This is my design of small game trap, it use a rubber band (or bands) to pull a snare.
It is preferable to connect the front and rare part using a wooden rode (taken from a wooden cloths hanger with size of 9.5-9.8 mm diameter)
however, if you don't have a wooden hanger, you can download the STL tube file and use pins to connect the tubes together
you need to glue the parts together and use a cotton string for the snare.
it is simple, I hope you like it, The .dwg file is available if someone want to modify the design (Autocad format)