Interesting game plan: ask a totally nebulous question, including just enough information so that only someone who was already working with your target devices would know what you were talking about, and then use your second post to insult the very people you're seeking help from. Not sure what the thinking is behind that, but I hope it works out for you.
You could help people help you by:
A) Not assuming that everyone here, no matter how experienced, has worked with the device you're currently interested in;
B) Including a bit more information on the level of project you're looking for: i.e. are we talking grade 4, grade 11, second-year university, what?
C) Defining what "somewhat difficult" is. Can your students already make an ultrasonic rangefinder from scratch? Or can they just make LEDs blink, or make a line-following bot, or what? More information please!
Just some thoughts which might help you get some more useful responses.
Also, I just entered NTX into Google and got hundreds of thousands of hits. I'm almost certain that you could find the perfect project with 15 minutes of googling.
Torben