Someday, the hardware police are going to come and take away my toys, citing me for criminal abuse. Until then, I'll continue to see what an NXT can handle... and what I can learn in the process.
On a recent trip to Niagara Falls, I was fascinated again with this huge, impressive natural feature. And thinking about the foolhardy souls that over the years have tried to survive going over the falls in a barrel, I did what was natural for me - thought about the NXT doing it. Of course, getting permission to throw something over Niagara Falls is unlikely to happen... and it's dangerous, and retrieving it would be extremely difficult. But I could certainly do some test runs... so was born the "NXT in a barrel".
I used an NXT slid into a 4" PVC pipe segment, sealed tightly at either end with removable closeout plugs. To keep it from bouncing around inside, I used a hot-wire cutter to shape foam "bulkheads" to support and lock the NXT into place within the tube, and attached a 50' line to retrieve it after. Then I went to a small local dam, started it, sealed it tightly, took a deep breath... and threw it over.
The NXT logged two sensors 30 times a second, a 3-axis accelerometer from Mindsensors, and the LEGO sound sensor. Above the dam it floated tranquilly, quietly, and approached the edge. During the fall, the sound level went up only a little, but the accelerometer clearly registered a freefall as it went over the edge. Then there's a sharp acceleration as the pipe hits the rocky bottom end-on, and the noise level suddenly spikes up, as water crashes down on top of the PVC pipe and the unit is tossed and turned at the sloped, rocky base of the falls. Then suddenly it quiets down, bouncing in the tailrace in the fast-moving water below the waterfall.
All in all, this gave me yet another chance to "live vicariously" and understand something that I have no (safe) way of experiencing myself. Could I scale this up? Certainly (& I'm planning to, in a couple of different ways). Could this be used as a teaching tool? Absolutely, in so many ways. Total cost beyond the NXT was maybe $15 total for the plumbing, and programming was very easy.
Niagara Falls it's not... but it's as close as most of us are likely to get. Now excuse me, I've got to find a bigger waterfall...