Coming to Our Senses: The Future of Sensors
Human progress depends on the ability to measure.
For millennia, our five senses were all we had to interpret and respond to the world around us. The story of civilization is the story of developing and using technology to extend the limits of our natural capabilities. We created ways to measure time – first sundials, then sophisticated devices like the sky disc of Nebra and the Antikythera mechanism – so we could better control our use of it. We mapped the night sky on the walls of the Lascaux caves and drew the first map of the world to determine where we were and where we wanted to go. And from the early telescopes and microscopes of the 16th and 17th centuries to the Hubble Space Telescope and the CERN particle collider, we’ve created increasingly sophisticated tools that let us interpret our world far beyond what our five senses permit on their own.
These tools now include digital sensors that will soon be ubiquitous. They’re so small that they’ll be completely integrated into the world around, on, and inside of us. These tiny sensors are already allowing us to understand the world we know more easily and precisely. But more intriguingly, they also enable us to measure things that were never measurable before.
Tiny and mighty
Early sensors were essentially just highly sophisticated monitors. They could be installed in places too small or dangerous for humans in order to measure common metrics like motion and acceleration, pressure, light, heat, and levels of chemicals and radioactivity. Still, their relatively large size and hunger for power limited their usefulness.
Today’s sensors require far less space and energy. As sensors get ever smaller, we’re likely to see microscopic “smart dust” that will alert farmers when their fields are dry, monitor engine performance from inside the fuel line, or determine whether someone’s neurons are firing properly after a stroke. Scientists have created sensor-laden pills that can transmit data about ulcers, cancer, and other gastrointestinal conditions for up to a month and then pass safely out of the body.
The use of sensors will extend long past quantifying and monitoring aspects of our physical health. In fact, they will augment the human body. We’ll have implantable sensors that measure and transmit muscle signals for more precise control of robotic prostheses; stretchy, transparent sensors that can feel and respond to complex sensations like skin does; and wearable sensors that can monitor medication levels and electrolyte levels in a person’s sweat in real time. And this technology will do more than just let us restore or enhance human abilities. It could let us give human abilities to technology, such as by letting soft robots safely handle fragile objects like glass or food by gauging how delicate their grip should be.
Exploring where no human has gone before
Smaller, more durable sensors will grant us access to previously unexplored realms, like the bottom of the sea. Scientists at Princeton University are trying to understand and predict seismic activity with a network of floating sensors that measure the buoyancy, viscosity, temperature, and density of the ocean floor and the kilometers of molten rock beneath it.
Similarly, MIT researchers are developing a network of battery-free, interconnected sensors that can drift through the ocean, transmitting data through acoustic waves, while a research team at a Saudi university is actually attaching flexible, non-toxic, silicon-based sensors directly to fish. These systems will track marine life and measure ocean dynamics like currents, water temperature, and pH levels in ecosystems humans have yet to explore, supporting long-term studies that might help us monitor and mitigate climate change.
Further afield, researchers at the National Institute of Standards and Technology have built a camera out of sensors capable of counting individual particles of light. Although the camera itself can’t go into deep space, it can spot and measure the absorption spectra of a star’s light as it passes through the atmosphere of one of its exoplanets. Scientists can then use that data to determine what elements are in the planet’s atmosphere and whether it might be able to support life.
Taking new measurements of the world
In addition to measuring things we previously couldn’t quantify, tomorrow’s sensors will let us measure things we previously didn’t consider quantifying or that we couldn’t conceive of as quantifiable. We might choose to hear at a spectrum as low as an elephant’s or as high as a dolphin’s, or adjust our vision to see ultraviolet, infrared, and other spectra whenever we want.
With sensors so minuscule that 30,000 of them fit on a penny and so powerful that they can record individual nerve signals, we could refine our other senses as well. You may never have considered the possibilities of measuring and quantifying taste, at least not beyond the famous Scoville unit that measures the heat of a hot pepper. But researchers have. Hypertaste is an AI-assisted digital tongue that can identify complex liquids quickly by using sensors that respond to different combinations of molecules to develop “fingerprints” (or would that be “tongueprints”?) of specific liquids and comparing them to a database of known liquids.
Electronic noses aren’t as far along in development, maybe because scent can be as emotional as it is objective. But researchers are also exploring how to engineer sensor arrays that can be tuned to distinguish specific odors, from the fruity breath characteristic of diabetics to the chemical compounds suggesting a sewage leak.
Consider the potential use cases for sensor-driven senses. They could deliver early warnings for environmental disasters, detect contaminated water, and track food freshness throughout the supply chain. A shopping AI might even draw on data from warehouse sensors to evaluate a particular product against quality checks and a customer’s known preferences: Has this milk gone bad? Is this sweater too warm or itchy? Is this air freshener pleasantly fragrant, or will it instantly trigger the customer’s allergies?
We’ll see you in our dreams
Some scientists are even working on sensors that will let us improve our lives while we sleep. Pajamas that can sense the wearer’s heartbeat, breathing, and sleep posture will be a boon for everyone, from people with sleep apnea to elderly residents of long-term care facilities, alerting them and their caretakers when they need to wake up, roll over, or call for emergency care.
And while the movie Inception remains a masterpiece of science fiction, sensors will bring us a bit closer to its world of altered dreams. MIT’s Dream Lab is working on open-source wearables that can detect what stage of sleep you’re in based on your muscle tone, heart rate, and skin conductance, and then change what you’re dreaming about by playing a prerecorded audio cue or emitting a scent at the moment you’re most receptive to it. You could enhance a new habit by hearing the word exercise, break yourself out of a nightmare with a whiff of a favorite food, or use the scent of a loved one’s perfume to help yourself heal from trauma and PTSD.
If you can measure something – capture it, record it, and quantify it – you can act on it. And with ever-tinier, increasingly capable sensors that assess almost anything, we’ll gain new insights and abilities to transform our minds, bodies, and the planet.