Status Review:
* Alex joined us as a recent graduate of the UofM with a specialty in signal processing and firmware.
* Germaine: Started checking the new versions of the Sphygmochron. The new features, some of the numbers are not right and still get error message. Chris sent a question on public health usage scenarios. Franz and Germaine produced an abstract for Chris to review. After Chris adds his comments, it will be posted. So, she has open activities with Larry and Chris.
* Mary Jo: Running into constraints with the lab. Got a new oscilloscope, fried her board, the voltage generator doesn't produce a low enough signal to test, went online to determine how, Agilent Model DSO 3062A, S/N CN4503894, Software version is 3.01.28, and a firmware update USB A to B.
* Bob Schlentz: Omron makes home blood pressure monitors. Earlier this year, one of the journals had an author who took apart one of the Omron home monitors and discovered: 1) Cost at Walgreens was about $40, 2) it didn't do many of the functions we are addressing, 3) the one-at-at time costs were: $20 for motor, valves, tubing and cuff), the electronics was around $20. The cuff tubing plugs directly into the board, the chamber changes capacitance with the pressure. The chamber provides a capacitance for a ring oscillator to a sine wave, and the processor counts the pulses per second, and that gets around the need for an analog to digital converter. This leads to: it doesn't do what is needed for this project. If we use something other than a blood pressure cuff we would need another input. I thought we would need an 8 bit A-D converter. Actually, we need a 1000 bits because we need calibration from FDA and a resolution of 1 mm of mercury pressure. If we use something else, we need the same equipment resolution, range of 0 to 300 mm of mercury. Going further, with a typical transducer we can count on a 5% of full-scale variation for the complete range off the device. Now, when we look at the DC output of the piezo system as opposed to the AC, we would have a steady pressure with one value for the piezo resistor and another value when it was very low. When we look at the values from a changing value, we get the results that were published on the web (under piezo film sensor). So, we need more resolution. For a sensor that we put it on the body, we now have a new FDA requirement. For the duration of time, it should have no irritation with the skin. Notice that the cuffs are usually used with a cover, which must be compatible with the skin.
Issues:
* Bob: Noticed: 1) HIPAA law suites over insurance firms getting too much information from clinicians. 2) RoHS - without lead in solder, you get inter-metallic growths that produce junctions between the two copper surfaces breaking the connection, and this can occur in 120 days, even just sitting on a shelf. Even silver solder has tin, lead and silver.
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