[blparent] does this exist?

[Star Gazer]

Hi folks, 
Steve's comments about the light probe got me thinking. 
Is there a device that would beep or vibrate when you point it toward the
floor? Speciffically, I want to have a better way of cleaning up food my
baby tosses. Cleaning up the food isn't the problem, finding it is. 
I was thinking that if a device existed that would beep or vibrate when it
picked up something other then flat floor, that would be wonderful! Could I
be that lucky?