applied electronics electronic mini project 1 tcm4-117078

Electronics Mini-Project

Standard Grade Technological Studies: Applied Electronics – Electronics Mini-Project 155

Contents

Introduction 157Application of Technology 158Example: Remote Controlled Buggy with Light and Sound 159

Brief 159Specification 159System diagrams 159555 timer circuit 160Buzzer circuit 160

Computer simulation 161Prototype board layout 161Stripboard layout diagram 162Component list 162Connecting to the receiver 163Develop, build and test 164Evaluation 164

Appendix 1: Infrared Remote Control 165Support materials 165TEP remote control system 165Infrared remote controllers 166Modulated signals 166The controller 167The receiver 168

Remote controlled toy 169The brief 169Motor connections 170Latching 171

Standard Grade Technological Studies: Applied Electronics – Electronics Mini-Project156

Introduction

This project can be used to help students prepare for the Application of Technology assessment. It is an example of a possible mini-project that will stimulate students in their study of technology. It gives them an opportunity to explore further areas of technology that are not compulsory and to go beyond the specified content of the course.

This project should not be confused with the assignments that SQA will issue for the assessment of the Application of Technology element.

The project gives added value and interest to Standard Grade Technological Studies as well as being a suitable vehicle for preparation for assessment. This mini-project will allow students to engage in an interesting project that will cover the requirements of the internal assessment; that is, to: complete a specification from a given brief create appropriate diagrams to illustrate the problem parameters produce graphical representation of a proposed solution identify appropriate components from a pre-prepared list or from data sheets perform a computer simulation of the proposed solution build and test the proposed solution evaluate the solution against the original specification.

Students will be given a brief to extend or enhance a selected mini-project (in this case a remote-controlled buggy). This will become clearer when the initial part of this mini-project nears completion.


Application of Technology

Application of Technology is an assessment element of Standard Grade Technological Studies. It is included to reflect the requirement for students to apply knowledge, understanding and skills in a purposeful way in order to solve technological problems. Students are required to undertake two structured assignments for this internal assessment. The SQA will provide centres with a detailed structure for each assignment each year. It is envisaged that teachers will prepare their students for these tasks by teacher-led examples. This ‘mini-project’ is one such example.

This project uses the Technology Enhancement Programme (TEP) remote-control system. The transmitter is a hand-held type normally used to control televisions in the home. The receiver is a small circuit board that ‘thinks’ that it is a Sony television.


Transmitter Receiver

Example: Remote-Controlled Buggy with Light and Sound

Brief

Use or build a three-wheeled buggy that has sound and flashing light.

Specification

The buggy must move under control. The buggy must be steerable. LEDs fixed to the receiver must flash on and off. The LEDs must flash automatically once the signal is given from the transmitter. A warning buzzer must be attached to the buggy. The warning buzzer should be on the same circuit board as the LED circuit. Different channels must control the LED circuit and the buzzer.

System diagrams


555-timer circuit

This circuit includes alternate flashing LEDs and uses a 555-timer integrated circuit acting as an astable device.

Buzzer circuit

The buzzer can be added to the circuit board later. It will be connected straight to the receiver output.

The 0-volt line in both circuits will be connected to the negative terminal of the outputs on the receiver. The positive voltage in the circuits will be connected to the positive terminal.


Computer simulation

The circuit was tested using Crocodile Clips and it worked perfectly. The size of the input resistors (to pins 6 and 7) can be increased to decrease the frequency of the flashing.

If the supply voltage is reduced to three volts then the protective resistors for the LEDs can be decreased to 100 ohms.

Prototype board layout


Stripboard layout diagram

The component values can be taken from the circuit diagram.

Note: X marks where the track has to be cut on the track-side of the stripboard.

Component list

Item Quantity Value/typeStripboard 1 12 strips 25 holesResistor 2 270 Resistor 1 22 kResistor 1 1 kResistor 1 220

Integrated circuit (IC) 1 555 timerLight-emitting diode (LED) 1 5 mm

Capacitor 1 47 F (16 volt) electrolyticBuzzer 1 Miniature 6 V (max)


Connecting to the receiver

The connections would be made as follows.

Motor to channel A Motor to channel B 555-timer circuit to channel 1 Buzzer circuit to channel 2

The connections will be made through a connecting block to prevent damage to the receiver circuit board.


Develop, build and test

This section will test the physical circuit and its operation. Diagrams or graphics of the buggy layout would appear here. If the buggy were supplied in kit form then some graphics would be provided.

Students would be expected to keep notes on any problems encountered and on adjustments and improvements made to allow their circuits to operate effectively. Notes on reasons for failure would also be useful.

Evaluation

This section would put together logical notes on the operation of the project. Notes taken during the developing, building and testing would be extremely useful. The final circuit has to be evaluated to each of the specifications. This should be in depth for credit students. A photograph of the working solution would add to this evaluation.


applied electronics electronic mini project 1 tcm4-117078

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