of materials (BOM) and up to 60% on the board footprint.
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