7.1.1 Discuss a range of control systems.

Control System	General Description	Sensor & Sensor's Role	Microprocessor's Role	Improvements Over Past or Alternative Systems & Possibilities for the Future
Automatic Doors	General Description Basically, the whole process boils down to the optic/motion sensor. The sensors are mounted over and integrated with the door slides. The sensors use either infrared or microwave technology to observe motion. As the sensors detect the motion, then the door can be opened. The optical or motion sensor is wired to an electrified main drive train that controls a clutch mechanism which opens up the door. Also modern cars doors......	Sensor & Sensor's Role To report to the microprocessor whenever an object that is likely a person is within the set range of the sensor. These sensors are pretty dumb: there is something there or not. But they may require a certain size to trigger them, so a mouse, for example would not.	-------- Automatic Doors -------- Microprocessor's Role To determine the various states (particularly person approaching or no person approaching), and send signals to open and close the doors accordingly. Determination of whether to keep opening, or start closing (for example in the middle of a close operation, start opening again if an arm is still there.)	Alternatively, a weight sensor can be used to trigger the opening of the doors; a person standing in front of the door, then it would sense the change in weight, and the door would open.  The use of a weight sensor has an advantages of having a clearer measurement and has a less advanced level of technological sophistication and thus potential repair. With motion/optical sensors,even a change in air flow could potentially trigger the opening of the doors. The use of weight sensor has clear disadvantage too. The area of detection is not as flexible as the one by motion detector, which can simply increase or decrease the detective range by putting less or more micro/infrared waves. Furthermore, the motion detector is much more durable, as the sensors are not the ones which receive the influence of the pressure directly. Other alterntives (present or future) include: Voice activation, laser (like Libor's dumb gate), motions like with Kinect, retina scanner, camera, the proximity of a key or card (as seen with modern cars' keys which unlock the car as the owner approaches).
Heating Systems	General Description A sensor keeps track of the temperature and adjusts the level of heating accordingly. Or in the case of a centralized control system, sensors throughout the building send data back - but the adjustments are done from the centralized server/processor.	Sensor & Sensor's Role The sensor senses the temperaturein the room and reports it, continually to the microprocessor. In terms of physically how this is sensed: thermo-couples can sense changes in temperature to very small degrees. Or, more conventionally, the sensor has something that expands and contracts with change in temparature.	-------- Heating Systems -------- Microprocessor's Role When the temperature reading in the room rises above a certain level, the heating unit is either turned down or turned off, and when the temperature reading falls below a certain level, the heating is turned up or turned on.	Improvements / Alternatives / Future An interesting thing is to note that a digital sensor is actually not as sensitive as an analog one. But a microprocessor allows a lot more flexibility in how the temperature is regulated. For example, the user can make a schedule which sets varying target temperatures - warmer during the day and cooler during the night. An improvment could be adding the control possibilities to the sensor itself. A "smart" sensor unit.
Taxi Meters	General Description A sensor is attached to the cab and every time the cab travels a certain distance, this sensor sends electric pulses to the meter. There is a timer in the meter that sends out a pulse whenever a certain amount of time has passed. When in slow, or stop-and-go traffic, the meter will use a combination of distance and time data according to a certain algorithm.	Sensor & Sensor's Role One sensor passes the data necessary for distance calculations, and one sensor passes data about wait time to the microprocessor. Distance is measured through the rotation of the wheels, so the sensor senses each rotation of the tire by proxmity of a magnet, or laser with a time delay mechanism. (So note, "speed" per se is not measured, rather it is calculated with the distance and time values.)	-------- Taxi Meters -------- Microprocessor's Role The microprocessor takes in the various inputs, both distance and wait time inputs and other selections made by the driver (like midnight to dawn extra charge, or bridge toll), and continually calculates and displays the fare on the meter.	Improvements / Alternatives / Future What are alternative ways of sensing input? A motion sensor could be used to see how much of the time is spent traveling and how much is spent waiting. The amount of gas used by the car could be measured so fares accurately represent how much gas costs for the trip. The current system of measuring distance and time works quite well. Motion could also be measured, and the fare could be increased when the taxi moves a certain amount; the wait time when motionless would have to continue to be measured.
Elevators	General Description Elevators are raised and lowered through either hydraulic presses or a system of ropes/pullies and counter-weights.	Sensor & Sensor's Role Technologies of the control system: Control mechanisms to say where you are going (buttons and then through electric signals to either the valve or the control system) Safety devices (phones, speakers, cameras will have various audio-visual sensors which relay to the microprocessor) Differnt access methods to certain floors via secure cards or keys. Weight sensors for overload. Door senses pressure if closing on someone.	-------- Elevators -------- Microprocessor's Role The microprocessor controls opening and closing of doors in various normal operations and safety situations. And the microprocessor may run sophisticated algorithms to determine the best up/down stop/start sequence during busy traffic times, and mayeven include data from other parallel elevators in the same building.	Improvements / Alternatives / Future "Smart" up/down stop/start algorithms will lead to much more efficient transport of passengers, particularly in multiple-elevator systems and during high traffic times.
