The airsoft land mine I bought was a pitiful waste of $50. The self proclaimed "loud boom followed by a large blast of powder" was a tiny pop and half inch high puff. Enemies didn't even notice that they triggered it. This is the prototype version of my trip mine. It throws BBs about twenty-eight feet and baking soda about five. It is spring powered and acts like a piston; the spring is attached (by a washer and screw) to a plug. To operate, place the spring mechanism inside the pipe. Push it down with a plunger and lock the plug in place with the pin. As soon as I finish the final version I will post an Instructable.
http://www.instructables.com/id/Build-an-Airsoft-Trip-Mine/
when i tried to make something like this it would be too hard to pull the string and my target (best friend) didnt set it off, saw it, and came running after me with a 2x4.
the second time it was easy to set off, but the spring wasnt powerful enough to make the bbs go far enough.
my refined mine, is near perfect. but it took alot of thinking to get it.
im thinking about posting an instructable.
ttyl.
*!* tell me how this thing works. im interested *!*