Physical Computing

Physical

Computing

What is physical computing?

Sensing and control and data logging.

Examples are everywhere:

• pelican crossing
• thermostat
• wash cycle
• burglar alarm
• robotics
• sensing and data collection

Why should you teach

physical computing?

The short answer is that this is an engaging and creative practical topic that children enjoy learning about. It is also an excellent context for the teaching of computational thinking and simple coding.

What does physical

computing look like?

In Primary schools, physical computing takes on a number of guises. It can be modelled, virtually, on a computer using Scratch, LOGO and even Flowol with a range of mimics. If a school cannot afford to set up some control workstations this is better than nothing at all.

Much better practice, and far more enjoyable for the children, is to teach the topic using physical models linked to a computer.

What does the

Computing POS say?

Early Years /

Foundation Stage

Through the use of programmable toys, such as the Roamer, BeeBot and the BigTrak, control can be introduced at EYFS.

These toys enable the children to develop an intuitive understanding of the need to decompose a problem and to build a logical sequence of instructions to solve it.

The toys also encourage children to think about position and space, and use the appropriate vocabulary.

Key Stage 1

At Key Stage 1 a simple interface, such as the Learn & Go, can be used to connect and control electrical components. The computer is built into the interface.

Lights, LEDs, buzzers and motors can be controlled via the four outputs.

Traffic lights

Traffic light control is a simple starting point for Key Stage 1.

Once an interface has been connected to the computer the children should be taught how to use the control software.

A site license for the control software is usually supplied with the interface hardware. If not, a site license for some generic control software such as, Flowol can be purchased so that the children can learn how to program on a standard workstation and only need to use an interface to test their programs with a model. Make sure that the generic software and interface are compatible.

For a set of traffic lights, tree outputs are used, one for each light. You can make the wires as long as you like.

If LEDs are used they may need a protecting resistor.

Key Stage 2

Lighthouse

The lighthouse is a very simple model to make. All the children need is a cardboard tube and a clear plastic cup. They will also need components, two lamps, a buzzer, an LDR and a push switch.

Fairground

A fairground ride is another model that the children could make as a DT project. The aim of this project is to introduce motor control. Each of the models that the children make should have at least one feature that is turned by an electric motor.

Level crossing

The level crossing project is a good example of the need for precision in automated systems where peoples' safety is concerned. It also requires the children to learn precise control using an electric motor.

Input 1 is triggered by the approaching train. The sensor could be a pressure pad or light gate of some sort. Input 1 will cause the lights to flash, alarm to sound and barrier to close as the train approaches. Input 2 will cause the barrier to open once the train has passed.

The outputs are the two red lights, an amber light and a buzzer for the alarm. The barrier is raised and lowered by an electric motor with a built in 200:1 gear box.

Automatic fan

This project will help the children to understand self-regulating control systems and the important concept of negative feedback. Negative feedback is common to a wide range of control systems from the ball cock in a toilet systern to the regulation of glucose in the blood stream to a central heating thermostat.

The children will be introduced to the thermistor for temperature sensing. The thermistor is an analogue component. Unlike a switch which is digital (ON or OFF) the thermistor gives a range of values depending on its temperature.

This project requires an interface with an analogue input and software that can accept numerical inputs from sensors such as the thermistor.

Line following

vehicle

The control program for the line following vehicle is a very simple one but children are amazed when they build a vehicle that is able to follow a black line drawn on a piece of card.

This is another example of negative feedback in a control system. The project works best if the program can be downloaded to the interface, running on batteries, so that the vehicle does not need to be connected to a computer.

A pair of LDRs are used to detect the black line. They must be positioned just above the line about a centimetre apart. The line is illuminated by an LED. The two LDRs could be replaced by a pair of microswitches for a touch sensitive vehicle.

Why should you teach physical computing?

The bullet points below provide a wider rationale:

• Physical computing is included in the Computing POS as an essential element of the subject.

• One of the most important developments in information technology in the next five to ten years will be the expanding ‘Internet of things’.

• The Internet of things is a world of physical objects that are seamlessly integrated into the information network, in which the physical objects become active participants in business, service and domestic processes.

• It is estimated that by 2020 there will be 50 billion devices connected to the internet.

• The United Kingdom will need large numbers of people with the skills to design, manufacture, install, service and manage these devices.

• If we are to be a global leader in this new technology we must make the most of the opportunities presented within the Computing POS to educate our children from an early age.

• Children should leave our Primary schools with an awareness that computers are involved in the control of a vast array of everyday devices as well as some very specific and highly technical applications.

Children need to know that Scratch is not the only programming language. As they are exposed to other languages they will come to understand that programming techniques are generic and transferable. The teaching of a control language is an excellent way of achieving this.

The final two projects are quite advanced for Primary schools. They could be tackled in after schools clubs or as a way of extending gifted children.