Control

Control is one of 4 subjects in the Technology 'circus' together with Resistant Materials, Textiles and Food. Students spend 9 weeks in each area with 2X50 minute periods per week.

Year 7

Specification

You will be making a Steady Hand Game. The base for it will be made from Acrylic. You will design the shape of this base and it must fulfill the following criteria:

• It must be stable - a steady hand game cannot be played if the wire is waving about.
• The battery and buzzer must be hidden from view.
• The whole unit must be pleasing to the eye. The shape of the base should say “I made that, and I’m proud of it”

Scheme of Work

1. Components of the circuit. Power Supply (battery), consumer (bulb), route (cable). Students to draw these parts and label them. Practical demonstration of these parts. Series and Parallel. Demonstration of effect of two bulbs in series and parallel. Students to draw Series and Parallel circuit in notebooks.
2. The led and resistor. Demonstrate polarity concious nature of led. Student to draw led and identify anode/cathode leads. Need for resistor. What is a resistor. The water pipe as an analogy. Student to solder led and resistor to cable together with crocodile clips and test. Check on polarity.
3. Introduce Steady Hand game as a switch circuit. Students to sketch pictorial view of the game. Design requirements of the acrylic housing. Students sketch ideas. Clean up plastic square, mark out and bend. Safety in Workshop and use of Strip Heater.
4. Mark out and drill holes in plastic. Safe use of the Bench drill. Bend wire and hot glue into place. Safe use of Hot Glue gun. Sketch circuit diagram.
5. Solder battery holder and buzzer into circuit. Fit insulation around upright. Test complete circuit. Student to evaluate design.
6. Investigation into types of switch. Rocker, Push, Key types examined. Circuits drawn in notebooks and description of various types, where they may be used.
7. Further types. The Float Switch. Students to be encouraged to suggest possible uses. Description and construction.
8. Membrane switch - make and test the operation. Notes and drawings to be made by students in their books. Evaluation of design and success.
9. Complete all notes and construction. End of module test.

Year 8

Brief

My aunt has a great number of pot-plants. She likes to keep them correctly watered - it’s bad for them to dry out. When my aunt is on holiday I have to look after the plants and I would like some kind of gadget to tell me when they need watering....

Specification

• Build a device that will indicate, by a green led, that the plant soil is moist enough.
• The device is to be held in one hand. Measure your hand and design the shape of the device so that it is comfortable to hold and operate.
• Test the device and describe any improvements you feel should be made

Scheme of Work

1. Re-cap on circuits and components learnt in First Year using Omega kits to produce series and parallel circuits. Control as Input-Process-Output. Simple examples of control, such as door opening and thermostat.
2. Introduction to the brief. Develop ideas of sensing moisture to use with indoor plants. Need for accurate water checks. Ergonomics of hand grip. Measurements of hand and design constaints - single handed operation, push switch and l.e.d. veiwing angle.
3. Workshop safety. Shaping and making hand grip, using files, rasps and coping saw. Drilling MDF and insertion of prods.
4. Vacuum forming cover. Safety rules required for using equipment. Demonstration, then students in threes to make cover. Continue hand shaping, spray paintiing with aerosols.
5. Introduction to Graphics. Demonstration of Two Point Perspective and use of colour. Students to produce two point perspective drawing of Moisture Sensor.
6. Use of Etch Tank to produce circuit board. Demonstration and safety points. Introduction resistor colour coding and identification.. Students to complete Worksheet 9 - Resistors.
7. The Transistor as a switch. Identification of Base, Collector and Emiter. Current flow through an NPN transistor. Soldering these components to the board.
8. The l.e.d. and why it needs protection. Soldering these components to the board.
9. Evaluation of design. End of module test.

For a very good introduction to Control take a look at this page at Leeds University

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