QTC's magnetic attraction

Have been prototyping ideas for a client using Quantum Tunelling Compound (QTC) and SuperMagnets. Sounds very high tech but effectively its using the 'pull' of these super powerful magnets to squeeze some QTC to make electricity flow through a circuit. This means the QTC is being used as a pressure switch.
Even better is that QTC is cheap, about 35p (UK) for enough to work in my light bracelet, with the magnets costing about 40p.
I have agreed with the client to develop projects where the total cost of components / materials is no more than about £1.40. This rules out most gearboxes, and anything complicated so I am left with basic materials to make unusual projects.

£1.40 a project works because if it is easy for students to make, and personalise then it is far more likely they will bring in money to buy it, while if it costs £4, usually a state school will recycle the materials if possible. So investing £50 ina class project, confident of getting most of it back if taught well is better than having stuff left over every time.

It may seem odd to spend hundreds of pounds paying someone to develop a project that cost less than two quid (£2 UK), but cheap projects don't mean cheap thinking, usually it means full price cogitation to make something that we can all afford to use in class, and therefore develop both the teachers and the students skills in one affordable stroke!