Have you thought about approaching friends/family for financial backing to get the idea going? Especially to help you test create the thing? So many things look good on paper but end up being impractical for other reasons once it is built...
or else, looking into other methods to finance the creation of a prototype?
It is always easier to get others to invest in something if you can show your thing working...
In the end, you have to tell somebody or noone will be able to buy it
