Types

Sensors can range from nano– to micro–size devices that can be implanted on or even inside the subject (human or non-human) all the way to regional scale sensors such as those installed in satellites. For example, there are many types of in-situ sensors currently available in the market, including most common following ones:

• Acceleration sensors: These sensors measure acceleration of objects, and motion that provides useful information in industrial applications to monitor machines or tools. One example is a sensor that protects a laptop from damage when it falls. https://www.youtube.com/watch?v=QH1iNwPXWic
• Force sensors: These sensors measure pressure and are often used to measure weight (to monitor loads on cranes or in grain silos, for example). Force sensors are used, for example, in IoT applications in medical and industrial instruments, packaging, and industrial machinery. https://www.youtube.com/watch?v=EKlaOMEfiUU
• Flow sensors: Flow sensors are used to measure the flow rate of liquids in various applications, typically vehicles, buildings, and factories. One example is measurement of flows in vented pipelines like drains or sewers to confirm whether they are at capacity. https://www.hackster.io/rhammell/river-monitoring-with-an-iot-flow-meter-9af852capacity
• Sound sensors: Sound sensors are primarily used to measure the noise level and the intensity of sound in different settings, such as cities or factories/restaurants. https://www.youtube.com/watch?v=IW3li3N4038
• Vibration sensors: Vibration sensors are used to sense vibrations of city infrastructure, factory machinery, power generators, and in vehicles. One example is the measurement of changes in vibration in factory machinery to predict maintenance requirements. https://www.youtube.com/watch?v=QH1iNwPXWic
• Humidity sensors: Humidity is an important environmental parameter and humidity sensors are frequently used in climate-based IoT applications and for air quality measurement in urban areas.
• Temperature sensors:Temperature sensors, used to measure the temperature of outdoor and indoor environments, are the most common sensors used in IoT applications. One example is the measurement of heat to monitor the operation of machines and devices in industrial systems.
• Gas sensors: Gas sensors are used to measure gases such as CO, CO2, and NO2 for pollution monitoring and CH4, H2S, and NH3 for emissions in the environment. They can be used for both indoor and outdoor environmental monitoring purposes. https://www.youtube.com/watch?v=qQPMeGbuoWg
• Chemical sensors: TThese sensors measure hazard levels of certain chemical compounds and radiations in the environment, mainly in harsh environments (for example, mining, chemical factories).
• Motion sensors: These sensors measure motion and rotation, which are important components in the automation industry. A very common example is a motion-sensing light that turns on when it detects motion in a room (if somebody walks in, for instance).
• Magnetic sensors: These sensors measure magnetic fields, which can be used in various industrial environments. Common applications include power steering, security, and current measurements on transmission lines.
• Light sensors: These sensors measure light strength for both energy management and environmental control applications. A common application of such sensors is to detect brightness in indoor settings and adjust the screen brightness of LCD monitors for optimum display.
• Pressure sensors:A pressure sensor measures pressure. A common example is seat occupancy monitoring in cars.
• Medical sensors: Small medical sensors such as ECG and heart rate monitors are designed to enable remote monitoring for IoT health care applications. https://www.youtube.com/watch?v=MiMDOT-Wt4w

Disruptive Power

By being constantly on and providing a continuous stream of real– or near realtime data, sensors disrupt traditional observation systems. By combining sensors with services, more responsive systems can be developed for commercial, humanitarian or environmental uses. For example, cell phones can “sense” and report their locations using global positioning systems (GPS), and businesses can use that information in location-based services to deliver more services. Retailers are experimenting with radio frequency identification (RFID) sensors and other solutions to track the location of customers within stores so they can target promotions and gauge response to merchandising initiatives. The healthcare industry seeks to improve and extend care and reduce cost through remote patient monitoring. The automotive industry is embedding sensors in vehicles and insurance companies are creating usage-based insurance models based on that sensor data. Utilities are deploying smart meters to identify usage trends for things like water and electricity, and helping consumers reduce their utility costs by consuming these commodities during low-demand periods. McKinsey Global Institute reports that more than 30 million networked sensors are in use in the transportation, automotive, industrial, utilities, and retail sectors, and the number is growing by 30 percent annually.

Potential for Development

Sensor-based delivery systems for plant nutrition can make agriculture more productive and responsive to local conditions. Local-scale sensors form the basis for smart-cities—canopies of PV leaves that generate enough power for local lighting, traffic lights that adjust to traffic volumes reducing idling, pollution monitors that indicate problem spots, drains that phone the public work department when they get clogged, cars that sense potholes and phone the roads dept. with location and depth of the hole, parking meters and spaces that signal availability to a parking map app, windows that become darker like sunglasses when the sun is shining really bright, conductive paint that can embed circuits in the wall, even crowdsourced mapping of stagnant pools of water that are malaria breeding grounds, and so on.

Caveats

The regional-scale sensors such as airborne or satellites will continue to be important, but they are too far away from the humans to provide local detail. Implanted or worn sensors, or even smart-home devices, provide great local detail, but are so fraught with privacy issues that getting that data into a single, global pool is possibly a fool’s errand unless we change the conversation around privacy and sharing. A sweet spot for large-scale sensors use is possible with large geographic scale, short temporal cycles, non-personally identifiable, public health, group behavior as shown below. "Local" sensors, on the other hand, have a better chance to not just scale, but also change the way we collect data about ourselves and our local environments with high temporal and spatial resolutions. By not collecting individual info, we sidestep the issues of privacy and security. These "local" sensors occupy a sweet spot providing useful local detail without getting tied up in privacy issues. Additionally, we can power them however we want, and we already know their position because they are static, so there is no need for battery-consumptive GPS.

Resources

Smart sensors will detect environmental pollution at the speed of light. https://www.youtube.com/watch?v=8NiVUzKFlzI

Real-time Air Quality Monitoring Network Using Low-Cost Devices. https://www.youtube.com/watch?v=82Cw7gi6hF0

Water Quality Sensors. https://www.youtube.com/watch?v=F1DK3IhyZao

Research: Novel Sensors.https://distap.mit.edu/research-novel-sensors/"

Water Quality Sensors. https://www.youtube.com/watch?v=F1DK3IhyZao

Research: Novel Sensors. https://distap.mit.edu/research-novel-sensors/