Washing Machines	General Description The control system of washer usually resides in the control panel or the timer of the machine. The user usually inputs the temperature, length, and intensity of the washing-cycle and the timer/control board takes this information and run the cycle.	Sensor & Sensor's Role Temperature (thermometer) ⁃ this is the only way to measure temperature Water level (pressure switch) ⁃ this work by having the drum of the washing machine air tight, so that the air pressure inside the drum increases when water is added. Once the pressure reaches a specific point, the water valve is closed. "Spin-out-of-balance" (displacement sensor) ⁃ measures how much the drum moves when it spins. obviously the drum needs to move a little when there is an uneven load, but when the drum spins irregularly to a point where its displacement is greater than normal, the sensor gives of a warning message Plus: - drum speed sensor... - Water main failure (FloodStop) sensor... - Door closed sensor...	-------- Washing Machines -------- Microprocessor's Role The microprocessor has two functions: ⁃ 1) Taking in the values that the user gives and running a cycle with those values ⁃ i.e. running a cycle at 100º C, delicate, slow rotation... ⁃ 2) Making sure that all the sensor inputs (outlined above) are what they should be; if they aren't then the machine should report an error or try to fix it ⁃ i.e. if a cycle should be running at 100º but is at 90º, then the machine senses this and tries to correct it. Other functions of the microprocessor: - Control of heating the water to a specific temperature. - Control of spinning speed. - Monitoring weight, possibly via a simple Newton meter (a spring).	Improvements / Alternatives / Future Digital sensing of the various inputs can increase the efficiency of the wash and flexibility of the kinds of cycles which can be run. In older models, there were a limited number of standard cycles, which did not take into account real load weights, for example.
Process Control	General Description By this, any multi-step process could seen as process control, and so the situation of ensors on an assembly line at a factory controlling things.	Sensor & Sensor's Role Various sensors sensing various things. Think of a car assembly line, and things to be sensed such as where parts are, and when rivets have been successfully rivetted, and the temperature of various machinery and robots. Tons, and tons of things to be sensed, and controlled centrally, both for efficiency and safety reasons.	-------- Process Control -------- Microprocessor's Role To interpret all the various sensor input information, and send back control instructions to the various machines/robots based on that data.	Improvements / Alternatives / Future Increased autonomy handed over to the various machines or robots.
Device Drivers	General Description This probably means peripherals connected to a computer, say for example: a joystick or mouse.	Sensor & Sensor's Role Mouse Example - two types: Mouse optical sensor senses: acts like a dumb camera, and when it moves, communicates this to the computer. Mouse ball sensor - moving ball rotates the horizonal and veritical rollers.	-------- Device Drivers -------- Microprocessor's Role Microprocessor is actually in the computer, but it takes in the data from the mouse via the sensor. The processing is done by the CPU in conjunction with the driver software In the mouse example, to interpret the signals given from the sensor, via working with the specific mouse (software) driver, and then pass on the desired cursor movemement etc. to the application being used.	Improvements / Alternatives / Future In the mouse example, solve the issue of optical mice disfunction on certain shiny surfaces.
Domestic Robots	General Description Automated roaming vacuum cleaners, such as the Roomba track around a floor according to a variety of algorithms, and when they bump into a wall or furniture, they change direction and keep on cleaning.	Sensor & Sensor's Role The main sensor is the touch sensor about the circumference of the machine; it's role is to feedback to the microprocessor when it has hit the wall, or some other obstacle.	-------- Domestic Robots -------- Microprocessor's Role The processor, in a simple machine, simply controls the time of the clean and determines when an obstacle has been struck, and which direction to then try going. In a potentially more sophisticated machine, one way or the other, information about the room to be cleaned is taken into consideration in the development of an ideal series of cleaning forays.	Improvements / Alternatives / Future There theoretically could be sensors to sense the "cleanliness" of the floor over which the robot currently is. This could be done through the sensing of physical particles being taken in, or through smell. Poor algorithms can result in both a waste of time and energy, and parts of a floor being missed - so work to improve cleaning algorithms.
GPS Systems	General Description http://www.youtube.com/watch?v=0n0T992ccik Do watch this, but recall it's all based on triangulation of the distances of three satelites from the ground position.	Sensor & Sensor's Role Ground Control Stations: Sensors continually receive location information from each satellite. The Satellites Themselves: Somehow they must precisely sense their position over the earth, to be reported to their microprocessors in case corrective positioning must be taken.	-------- GPS Systems -------- Microprocessor's Role Ground Control Stations: the microprocessors monitor various important processes going on in each satellite which maintain its stable orbit, and also potentially instruct corrective measures on board the satellite when errors or problems occur. The Satellites Themselves: the microprocessors control all of the activities of the satellite, including the important transmission of "beams" down to earth, where GPS units receive them.	Improvements / Alternatives / Future Many, many benefits to humans on earth, not just those driving on highways. New geo-positon-using apps are being developed every day, since the smart phones which use them move with their owner, and can therefore report back things such as the nearest pizza restaurant or police station.
Traffic Lights	General Description Inductive loops: A groove is cut on an asphalt road, electric circuits are placed and covered. Whenever cars pass on, those electric circuits sends signal to the traffic light connected to them that the traffic light can sensor how many cars are coming or waiting.  Detectors: Detectors mounted on poles beside roads sensor cars. This way is more efficient then inductive loops. It takes less money to install, and also able to send real-life photos as well that inductive loop cannot do.	Sensor & Sensor's Role The sensor reports back continually to the microprocessor when a vehicle is approaching (either through motion detection or weight detection).	-------- Traffic Lights -------- Microprocessor's Role The microprocessor takes in the sensed motion or weight signal, and initiates the change in the traffic light's color, either immediately, or upon consideration of traffic going the other way and/or the amount of time since the light last changed color. Other inputs can be taken into consideration, such as if a tram is coming one direction or another (in Prague, at least, trams trump cars in almost all traffic interchange situations; the way they are going will be a green light).	Improvements / Alternatives / Future Past: First way is called the fixed traffic lights, which does not require sensor systems at all that the traffic light rotates to green and red for certain time period. Future: Infrared: Cars emit infrared that are recognized by devices can communicate with traffic lights. However, the disadvantage. If this is not part of the original cal, then people have to buy devices.  Radio Frequency: Input would be radio wave. This could be used without extra installation such as infrared since most cars have radio function. However, the problem is that Radio waves are not always recognizable, especially when the car windows are covered with coating. Card sensor: Input would be information in cards such as barcode or QR code. Traffic lights sensor card within cars and analyze information. This could require less money than Inductive Loops method.

