A set of classical multi-wire proportional chambers was designed and constructed with the main
purpose of efficient cosmic muon detection. These detectors are relatively simple to construct, and
at the same time are low cost, making them ideal for educational purposes. The detector layers have
efficiencies above 99% for minimum ionizing cosmic muons, and their position resolution is about 1
cm, that is, particle trajectories are clearly observable. Visualization of straight tracks is
possible using an LED array, with the discriminated and latched signal driving the display. Due to
the exceptional operating stability of the chambers, the design can also be used for cosmic muon
telescopes.