Input, Output, and Sensors Flashcards

Question

Digital Camera: Images

Answer 1

Controlled by the microprocessor, which automatically adjusts shutter speed, focus, flash, etc. Light passes through the lens onto a light sensitive cell made of pixels. +: Images can be viewed immediately and can be edited easily on a computer. -: Poor lens quality, limited memory for photo storage.

Answer 2

Quick Response code: Consists of a square black and white pattern, representing binary. It is captured by a camera/scanner that breaks it down into a grid. Processed light is reflected. Black reflects less than white Squares are decoded. +: Holds a lot of data, doesn’t need a connected database, can store a variety of info (URL, payments) -: Not suitable for info that changes regularly, needs a device/software that can read it.

Answer 3

A laser is shone at barcode; light is reflected to see if black or white. Reflected light is read by sensor, pattern is converted into digital. Used in categorizing and retrieval of store products. Used in airports to track luggage. +: Accurate and precise, reduces pricing error, improved customer service. -: Possible misreads, barcodes need to be printed on labels and tags.

Answer 4

Documents are placed on the glass. Scan head moves across so image can be sent to a lens. Lens deconstructs light. CCD produces electrical charges. Digital image is produced by software. Used to create 2D images. Used to read passports. +: Very accurate, high quality, large variety, higher resolution compared to digital camera. -: Uses a lot of computer’s storage, can lose some of its quality.

Answer 5

Scans objects using lasers to measure dimensions (h,w,l). Laser detects details about shape and converts it into digital data. +: Can scan tough surfaces, high resolution, and accuracy, less sensitive to changing light. -: Shiny/transparent surfaces do not work.

Answer 6

Allows users to write on the surface using a pen. Text and drawings are then captured electronically and stored for later use. +: Easy to use, can access files to display. -: Expensive to install and maintain.

Answer 7

specific type of input device used to gather information about physical environment

Answer 8

- motion/infrared - pressure - light - pH - gas - humidity - sound

Answer 9

Sensor sends data readings to the microprocessor at set intervals. To be understood, this data might need to be converted using an ADC (analogue to digital converter). The microprocessor compares data readings against pre-set values it has stores (using a control program). The microprocessor then makes a decision as to whether any action is needed. If needed, the microprocessor will send a signal to instruct an output device to do something. This may involve an actuator. This process repeats in a continuous loop.

Answer 10

An acoustic sensor detects sound. This might include sound that is too low-pitched, too high-pitched or too quiet for humans to hear. One application of an acoustic sensor would be a burglar alarm, which could be used to detect a break-in.

Answer 11

An accelerometer measures acceleration force (the rate of change of velocity). They are often used in smart phones to detect movement (for example, when a game is controlled by moving the phone itself).

Answer 12

Flow sensors measure the flow speed of liquids or gases in pipes. This is important in many situations. For example, a reduced flow speed in a pipe might mean there is a leak or a blockage in the pipe, and a flow sensor can be used to detect this situation.

Answer 13

Gas sensors can detect the presence of different gases. This is essential in many safety systems. For example, a gas sensor may be used to detect the presence of toxic gases in a chemical manufacturing plant.

Answer 14

A humidity sensor detects water vapour in the air. Humidity sensors can be used in air conditioning or environmental control systems. For example, a greenhouse might use a humidity sensor to help a computer determine if the environment is correct for the plants growing there.

Answer 15

An infra-red (IR) sensor is a type of light sensor that detects invisible infra-red light. Infra-red sensors are often used to measure the presence of objects. For example, an automatic door system might use an infra-red sensor to detect a person walking in front of the door.

Answer 16

A level sensor uses a gyroscope to measure angular movement. This enables the sensor to detect if it is being tilted or rotated. A common application for these sensors is in smart phones, which can be controlled by tilting or waving the device.

Answer 17

Light sensors detect light levels. This light could be visible light or invisible light, such as infra-red. Light sensors can be used in automatic lighting systems to switch on lights when natural light levels fall below a certain level.

Answer 18

A magnetic field sensor measures the strength of a magnetic field. They are sometimes used in geophysical surveys.

Answer 19

A moisture sensors measures the presence of water.

Answer 20

A pH sensor detects how acidic or alkaline a substance is. pH sensors might be used in swimming pools or aquariums to check the pH of the water, or in a chemical factory to help ensure the pH level is correct.

Answer 21

A pressure sensor may refer to two different types of sensor: A sensor which measures the pressure of a liquid or gas, such as in a pipe. A sensor which means the weight pushing down on it, such as a floor plate which can detect the pressure of a person standing on it.

Answer 22

A proximity sensor can detect when an object is close, even if the objects are not touching. They are used in many situations where collisions need to be avoided. For example, many cars have proximity sensors to warn the driver when an object is very close to the front or rear of the car.

Answer 23

Temperature sensors measure heat energy. Many home appliances such as microwaves, kettles and washing machines contain temperature sensors. This helps ensure they are working correctly and safely.