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2021 Top Digital Nose Gas Sensors



Protecting businesses, customers, or households requires using the right equipment. That’s why there’s a constant need for businesses and homeowners to invest in high-quality gas detectors. Gas Detection is often required or desirable for different reasons. A gas monitoring system helps prevent an explosion or prevent staff injury or exposure to toxic gases in factories or workplaces. In homes, it can help detect gas leaks that can lead to a fire.

Gas monitors can initiate actions to help prevent gas levels from rising further. Actions can include automatic shutoff of gas valves, shutting down a process, turning on a ventilation fan, or audible and visual alarms to alert and evacuate people. Gas monitors are also used for process control.

Here are some very good digital nose gas sensors.

Renesas ZMOD4410

Source | Datasheet

The ZMOD4410 Gas Sensor Module is designed to detect total volatile organic compounds (TVOC) and monitor indoor air quality (IAQ). It is a 12-pin LGA assembly that consists of a gas sense element and a CMOS signal conditioning IC. An additional package supporting waterproof IP67 rating is also available. The module’s sense element consists of a heater element on a Si-based MEMS structure and a metal oxide (MOx) chemiresistor. The signal conditioner controls the sensor temperature and measures the MOx conductivity, which is a function of the gas concentration.

The firmware enables different ZMOD4410 features based on traditional and machine learning algorithms with embedded artificial intelligence (AI). This is used to determine the TVOC concentration, IAQ rating, and estimated carbon dioxide (eCO2) level. The ZMOD4410 algorithm can discriminate between sulfur-based odors or generate a control signal, triggering actions based on total odor levels. The ZMOD4410 is an excellent choice for low-voltage and low-power battery applications thanks to its low operating current consumption in Low Power Operation Mode. Built-in nonvolatile memory (NVM) stores the module configuration and calibration data.

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Sensirion VOC Sensor SGP40

The SGP40 is Sensirion’s new digital VOC (volatile organic compounds) sensor designed to integrate into air purifiers or demand-controlled ventilation. Based on Sensirion’s CMOSens® Technology, the SGP40 offers a complete sensor system on a single chip. It features a digital I2C interface, a temperature-controlled micro-hotplate, and a humidity-compensated indoor air quality signal. Combined with Sensirion’s VOC Algorithm (part of the SGP40 VOC Index driver package), the sensor signal can be directly used to evaluate indoor air quality, e.g., for triggering the gradual fan control of an air treatment device.

Both the SGP40 chip and VOC algorithm feature robustness in the final application over their lifetimes. SGP40 enables a drastic reduction in power consumption, making it suitable for battery-driven applications as well. Sensirion’s state-of-the-art production process guarantees high reproducibility and reliability.

Source | Datasheet

IDT (Renesas) SMOD707

Integrated Device Technology originally developed the SMOD707 before Renesas acquired the company. The SMOD707 is a complete smart sensing solution for general volatile organic compounds (VOCs). The module, consisting of the SMOD smart sensing platform combined with IDT’s SGAS707 VOC sensor, indicates total VOCs measured both as resistance and as a linear response proportional to a representative VOC calibration gas (ethanol). The SMOD707 communicates with an external controlled or a data logger through a USB interface, and it can be supplied with an I2C or UART interface via special order. The SGAS707 sensor can be supplied separately from the SMOD707 Smart Sensing Module. See the SGAS707 Datasheet for more information.

Source | Datasheet

Bosch© BME

The BME688 is Bosch©’s latest gas sensor version that adds artificial intelligence capability on-sensor coupled with a gas scanning feature that detects volatile sulfur compounds (VSCs). Bosch© claims that BME688 is the first digital gas sensor with AI, which is ideal for developing new applications. They claim it can be customized for specific use cases, such as detecting spoiled food, bad breath, and even forest fires.

The 4-in-1 MEMS sensor is developed to measure gases, humidity, temperature, and barometric pressure in a single compact package (pictured above) to lessen the total cost of ownership (TCO).

Bosch© is currently one of the market-leading sensor providers. Hence, it’s no surprise that the new BME688 offered top-tier performance based on the proven BME680 platform, enhanced by new AI capabilities.

The development of this sensor factored in the current pandemic situation. Bosch© affirms the need to be confident that the air around us is clean and safe to breathe at home, in the office, or outdoors. COVID-19 highlighted the importance of air quality. Poor air quality has an increasingly negative effect on our health and well-being due to the particulates, gases, and airborne viruses present in our modern environment.

Sample use cases:

  • Indoor and outdoor air quality measurement
  • Bad breath and spoiled food detection based on the measurement of volatile sulfur compounds, which serves as an indicator of bacterial growth
  • Detection of unusual smells and gases, which can indicate fire or leakage
  • Diaper state detection for use in baby care
  • Wildfire detection

The gas sensor in the BM688 has an overall sensitivity and reacts to most volatile compounds and many other gases polluting indoor air. The intensity of the signal typically scales with the chemical reactivity of the gases. In contrast to sensors selective for one specific component, the BME688 can measure the sum of VOCs/contaminants in the surrounding air. This enables the BME688 to detect, e.g., outgassing from paint, furniture, and garbage, high VOC levels due to cooking, food consumption, exhaled breath, and/or sweating.

The BME688 has been specifically developed for mobile and connected applications where low power consumption and size play a vital role. The sensor is housed in a small housing, measuring just 3.0 x 3.0 x 0.9 mm3. Power consumption can be configured between 2.1 µA and 11 mA based on the required functions and data rates and optimized using the BME AI-Studio.

Factors That May Affect a Gas Sensor’s Life

Traditionally, temperature extremes can affect a sensor’s life. Manufacturers typically state an operating temperature range for the instrument: -30°C to +50°C. High-quality sensors can withstand brief excursions beyond these limits. However, repeated high temperature exposure can result in evaporation of the electrolyte and possible shifts in the baseline (zero) reading, and slower response.

Sensitivity can also be lost at low temperatures; sensors may operate down to -40°C but become significantly less sensitive to gas and take much longer to respond. There is also a risk the electrolyte will freeze below -35°C. Exposure to very high gas concentrations can also compromise sensor performance. The most significant impact on sensor life is humidity. The ideal condition for electrochemical sensors is 20°Celsius and 60%RH (relative humidity). When the humidity increases beyond 60%RH, water will start absorbing into the electrolyte, causing dilution. In extreme cases, potential leakage from the sensor body can occur and then through the pins. Below 60%RH, water in the electrolyte will begin to dehydrate. The response time may be significantly extended as the electrolyte is dehydrated. The humidity limitation makes these devices suited for indoor use, but not for long-term outdoor use.

Other Applications

Many factories, plants, parking garages, storage facilities, and a wide variety of other locations have the potential to have vapors or toxic gases present. Gas monitoring devices, aka digital noses, enable businesses and the general populace to solve gas monitoring safety-related applications.

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Are you looking to build an FDA-approved wearable medical device? You can entrust your wearable technology product design to Voler’s expert low-power design team. Voler’s experts combine decades of electronic design experience on hundreds of projects across a wide spectrum of sensors, power, and wireless communication. We are sensor experts and have developed many wearable technology products and medical devices by managing the design trade-offs between size, power, and cost. We select the best wireless standard for your application.

About Voler

Located in Silicon Valley and with more than 40 years of electronic design experience, Voler Systems continues to be a leading custom product design consulting company providing high-quality electrical engineering and firmware development. Voler Systems ensures delivery of quality products, on time, on budget with low risk. All projects are undertaken with good specifications, the right people, quality design, constant communication, and a smooth transfer to manufacturing.




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