Input Device/Sensor Name	General Description	Example
Accelerometer		Rocket launched into space
Color Sensors		Barcode reader. QR codes
Current Sensors	Motherboards of computers - ust check voltage drop across a resistor, to calculate the current.
Digital Compass		Airplane (but need analogue backup)
Infrared Encoder/Decoder	(Explanations for the first 10 or so can be found at http://www.societyofrobots.com/sensors.shtml.)
Load & Torque Sensors	Formula 1	Formula 1 pit stop tire change uses digital tourque meters to screw on bolts exactly the right amount.
Mercury Tilt Switch	(more old school, and not necessarily with microcontroller and digital sensor - usually analogue.
Photo-resistor
IR Range-finding
Tactile Bumper Switch
Voice Recognition	Can only be done by digital sampling and processing. No such thing as an "open seseme" analogue device.
Various NXT/Tetrix Sensors:	Touch, Light, Color, Infrared, Sonar, Sound...
Pressure	For weather prediction - assume new digital systems are more - remember that analogue measurements will still be more accurate.
Height	Planes measure, and skydivers - using pressure, zeroing at the ground where will be the jump destination
Smells and all Chemicals
Speed via GPS and/or accelerometer
Weight
Force
Direction

 

 

Input Devices / Sensors in Smart Phones

Sensor	Uses
Light	to change brightness of screen in different viewing situations
Proximity	to adjust the volume and turn off your screen
Accelerometer	senses rotation and adjusts the orientation of the screen
Camera	can sense: amount of light, with this can process face recognition, focus, QR Code, finger prints
Location GPS	to give walking/driving directions, to show restaurants and other services in the vicinity, etc.
Touches sensed (Buttons)	to give input to the device
Sounds can be sensed	hands free talking, dictate
Heat sensor	will shut down applications when overheating

