COMPUTER CONTROL

Year 11

Lesson 1

Introduction to Computer Control

Starter

Computer Control?

Write down as many things as you can to do with computer control

Uses of computer control

List down uses of computer control in your booklet

COMPUTER CONTROL

Computer control is where a computer controls a device in order to make something happen

In order to do this it must have some data to process. Data can be collected by sensors and relayed to the computer automatically.

The information that the sensors give back will allow the computer to make a decision about what to do next

INPUT – PROCESS - OUTPUT There are three stages of a control system are:

INPUT – PROCESS – OUTPUT

Input – the means of getting information into the computer

Process – instructions for the computer to do something with the input

Output – it then has to be able to alter something in the outside world

FEEDBACK

Feedback is essential for any computer-controlled system

Feedback is where sensors continually send signals back to the computer to let it know what it is doing

This is useful when a certain set of conditions needs to be constantly maintained

FEEDBACK

For example, a robot needs to navigate around a maze.

A touch sensor is used to let the robot know it has hit a wall.

This feedback may then tell the control process to reverse the robot and change direction.

The process is repeated many times.

INPUT PROCESS OUTPUT

FEEDBACK

Task

In groups you will look at a specific work place and research its use of computer control.

In your booklet you will need to design a storyboard to show the main pieces of information you have found out.

• Hospital

• Car Factory

• Theme Park

• Cinema

Plenary: How good is computer control?

Why do you think it took me 2 hours to get out of a car park?

Advantages of Computer Control Computers can operate 24 hours a day without a

break

Identical tasks can be easily repeated

Very accurate

Data is processed quickly, response can be rapid

Can be used in dangerous places

Can consider hundreds of inputs at one time

Usually inexpensive to run – no wages to pay

Disadvantages of Computer Control

Adding a computer to a control system is expensive

To run properly needs software – more expensive

Sensors and actuators makes the system more complicated – less reliable than a simple human operated system

Only as good as the control software – if anything unexpected happens, a person is much more flexible

Review of learning

What were the aims of the lesson?

What did you achieve?

What have you learned?

Lesson 2

Flow Charts

Flowcharts These are often the easiest way to visually show processes in a

computer systemSymbol Meaning

Start/End The terminator symbol marks the starting or ending point of the

process. It usually contains the word "Start" or "End."

Action or ProcessA box can represent a single step ("add two cups of flour"), or an entire

sub-process ("make bread") within a larger process.

DecisionA decision or branching point. Lines representing different decisions

emerge from different points of the diamond.

Input/OutputRepresents material or information entering or leaving the process,

such as customer order (input) or a product (output).

FlowchartsSymbol Meaning

Flow LineLines indicate the sequence of steps and the direction of flow.

Data storageIndicates a step where data gets stored. For Example "Save Orders"

DelayIndicates a delay in the process. For example "Wait 1 day"

Sub-RoutineAn independent program segment separate from the main program

that performs a specific task

Advantages and Disadvantages of Flowcharts

Advantages Disadvantages

Flowcharts are good way to communicate the details of a process to all concerned. Flowcharts can help people analyse problems or bottlenecks in a process Flowcharts are an excellent way of documenting a process In software development, flowcharts act as a guide or blueprint for the programmer. Flowcharts enable an organisation to have a record of standard business processes.

Some processes or programs are so complex that it becomes difficult to represent them clearly in a flowchart. If an alteration needs to be made to the system, the flow chart usually needs to be redrawn. If it is a complicated flowchart, this can require a lot of work. People need to understand what the flowchart means and what the different symbols represent. You cannot give a flowchart to a complete novice and expect them to understand it.

ACTUATORS

An Actuator is a device to which can convert an electrical control signal to a physical action.

For example, in a greenhouse, the data from the sensors tell the computer that the temperature is too hot. The computer sends a signal to the actuator which causes the motor to open the window.

Task

Using Flowol you are going to create a flowchart for the barriers on the car park

Task

Start (get on) End (get off)

Drop (splash down)

ramp

boat waiting area

Then move onto the theme park ride

Plenary

Print screen one of your finish flow charts into your booklet and annotation it to explain how it works

Review of learning

What were the aims of the lesson?

What did you achieve?

What have you learnt?

Lesson 3

Data Logging Sensors

SENSORS

Sensors are used to detect and measure physical quantities such as:

•Temperature

•Pressure

•Sound

•Light

•Humidity

ANALOGUE & DIGITAL

Sensors can send two types of signal to a computer – digital and analogue

Digital signals can only have two values: on (or true) and off (or false)

Analogue signals can have any value

ANALOGUE & DIGITAL

A computer can only deal with digital signals, so to be able to process analogue signals sent to it by a sensor the computer needs an analogue-to-digital converter (ADC)

This device converts analogue signals, which computers can’t process directly, into equivalent digital signals which they can process

ANALOGUE SENSORS

LIGHT SENSORS Light sensors can detect how bright a light is They can be used to automatically turn a light

on when it gets dark and off when it gets light

HEAT SENSORS Heat sensors can detect and measure heat They can automatically turn a heater on for

example when the temperature is below a set value and off when it reaches a different value

ANALOGUE SENSORS

INFRA-RED SENSORS These are used to detect movement They can be used to turn on lights on your

drive when someone approaches your house, or detect movement as part of a burglar alarm

SOUND SENSORS Detect how loud sound is Could be used to detect how loud noise that

comes from a building is, for example

ANALOGUE SENSORS

TOUCH SENSORS Can be used to detect if an object is

touching something For example, if an automatic hoover

touches the wall

HUMIDITY SENSORS Measures how much moisture there is in

the air or soil Used where it important to make sure that

the air or soil isn’t too dry or too wet

ANALOGUE SENSORS

PRESSURE SENSORS Are used to detect when there is a weight

on something They can be used to detect cars driving

down a road or the depth of rivers