Flusso Unveils ‘Smallest’ Air Flow Sensor

Article By : Anne-Françoise Pelé

University of Cambridge spin-off Flusso will start the production of what it claims is the world's smallest flow sensor in the second quarter of 2021.

Flusso, a spin-off from the University of Cambridge, announced it will start the production of what it claims is the world’s smallest flow sensor in the second quarter of 2021. It is part of a digital flow sensing solution targeting high-volume consumer and industrial markets.

Flusso’s FLS110 flow sensor

Flow sensors are traditionally used for measuring the flow rate or quantity of a moving liquid or gas. Measuring 3.5 x 3.5 mm, the FLS110 is a MEMS sensor developed from Flusso’s patented sensing technology on a silicon CMOS wafer. It has no moving parts, is robust, and suited for cost-effective high-volume production of thermal microsensors, the company claims.

“FLS110 is small enough to fit into virtually any product and can be positioned where flow measurement matters the most,” said Andrea De Luca, Flusso’s CEO and co-founder, at the recent MEMS World Summit Webinar – Research and Startups.

Flusso has designed the FLS110 flow sensor to tackle 5 main challenges in air flow measurement: Price (most flow sensors are in the $5+ price tag, which is a barrier for adoption especially in consumer applications); integration complexity (flow sensors typically have form factors that limit product integration); no choice of measurement basis (flow sensors usually measure one basis between flow rate, differential pressure or velocity); a wide range of competing flow measurement and controlling solutions; a long time-to-market.

The FLS110 is part of a digital flow sensing solution seamlessly integrating hardware and software with mechanical and fluidic components. “We provide our customers with a complete digital flow sensing solution comprising not only the central component, but also a full suite of reference designs, covering electronics and firmware aspects, as well as mechanical and fluidic integration aspects,” said De Luca. Proprietary firmware includes sensor control, sensor reading, temperature compensation, and other algorithms. “This modular approach gives our customers the power to find the right balance between performance and system costs required by their end products.”

Flusso’s digital flow sensing solution (Image source: Flusso)

Earlier this year, Flusso received the ISO 9001:2015 certification.

Air quality

With a footprint of 3.5 x 3.5 mm, the FLS110 is suitable for a variety of applications covering 4 main verticals: consumer appliances (e.g., vacuum cleaners, air conditioning units, air purifiers), air management for smart buildings, smoke and fire detection in industrial settings, as well as home healthcare products (e.g., peak flow meters, smart inhalers, breathalyzers, sport performance trainers).

Air quality has become a major concern due to the increasing population density, wildfires, and respiratory diseases. However, the cleaning efficacy of products decreases as filters clog and as motor and moving parts age. “Adjusting the fan speed according to the flow sensor readings, for example, would allow the air purifier to maintain the required efficacy while minimizing power and noise,” said De Luca. Also, filter status monitors help optimize changeovers for an enhanced user experience.

“The evaluation kit plugs into your flow-system using push-fit connectors and into your PC running our GUI for fast sensor evaluation,” said De Luca. Different fluidic fixtures can be ordered to match flow and dP requirements.

Flusso’s next generation of flow sensors will be in the range of between one and two millimeters, said De Luca. “The design isn’t finalized. We are at the proof of concept level.”

Flusso is a fabless semiconductor company. It relies on an external foundry, as well as packaging and testing houses. It is using 6-inch wafers, with “about 6,000 dies per wafer.” De Luca expects to scale up production and reach volumes of about 10 million in 5 years.

In parallel, the startup said it has been working on a thermal conductivity CO2 sensor, a liquid flow sensor, and a flow sensor combined with a metal oxide sensor for breath analysis applications. It has also demonstrated a GaN-on-Si multi-sensing platform for detection, temperature, pressure, and infrared devices. Commenting on the intrinsic properties of gallium nitride, De Luca said, “You have all the mechanical advantages, and it’s chemically more robust than silicon. You also have some level of biocompatibility, as well as superior temperature and radiation hardness.” However, he continued, “Everything comes against cost, and it depends on the application you are targeting.”

Flusso is now looking for partners to implement some of the technologies under development in its laboratories: partners to bring R&D activities from feasibility to product development and partners for ASIC development. “We see two main avenues for which we might need an ASIC partner: One is if we need to provide our customers with an integrated digital solution. The second one is for the thermal conductivity sensors. In that case, there might be a stronger push for having an ASIC integrated within the sensor.”

Flusso was co-founded in 2016 by Professor Florin Udrea (co-founder of CamSemi, Cambridge CMOS Sensors, Cambridge Microelectronics, and Cambridge GaN Devices), Professor Julian Gardner (co-founder of Cambridge CMOS Sensors and Sorex), and alumni John Coull, and Andrea De Luca.

Flusso completed a £5.5 million Series A funding in 2020 from UK technology investment funds. De Luca said the company is preparing a Series B round to finance the next phase of the company, “from initial sales to profitability”.

Headquartered in Cambridge, Flusso has representatives in Hong Kong and in the US. It currently employs 20 people, mostly engineers and semiconductor industry professionals.

This article was originally published on EE Times Europe.

Anne-Françoise Pelé is editor-in-chief of eetimes.eu and EE Times Europe.

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