Feedback and Control Systems

We have come to wonderful time where a lot of things have become automatic and this is due to beautiful feedback and control system.

One example of a feedback and control system we encounter frequently are automatic doors. Automatic doors are able to sense that a person is in front of it either through a weight sensor usually disguised as a black mat in front of it or through optic or motion sensors that sense motion in front of it. The computational part of this system converts the digital reading from the sensors in to a command to make the doors open which is the actuation mechanism of this system. Sometimes the sensing mechanism of this system becomes a little rusty and it does not sense that someone is in front of the doors causing many people, including myself, to stand and wave around awkwardly in front of the door until it opens. The actuation mechanism of this system is pretty great. It's pretty handy to have the doors automatically open especially when your hands are full. 

Another example of a real-world feedback and control system are the ones we encounter in a public bathroom. In a lot of bathrooms, there are now automatic hand dryers, soap dispensers, faucets, and toilets. These systems sense when there is something a certain distance away from it. The computational part then converts this information to turn the hand dryer on, the soap dispenser dispense a certain amount of soap, turn on the faucet for a few seconds, and flush the toilets. The actuation mechanism of these systems are amazing since they provide sanitation to its users. The sensing mechanism of these systems are sometimes lacking though. Sometimes automatic toilets flush before people stand up, faucet sensors are too high up, and automatic hand dryers don't turn on.

Another really cool example of a feedback and control system is the water station that we have in a few buildings here in Wellesley. The sensing mechanism senses when there is something underneath it and a second or two later the actuation mechanism dispenses water and when the bottle is removed from under the sensor the actuation mechanism immediately stops the water from continuing to flow out. One thing that works poorly in this system is the time it takes for the information from the sensor to be converted to the command that makes the water stop flowing out. But overall this system is pretty great since it can get tiring pressing down on the button of the water dispenser until your whole bottle is filled and losing a few milliliters of water is not too bad.

An oven is another example of a feedback and control system. You turn on an oven and set it to a certain temperature. An oven's sensor senses the temperature of the inside of the oven. When the oven reaches the temperature you wanted it to be, heat stops being released. If the oven is still on and the temperature begins to dip, the computational part of the system sends information to the actuation part to start releasing heat again until the oven reaches the temperature you programmed it to be again. This cycle continues until you turn off the oven or if the timer you place on it goes off. A really cool part of this system is that its output is also sensed and used to create another different output. 

What ovens usually prevent us from having to do.