How To Detect a Gunshot
One point to note : patents stop you selling what you build (if it infringes on them). But they don't stop you building one to test. 

That's deliberate, because they are as much about communicating the patented technique as they are about protecting the inventor - to encourage the spread and growth of good ideas for public benefit. 

In theory. 

In practice, the "communication" aspect is encrypted in legal jargon and is usually written to satisfy the letter of the "communication" aspect without actually communicating anything. If an inventor can get the protection of a patent without breaking the trade secret behind it, he has a good patent attorney drafting the claims...

Nevertheless. you have the right to build any patented invention to test that the published idea works, as well as to improve on it if possible. You just can't sell (or hire or lease or give away or benefit from) the product without some agreement with the inventor, unless you are prepared to challenge the validity of the patent in court (not recommended!)

So legally I think you can use a patented technique for a school project (though I Am Not A Lawyer) - with proper attribution of course - as long as you are gaining no material benefit from it.

The school may consider winning a competition or passing a course is a "material benefit", or they may impose their own rules for the sake of the competition - it may be worth asking your tutor or adviser.