Looks pretty impressive, congrats.

Thanks folks

You should sell your design lol :)

Thanks Tyler.  Great find.  What is uint32_t?  I think I saw that in your prior code too, if I'm correct.  

uint32_t is a 32-bit unsigned integer data type as defined in the AVR version of inttypes.h (a common C/C++ library), part of the Arduino core:

• http://www.nongnu.org/avr-libc/user-manual/group__avr__inttypes.html
• http://www.atmel.com/webdoc/avrlibcreferencemanual/group__avr__inttypes.html

Both links describe the same thing, but one is by Atmel (Microchip, nowadays) and the other by AVR Libc. Not actually sure which one of them is responsible for it.

The common Arduino equivalent on the Arduino Uno is unsigned long. I like using inttypes.h because it explicitly sets the word length (32-bits, in this example), whereas the word length may change if using the Arduino language. An easy example is double: it's 4 bytes on Arduinos that use ATmega chips (e.g. Uno), but 8 bytes on those with 32-bit chips (e.g. Due).

Nice video Tyler.  Why did the graph peak for the whiteout object? And what software did you use to graph your chart?  Thanks very much.  

Each object is a different height and volume, so the echo time is different for each, which is what I was hoping. I used Excel to graph the data.