Tips & Tricks: These topics are very important from the ICT exam point of view.
Which are the measurement or measuring applications?
These types of applications involve use of various types of sensors and other hardware like microprocessors. The sensors that are used generally take light intention, rate of rotation, temperature, etc. As the data is usually in analogue form, they are sent to an Analogue to Digital Converter (ADC) to turn the data into digital format. This conversion is necessary as microprocessors and computers only understand digital data.
The term analogue means the data varies constantly and has no discrete values. For example, the height of mercury in a thermometer to represent temperature.
The term digital refers to discrete data which is made up of binary values 0 and 1. However, when you to need control devices like pumps, heaters, valves, etc., the data or signals (i.e. a series of 1s and 0s) from the computer needs to be converted back to an analogue form (e.g. electric signals) using a Digital to Analogue Converter (DAC).
After conversion of the data, the data is sent to microprocessor where it is processed. However, in measuring applications, microprocessors are programmed to only review the data from the sensors (often comparing it to the data which is stored in memory) and update their files and sometimes giving a warning signal if the values are outside the given parameters. The microprocessor do not take any action to change any of the data or conditions during the measurement process.
Common examples of measuring applications are:
- measuring a patient’s vital signs in a hospital
- monitoring of pollution
- weather stations
- burglar alarm systems
- scientific experiments (e.g., taking light intensity).
Weather stations are generally setup to automatically gather data from the environment. They are mostly unmanned and use a variety of sensors to measure:
- wind speed
- barometric pressure (air pressure)
- wind direction
The data is gathered 24 / 7 (i.e. 24 hours a day, 7 days a week). This data is then used by weather forecasters to help predict the weather for the next few days or even take a more long term view by looking at past and current weather patterns.
Measuring a patient’s vital signs in a hospital
Using a computer to measure the key vital signs of a patient in a hospital, can be seen in the following steps:
- sensors read key vital signs such as heart rate, temperature, blood pressure, respiration, pulse rate, etc
- the data from the sensors are converted into digital format using an Analogue to Digital Converter (ADC)
- the data is stored in the computer’s memory
- the computer compares the data from the sensors with the values stored in its memory (these are usually fed in advance either by the nurse or doctor for a given patient)
- the results are displayed on a screen in the form of graphs and/or numerical readouts
- an alarm is activated if any of the data is outside acceptable input values
- the system continues to measure the patient’s vital signs until the computer is switched off.
Measuring Pollution in a river
The below steps show how a computer can be used to measure pollution in a river:
- the sensors are placed in atleast two different positions to do a pollution comparison at various points
- the data from the sensors are converted into digital form using an ADC and sent to a computer
- the computer stores the data received
- the acidity levels and oxygen levels are compared with the historical data stored in computer databases and they are also compared with preset levels stored in the databases.
- the oxygen and acidity levels from the different positions in the river are also compared to see if they are similar. This sometimes help to find the source of pollution.
The data stored in the computer can now be transferred either by copying this to a CD/DVD/USB media and taken away for further processing and analysis or the computer can connected to a LAN/WAN network or internet and transmit the data back automatically to the monitoring station.
Other types of sensors such as light sensors (to check whether there are solids or chemicals in the water blocking out light) or temperature sensors (to check the temperature of water at different points which might disturb the marine life in the river), can also be used.
Advantages of using a computer for measurement applications
- The computer’s response time is very fast (which is very important in the hospital monitoring system).
- The computer does not forget to take readings.
- Scientists, Doctors, nurses, etc., can carry on with other tasks whilst the measurements are being taken automatically and precisely.
- The readings are generally more accurate than when taken manually.
- There is a huge cost saving the in the long run, as lesser staff are needed since the measurements are now being done by computer (which in turn reduced wage bill).
- It could also be safer to use sensors since whatever is being measured may have potential hazards (e.g., Chemicals in the river which might result in skin rashes, etc or a nurse being infected with an infectious disease while continuously looking after a patient).
- Computers can be programmed to produce graphs automatically for faster analysis of results.
- Computers can measure data 24 hours X 7 days without tiring out.
- Due to this the readings can be taken more frequently using sensors and computers.
Disadvantages of using a computer for measurement applications
- If the computer malfunctions or if there are frequent power cuts, then a computer cannot be used. Due to this, there should be proper backup procedures in place to over this eventuality.
- The computer cannot respond to unusual circumstances.
- A student doing an experiment using a computer for measurement and analysis, may not learn as much using a computer system.
- The initial cost to setup the measuring software and computer is usually very high.
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