Goal: In this blog post we’re asked to identify feedback and control systems in the real world.
Sound activated lights:
Sound activated lights are lights that turn on whenever it senses sound waves. Usually, all sound activated devices have a small microphone to detect sound waves. There are two different uses that I am somewhat familiar with. The first one is the sound activated lights in the staircases when I lived in China. I remember stomping my feet to get the lights to turn on. The other use that I read online was lights that change patterns according to music. Sound activation is used in many aspects of our lives and I would imagine it being used even more widely now that we are able to program computers to understand spoken commands.
Motion-sensing alarms:
The motion-sensing alarm uses motion sensors that detect infrared light. Infrared light is emitted by human and other animals. Even though people can’t see infrared light, infrared detectors are made to detect light in the infrared range. I have attached a link below of an episode of Mythbusters on thermal motion sensors.
Pressure sensors:
Pressure sensors can be found almost anywhere nowadays. There is one in every car to detect the pressure in the tires, there are pressure sensors in the kitchen. But pressure sensors are also used for industrial application in quality control. Or what people might be more excited about, the iphone screen. The pressure sensor uses pressure sensitive material as a force collector. Then uses that information to compute the pressure in the given environment. Link attached below for more information about different types of force collectors.
https://en.wikipedia.org/wiki/Pressure_sensor
Oh, the sound-activated lights reminded me of something we talked about in PHYS 216! We were learning about Fourier transforms (expressing an equation as the sum of sine and cosine equations), and we watched this one video where someone linked a guitar to a bunch of LEDs, and translated the frequency the guitar played to the wavelength of the LEDs. He then showed it to a deaf friend so she could visualize music.