The Desktop Muon Detector: A simple, physics-motivated machine- and   electronics-shop project for university students
  This paper describes an undergraduate-level physics project that incorporates various aspects of machine- and electronics-shop technical development. The desktop muon detector is a self-contained apparatus that employs plastic scintillator as a detection medium and a silicon photomultiplier for light collection. These detectors can be used in conjunction with the provided software to make interesting physics measurements. The total cost of each counter is approximately $100. 
Spencer N. Axani, Janet M. Conrad, Conor Kirby
physics.ed-ph