  A set of classical multi-wire proportional chambers were 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.
