As we invest in more mobile technology, we run the risk of bulging pockets and heavy handbags. This activity looks at finding a solution to this problem. In this session you can remind students about electrical circuits and resistance and explore the unusual properties of QTC. QTC (Quantum Tunnelling Composite)... ...could be just the solution we need as it offers the potential for technical textiles. What if we could have the latest gadgets integrated into our clothing? There are many ideas for all different types of technical textiles visit: www.engineeringuk. com/viewitem.cfm?cit_id=383661 for a mobile phone dress. What You Need ✓ General circuits equipment: including crocodile clips, leads, PSU (6v), buzzers, bulbs (the number depends on the size of your group) ✓ Some fabric (any fabric should be OK e.g. old clothes or cotton) and some foam e.g. a sponge that you can cut up ✓ A conducting material, such as aluminium foil ✓ Scissors and glue ✓ QTC pills (these are available at www.mutr.co.uk stock code QTC 001, but you may even have been sent some in the past in TEP or SEP sets) in partnership with This session should fill a club timeslot as a one off project (or it can be used as part of a short term project if extras are followed). The Right Switch Activity
Transcript
As we invest in more mobile technology, we run the risk of bulging pockets and heavy handbags. This activity looks at finding a solution to this problem.
In this session you can remind students about electrical circuits and
resistance and explore the unusual properties of QTC.
QTC (Quantum Tunnelling Composite)......could be just the solution we need as it offers the potential for technical textiles.
What if we could have the latest gadgets integrated into our clothing?
There are many ideas for all different types of technical textiles visit: www.engineeringuk.com/viewitem.cfm?cit_id=383661 for a mobile phone dress.
What You Need
✓ General circuits equipment: including
crocodile clips, leads, PSU (6v),
buzzers, bulbs (the number depends
on the size of your group)
✓ Some fabric (any fabric should be
OK e.g. old clothes or cotton) and
some foam e.g. a sponge that you
can cut up
✓ A conducting material, such as
aluminium foil
✓ Scissors and glue
✓ QTC pills (these are available at
www.mutr.co.uk stock code QTC
001, but you may even have been
sent some in the past in TEP or
SEP sets)
in partnership with
This session
should fill a club
timeslot as a one off
project (or it can be
used as part of a short
term project if extras
are followed).
The Right Switch
Activity
Some Extras... What else could QTC be used for? Ask your club to research ideas for QTC (www.peratech.com/qtcapplications.php is a good places to start).
Can they design, and even make a new product using this material? Think about how it could be used to improve home appliances.
Perhaps this could for the start of your bronze Crest Award? www.britishscienceassociation.org/crest
Can you make a multi-switch? Think about which types of circuit might be suitable.
ExplanationQTC (Quantum Tunnelling Composite) is a composite material.
A mixture of silicone and nickel, it exhibits both insulating and conducting properties, covering a resistance of a trillion ohms! The more pressure applied to QTC in a circuit, the more conductive it becomes.
Why does this happen? The nickel particles are shaped like a mace ball. At the end of the spike the tunneling electron gives
rise to these unusual electrical properties. More advance students may wish to research quantum mechanics!
Handy Hints A quick, easy way to demonstrate
QTC (without a circuit) is to use a flat watch battery and an LED. Place the
legs of the LED either side of the battery and the LED will light up.
Now put a QTC pill on one side of the battery (against a ‘leg’). The LED will not light up until the
QTC pill is squeezed.
The more pressure applied to the QTC, the more the LED should light up.
Cover this in card or plastic and you have a quick and easy pressure sensitive torch. (Idea thanks to
Famida Noor-Mahomed @ Little Illford School).
What To Do QTC can be used to make a textile switch. We are going to make a fabric switch to control the circuit in a jacket for a light or sound.
Before setting up the circuit make your switch.
Cut two pieces of fabric (the same size – they do not have to be big!) and stick a strip of conducting material down the centre of each piece. Cut a piece of foam with a hole in the middle for your pill and stick to one of the conducting strips (see picture, the depth of the foam should be no greater than 1 cm).
You do not want the two conducting pieces to touch, so you can make the foam extend the width of the conducting strip as long as there is room for your crocodile clips. Insert the pill into its foam pocket and stick the other conducting piece on top and you have your first textile switch.
Set up the circuit as shown in the picture (on the front page). Your switch can be attached to the circuit by attaching one crocodile clip to the top piece of fabric (be sure to attach to the conducting material) and one clip on the bottom piece of fabric of your switch (but the opposite end).
When you turn the circuit on, nothing should happen as the QTC acts like an insulator.
v When you press the switch (QTC), your circuit should work. Try pressing harder; what happens?
v If you have used a lamp in your circuit try and get it to half light. Does the light flicker?
This shows the QTC can act like a sensor as it responds to your body.
Curriculum Links Using this activity you could discuss:
England Science: Unit 7J: Electrical circuits,
Unit 9I: Energy and electricity
PSHE: looking at real-life situations, personal preferences and priorities.
D&T: Unit 08aii: Exploring materials focus: resistant materials, Unit 09bii: Designing for markets focus: resistant materials
Example of QTC sensor providing a sensing skin in a robotic or prosthetic hand.
An artist's-eye view of a particle of metal similar to the nickel used in QTC.
Who Uses QTC?
David Lussey
Peratech has since won several prestigious industry awards including the Saatchi and Saatchi Communication Award and the Tomorrow’s World Industry Award. Peratech has also been the recipient of three SMART awards from the UK Government to aid the development and exploitation of QTCs.
QTC materials have been used by organisations such as NASA, who have integrated the material into astronauts spacesuits. Instead of carrying equipment on spacewalks an astronaut can press a panel on their sleeve to work their remote controlled buggy or even the fans in their helmet. Back on earth the material is used in snowboarding jackets, where an IPod in the inside pocket can be controlled by a QTC panel on the sleeve.
There are numerous possible applications of QTC (as you can see at www.peratech.com/qtcapplications.php) and your group may well have thought of more!
v How important do your group think engineering and technology will be in the development of these products?
Special thanks to David Lussey and Peratech for the use of words and pictures, and the inspiration.
Page 3
Some MathsVoltage (V) can be found using:
V= IR, where I = current in amps and R = resistance in ohms.
Measure the voltage and current in your circuit when you are pressing your QTC switch (using a voltmeter and ammeter).
Rearrange the above equation and find R.
If you were able to reduce the resistance by 10% (and keep the voltage constant), what would the new current in the circuit be?
This Is EngineeringBeing creative and facing modern challenges such as understanding QTC and designing suitable applications is just one aspect of engineering.
Engineers with an interest in design look at creating the initial ideas and ‘blueprints’ for systems, structures and products, testing models rigorously to ensure they work, using computer aided design (CAD) to help.
There are several different degree courses available covering engineering and design requiring A-Levels, 14–19 Diplomas or Scottish Advanced Highers for entry (www.ucas.com)
Related fields: Materials science and electronic engineering.
Contact Us
The Royal Academy of Engineering 3 Carlton House TerraceLondon SW1Y 5DG Tel: 020 7766 0600 Fax: 020 7930 1549 Web: www.raeng.org.uk
