To develop this project I learned that it's necessary to verify and analyze each step to follow, eg:

• Pressure measurements of this device were compared with an aneroid manometer.
• I had to calibrate the air release valve several times.
• This model can be useful for a doctor or nurse who suffers from a bad hearing, because it would be imposible to detect the Korotkoff sounds.
• In the final tests I feel satisfied with the values measured by my device when I compare it with the OMRON device.