The thing is, the prototype will have to be robust enough for it to convince. Because the actual use of the device will be tested in real condition. So I cannot

The thing is, the prototype will have to be robust enough for it to convince. Because the actual use of the device will be tested in real condition. So I cannot make an ugly prototype with wires all over the place. I need a "near final" form factor and battery use. I will look into your suggestions.