I like it   But when I saw your concept, I immediately thought about retired people.  They have time to kill,  need exercise,  and it's a fun/exciting activity!  Treasure hunting, hell yeah!  A scarey close parallel would be those metal detector treasure hunters.  Although with this,  you don't need to spend 1000 dollars on equipment.  I think retired people are a great potential demographic for this project.  Remember,  as the years go by,  the percentage of older people who are comfortable with electronics will steadily increase.  Just a thought.  I'm glad you can take constructive criticism with a smile, I'm rooting for you guys!

PS  I was a little concerned that you demonstrated in the video walking while looking at the phone,  might be a potential liability issue,  I dunno.  You can go on Liveleak and watch videos of people who walked into ponds because they were looking at their phones and drowned.

I'm not trying to be a dick. It's easy for me to point out the failures of the man in the ring. Just trying to help.

“It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again, because there is no effort without error and shortcoming; but who does actually strive to do the deeds; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of high achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid souls who neither know victory nor defeat.”  -Theodore Roosevelt