The decubitus, also known as pressure ulcer, is a wound that occurs due to pressure mainly on the protruding bones due to the patient is lying in bed on long time. This research purpose is to help prevent decubitus sores for immobility patients who are more bedridden during treatment at the hospital. This research module is a special mattress with an automatic pump which is equipped with an air pressure monitoring system on the mattress. The MPX5700 sensor measures mattress pressure. On the module testing, it can be observing that the largest error value on the low setting value measurement that is 2.25 % while the smallest error value on high setting measurement that is 1.84 %. Based on the results of tests and supported by the research, it can be concluded that the decubitus pump module can run well because it is still at the error tolerance threshold at ± 5 %.