Hi Brent well done on considering diversifying and lowering your risk.
NPD is a tough one – how do you take a project far enough that you have certainty about the potential demand – but not so far you have committed money to something that isn’t going to fly? Some suggestions;
– share your concept – in writing including who will buy, why, features, benefits, cost, etc with as many people as you can – a trusted customer, friends you can trust for an honest answer, reach out to some one who works in an adjacent sector and ask for feedback.
– take that feedback and go further optomsie your product, ensuring you can follow through to commercialization (actually make it for the right price!)and then do a low resolution prototype if that is possible. then put it in front of more potential customers.
By that stage you should have some robust feedback that will help you work out whether more time and investment in the project is likely to pay off.
Good luck! Vicky