                                                                                                

"Familiar" Situation	Input (i.e. Sensor) Device Options	Advantages	Disadvantages
1. Inputting information to my computer	1. Trackpad	Can do many gestures, such as three finger drag etc. Is a great alternative to mouse to add variety to input methods, and so prevent repetitive stress injuries (RSIs).	Harder for older people to figure out.
	2. Mouse	Precise (depending on precision of particular mouse) Possibly ergonomic, fitting the shape of the user's hand.	If not wireless, the chord. If wireless possible poor connection or temporary loss of connection to computer. If not perfect ergonomic fit to user's hand, real RSI potential.
	Future: 3. Leap Motion Controller, 4.Mind reading	Leap: more body movement, and so more exercise to a degree. Good for big screens on the wall, for example. Great for presentations. Mind reading: prevent RSIs, less annoying office noise.	Leap: not very accurate at this point. If the computer can read our mind, who else can...
2. Traffic light control (example of Nebusice traffic light by the Nebusice School)	1. Motion sensor / camera (Traditional digital)	Cheaper Easier to install and maintain More accurate potentially. Important here is to appreciate the goal, which is to slow down on-coming traffic before the school, so all it has to do is sense cars going over a certain speed and turns red so that they slow down, and then it turns green.	Can (possibly) be tricked by blowing leaves or other interference.
	2. Weight pressure sensor (Traditional digital)	More reliable, since can only be one thing when a heavy vehicle is over the sensor; not tricked by other things. Arguably more aesthetic since hidden, and driver is possibly not made nervous by a camera looking at them.	Harder to maintain since would have to dig up the asphalt. Much more expensive to install, since not only the sensor, but the digging up and re-paving of the street.
	Future: 3. Google drive	Much more intelligent algorithms based on overall traffic flow of a city, not just the individual traffic light. Once perfected, will make driving so much more safe. link to Google video	At this point, prone to errors. Probably expensive and difficult to set up.
3. Automatic Sliding Doors at a School	Motion sensor	Cheap. Easy to install. Easier to fix/replace	Can be tricked by interference by wind, leaves, and so on.
	Weight sensor	More reliable and accurate than a motion sensor.	More expensive and physically invasive to install (need to damage and replace tiles). Hard to fix/replace Would it be activated by little kids?
	Video camera and security guard	Ability to control who enters and when.	Overkill for a school; expensive to have a full-time guard monitoring and working the entry system. Even late at night, when only rarely people need entry, a security guard would have to be responsible for operating it.
4. Video Game input	Wii	Fairly reliable compared to other present commercial options. USB reliability	The user is tethered to machine.
	Kinect	No wand needed, only body movements. Possibilities of more kinds of body movements without more wand devices needed.	Not so accurate.
	Play-station Move Motion	Same as Wii?	Same as Wii?
	USB joystick	Tried and true, mature technology.	Can't stand with it; need a table.
5. Domestic work (particularly cleaning the floor)	Roomba	Simple to maintain. Specialized to do that specific task. Easy to operate.	Inaccurate. A single task domestic robot.
	Asimo - voice control	Can do a lot more than just clean the floor. Don't have to move from the sofa.	Can misunderstand you ("No, no, I said take ***out*** the garbage...), and may have trouble with different accents.
	Future - Asimo 10 - mind control (And think of the stuff being done at Boston Dynamics with humanoid robots.)	Don'teven  have to open your mouth!	(Will be) much more prone to mis-interpretations.
6A. Security Access to School - Czech Republic	Thumb-scans.	Very hard to trick. Unquestionably cool.	Expensive technology. Maintenance of the system would be difficult and expensive.
	Smart Phone	Everyone always has their phone with them. It would have a "cool" factor that school's administration and Development Office would see as benefiting the image of the school.	Actually, everyone does not ***always*** have their phone with them.
	ID cards with magnetic strip	Easy to implement. Simple, mature technology. Could be combined with existing cafeteria payment cards.	Cards get lost. Cards could be easily stolen.
6B. Security Access to Google-plex - California	Thumb-scans.	Very hard to trick, and security in this case more of a priority. The unquestionably cool aspect fits in nicely with the image of the company. Google can afford it.	None really.
	Smart Phone	Everyone always has their phone with them.	Actually, everyone does not ***always*** have their phone with them.
	ID cards with magnetic strip	Simple, but no need to combine with cafeteria payment cards; food for worker of the Google-plex is free.	Easy to counterfeit and steal. So poor security compared to other options.