Abstract -- Large detectors like ALICE in CERN are often equipped with additional cosmic ray detectors. These detectors are used to obtain information about which tracks inside the detector came from the passage of a particle coming from an atmospheric cascade (eg: muons), and are not as a product of an internal collision. They are also very useful for calibrating detectors such as TOF or TPC. The nature of radiation changes in relation to the direction in the sky which we observe as well as the influence of very thick walls or ground. The goal of this exercise is to self build a small cosmic ray detector and making real measurements using it.