Pressure Sensors, FSRs, and the Future
Force Is with You
Force sensors, FSRs, resistive sensors, and other pressure sensors are all around us…you just need to know where to look. These helpful little devices appear in technology used in a wide range of fields, including consumer tech, medical, automotive, industrial, and many more. For example, our resistive touchpads are used inmilitary laptops because the underlying force-based technology fares much better than traditional touchpads in the dirty, wet, dusty, and inclement environments—including those that are extremely hot or cold—in which servicemen and servicewomen are often expected to operate.Unlike traditional touchpads that require a bare finger to operate, our models only require pressure from touch, meaning they can even be manipulated while the user is wearing gloves.
A large supplier of medical devices employs force sensors on its radiotherapy machines during cancer treatments. In order to most effectively target the malignant tissue, the head of the radiotherapy device can rotate around the patient. This is an amazing feature, but presents a potential hazard while in motion. To prevent the machine from striking anything or anyone while it is in use, the applicator that extends from the head is fitted with force sensors that will immediately shut down the machine and alert the operator if it makes contact with the patient or anything else.
In the automotive industry, a pair of major automobile manufacturers has incorporated custom force sensors into their automobiles in two very distinct roles. In one application, they were used for extending a car’s door handle, which was designed to remain retracted and flush with the door panel when not in use. A built-in force sensor would detect the user’s touch and pop out the handle for them to open. Another manufacturer employed a custom FSR solution that replaced the mechanical buttons of its dashboard controls with a seamless touch-sensitive surface.
Living like the Jetsons?
The examples outlined above reflect just a small fraction of the many applications for force sensors. And the segment continues to expand thanks in significant part to the growth of the Internet of Things (Iota), which has introduced a whole new set of possible applications for a wide range of sensor types, including FSRs and other electronic force sensors. An electronic force sensor is a device that senses pressure exerted upon and generates a corresponding electric signal.
To get an idea of how the adoption of force sensing technology into more and more devices will impact your work and personal life, imagine this scenario: You end your shift and take off your work boots, which have safety force sensors in them to detect if a worker has fallen down or otherwise become incapacitated. Your car drives you home and easily finds a parking spot on the street via an app that uses pressure sensors to track empty spaces. After entering your connected home, you pull up a recipe on the display of the smart refrigerator, and the appliance automatically informs the oven what meal it will be cooking and preheats it to the required temperature while you pick and prepare the raw ingredients. As the meal is cooking, the oven sends a commandto set the table to a serving robot that employs pressure sensors to ensure it applies enough pressure to firmly grip its load without damaging any plates or glasses.
After being reminded to take your nightly medication via an app—which will know if you have already consumed a dose thanks to a pressure sensor on the cap that monitors when and how many times it has been opened—you can read yourself to sleep, letting the force sensors in your bed turn off the lights after you have entered REM sleep and been laying still for a certain length of time. And you’ll rest with additional peace of mind since, in addition to the break-in and optical sensors that protect your smart home, force sensing resistors in the floor can detect any unwanted visitors moving around and alert you.
While this may sound like a sci-fi fantasy, the force-sensing technology underlying many of these applications is already available. Combined with the expansion of the Iota, designers will have more opportunities to use FSRs and pressures sensors to make our lives more efficient and productivethan ever before.