Imagine a machine smaller than a square millimetre. A machine capable of detecting the subtlest changes in movement, atmosphere, chemical composition, pressure and even gravitational pull - a tiny device able to trigger action that can alter events and save lives.
We’re describing a MEMS sensor. A sensor that is a micro-electro-mechanical system, an innovation that is making the machines and devices we rely on in many different settings more compact, responsive and intelligent than ever before.
What are examples of MEMS sensors?
The accelerometer in your phone that detects your movements and counts your steps? That’s a MEMS sensor. When your car’s airbag inflates? It’s the delicately calibrated MEMS sensor that has responded to the vehicles sudden deceleration and signalled the need for action.
But MEMS sensors have countless other capabilities and applications. They are the miniature gyroscopes, digital thermometers, proximity detectors, microphones and so-called ‘labs in chips’ that are continually gathering and relaying information from their immediate environments and the wider world. They are powering the central brains of devices in automotive, manufacturing, medicine, heavy industry and the home.
In doing so, they’re replacing flawed and inaccurate human judgement calls. They are saving us effort and reducing risk; sensing the subtlest changes in conditions to help us optimise our real-world responses, preventing accidents and saving lives.
But what weird and wonderful directions can we expect MEMS sensors to take us in the years to come?
1. A breath of fresh air?
Gas and atmospheric detection promises to be a rich seam of commercial opportunity for the producers of MEMS sensors in the future.
Bosch’s MEMS sensor BME688 is the first sensor “that combines gas, humidity, temperature and barometric pressure sensing with innovative artificial intelligence” to replicate the action of the human nose.
Developers can adapt the MEMS and teach it to recognise and act on a range of noxious odours in various concentrations. Applications include such diverse use cases as early forest fire detection and warning of Covid risk in under-ventilated spaces. And what about refrigerators that detect rotting vegetables to prompt action on food waste? Or personal wearables that sense and alert owners to their own bad breath or body odour?
2. Driverless cars
Adaptive cruise control and automatic emergency braking systems are part of the onward march towards fully autonomous vehicles. Visual sensors alert the vehicle to act on the driver’s behalf to adjust the vehicle’s throttle and/or apply the brakes, maintaining a safe distance from other vehicles and avoiding collisions. Optical MEMS, especially micro-mirrors, are playing a key role in steering laser beams and gathering reflected light to trigger these driverless solutions.
But some automotive developers are pointing out it's not just visual sensors that will be critical to safer driverless tech. Aural sensors (giving cars the ability to hear as well as see road conditions) is one way in which they can become even more capable at predicting issues and making appropriate driving decisions on our behalf.
3. MEMS in Space
Thanks to their compact nature, low power usage and long battery life, MEMS are helping control the ultimate driverless vehicles, unmanned satellite and spacecraft. As the earth’s orbit becomes more and more cluttered by space junk the chance of collision and damage of expensive satellites becomes more acute. MEMS sensors are being deployed to alert navigation devices about collision threats and steer spacecraft away from interstellar trouble.
4. An eye for an eye
In healthcare MEMS sensors are being helping identify glaucoma and other eye disorders. Ultra-miniaturized sensors sitting on contact lenses can be used to measure cornea deformations due to Intra-Ocular-Pressure (IOP) variations. The IOP Sensor is a wireless sensor that acts as a transducer, antenna and mechanical support for additional read-out electronics. This information can be monitored and analysed by a clinician to take necessary action and diagnose glaucoma in its earliest stages.
5. Labs on chips
So-called BIOMEMS are bringing data direct to diabetic patients, too, in easy to use, responsive, and highly portable formats :
“The glucose sensor developed by the Southwest Center for Microsystems Education uses a micro transducer of about 1mm long by 200 µm wide to sense blood glucose levels. When a drop of blood is placed onto the transducer, the coating on the transducer begins a glucose oxidation reaction with the glucose in the blood plasma. The electrons produced by this reaction becomes a current that is measured by the device and converted to a glucose level reading.”
This market is booming, MEMS are revolutionising self management potential for people with chronic medical conditions, helping them live longer, less disrupted lives.
But as Covid has suddenly made self-testing mainstream, there is also huge opportunity for IVD tech to help everyone proactively manage their health. Self-screening for early signs of serious illness could transform healthcare and outcomes across the world. The opportunity and investment for research, invention and innovation in medical sensor tech has never been greater.
MEMS research and development is promising an age of ever smaller, more sophisticated and powerful devices.
But while specialists are developing cutting edge ideas for new and more powerful MEMS sensors, EMS providers are helping realise these complex designs into products that are more durable, effective and commercially viable.
As we break new territory in research and innovation it's going to herald a new era of co-operation between OEMs and EMS as inventions are productised, refined and further integrated into every aspect of our lives.