Hardware Pt. 2
7As we return to our Digital BP machine, recall that the pressure transducer part is what usually “interprets” the heart rate. It takes the pressure differential between the atmosphere and the cuff to emit a voltage that is amplified by the DC amplifier. According to ChatPDF, after the signal is amplified, it is then filtered by something called a band pass filter. After the band pass filter, the AC component is taken to determine the systolic and diastolic blood pressures and the DC component is used as a reference point to determine the midpoint of the AC waveform. Finally, the signal reaches the MCU to be converted by the ADC from analog to digital, where it is then processed by the LCD to be shown on the screen as the systolic over the diastolic blood pressure.
This is a picture of the BP machine that I use for reference. There are some of the more obvious parts labeled such as the LCD and MCU that were mentioned previously. One thing that was not mentioned in the article by Cornell (that was also used in Blog #5 for analysis) was the solenoid valve. The purpose of the solenoid valve is to distribute the air into the cuff. According to ChatPDF, the air is distributed by an arbitrary motor in their BP machine, which is controlled by the MCU. To confirm whether or not ChatPDF was accurate, I looked over the article and the they indeed did not mention a specific solenoid valve that was used to distribute air. Whether it is because the article didn’t choose to focus on that specific part or they did not use a solenoid valve to pump the air, we can conclude that there was no LLM hallucination.
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On the other side of the MCU is the ADC. One thing that I had more trouble finding was the pressure transducer. According to ChatPDF, it isn’t supposed to be on the MCU, so I am guessing that it is located somewhere near the solenoid valve and the Oken Rolling Pump and stemming off from the “T.” Most of the parts are relatively similar although my machine may be a few generations older.
Considering the research that was done, if we are to create a product that connects the hardware to some kind of software, the point where we could take the information of the BP machine seems to be right before the ADC converter since after the band pass filter is where the signal is most fitting to be used. If we take the signal right after the transducer takes the differential, the signal would be too weak. But taken right after the DC amplifier, the signal will be too clouded, so the signal will be best right after the band pass filter. Also, ADC converters exist on every computer, so they could directly go from the machine to the computer.
Another issue, however, would be using bluetooth to connect the signal to the computer. Or, some sort of cable can be used to connect the two.
