4.7 Build prototype/demonstrator
The physical models we talked about earlier are prototypes or demonstrators of a sort. However, for the purposes of making a clear distinction in the process, I'm referring here to prototypes or demonstrators as functioning preliminary models of the essential finished product or construction or service, bringing together all the elements of the design that may or may not have been previously physically tested (Figure 18). This is still a model – if appropriate, it may be a full-sized, full-colour replica – but it may also be a scaled-down version where only the vital working parts are fully functioning.
In the village water supply problem, you may produce a model version of the layout of pipes to ensure that they will conform to the landscape, or you may not need to produce a demonstrator at all. The point is, where necessary, to make sure that all the essentials will come together and operate as anticipated.
In software design, for example, the prototype may be a program that combines all the essential elements of code, written by various teams and controlling various parts, but with a dummy user interface. The vital commands will be in place, but asides such as 'glossy' add-ons (for example the electronic games on a mobile phone) are not necessary to the success of the solution, and may be designed separately and added to the overall design at a later stage. Note that to do this, you have to be very sure that these extras will not affect any important aspect of the rest of the product. In a well-run project, you will have to prove to the rest of the team or the project leader that this is a valid assumption before being allowed to leave it off the demonstrator.
Put simply, with good planning and thorough preparation and groundwork the demonstrator should work when tested in the conditions in which it will be expected to perform.