Trip mines

Last Sunday, I was lying in a ditch waiting for the enemy to come. I was watching our teams flank and I was there to hold up any enemy attack trying to flank our team. While I was waiting there I was thinking to myself, wouldn't it be useful to have a trip mine down the way they would come come if they were to attack.

Since then I have been thinking alot about how to get a trip mine. However I am not sure on how to go about it. There are several things I have to consider:
» one is that I dont have the budget to go out and buy an airsoft claymore or mine. That means it will have to be cheap so it will probably be a DIY job.
» two is that the sites I play at dont allow grenades or mines to be filled with BBs so it needs to be something that makes a loud noise.
»three is that it needs to be small enough to be easy enough to carry.

Hoping to hear your thoughts and ideas. Is the requirements too much to ask for or is it possible.

Happy posting.