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Blood Pressure Hardware DEsign

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hi everybdoy,

Anyone can give me some ideas on how to create blood pressure hardware with PIC.
Do I need to buy a cuff or is there any other way of measuring blood pressure with some kind of finger print pressure component?
Can someone show me some websites/circuit diagrams/codes which is related to blood pressure project with the use of PIC. Pls give me some advises and solutions. I would be much appreciated.


thanks!
 

chuckey

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See P.4 of the second link. Blood pressure is measured by listening to the blood flow and noting the pressure at which the flow stops and then releasing the pressure and listening for the flow to start again. So you need a cuff and controllable air pumps. . . The electronics is the easy bit.
Frank
 

jpanhalt

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@chuckey, That is not quite how it is done usually. The most common method is to inflate the cuff until all flow stops, then deflate it slowly until the first pulse sounds are heard. That is the systolic pressure. Finally, the cuff is deflated further until the pulse sound disappears. That is the diastolic pressure. One can estimate one or both measures during inflation, but that is not standard procedure in the US and can give different results. Let me add that in fact, most people experienced in taking blood pressure can get a reasonable estimate (e.g., normal, high, very high, or low) of systolic pressure just by feeling the pulse at the wrist. High diastolic pressure can also be estimated that way too.

@signup, A cuff is by far the most common method of non-invasively measuring blood pressure. My question is whether you just want to measure blood pressure or do you want to do the research needed to try to invent a method that doesn't use a cuff? If it is the former, use a cuff.

If it is the latter, you could look at ways to apply a controlled pressure to various pulse points (e.g., the wrist or ankle). Then correlate that pressure for the appearance and disappearance of a pulse with simultaneous, conventional blood pressure measurements. For example, with a little pressure, you can see the blood pulsing in a fingernail bed. The appearance and disappearance of the pulsations would be your indicator -- or use IR to detect beginning and ending of pulsatile of blood flow

Here is a lead I found on a non-cuff instrument that might give you some other ideas:

Take Blood Pressure Without Cuff

A new invention that has come up which helps to take blood pressure without cuff is the finger blood pressure monitor. The finger monitor is the latest technology that helps measure the blood pressure almost instantly in the most non-invasive way possible. This is a tiny digital device that works on batteries and consists of an electric monitor and a blood pressure sensor. There is a small finger compartment where the index finger of the person needs to be placed. Within a matter of seconds, the sensor reads the blood pressure in the finger and gives you the reading. This device is small and portable and hence, is preferred for regular monitoring of blood pressure in individuals, especially when the person is constantly on the go.
John
 

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See P.4 of the second link. Blood pressure is measured by listening to the blood flow and noting the pressure at which the flow stops and then releasing the pressure and listening for the flow to start again. So you need a cuff and controllable air pumps. . . The electronics is the easy bit.
Frank
hi, i have seen P.4 of the second link, its good, but its abit complicated for me to build it because i dunno which component model to use, eg like air pump, sensor,air valve, etc.

do u think its possible for me to build my blood pressure device by just using (MPS-2000-006GR DIP Pressure Sensor) in the first link provided by @ckshivaram. however, i got no idea on how to design it. im thinking tat it's just connect with some resistor and then connect the output to the PIC and analys the pressure in PC. i really need some help in designing this device.

i would prefer the 1st link because it looks simple and measure blood pressure with touching i guess. And 2nd also good, but its look complication for me.

my knowledge is limited, tats why i need a detail schematic diagram which indicate and guide me in buiding this device.

thanks!:grin:

---------- Post added at 09:25 ---------- Previous post was at 08:58 ----------

@chuckey, That is not quite how it is done usually. The most common method is to inflate the cuff until all flow stops, then deflate it slowly until the first pulse sounds are heard. That is the systolic pressure. Finally, the cuff is deflated further until the pulse sound disappears. That is the diastolic pressure. One can estimate one or both measures during inflation, but that is not standard procedure in the US and can give different results. Let me add that in fact, most people experienced in taking blood pressure can get a reasonable estimate (e.g., normal, high, very high, or low) of systolic pressure just by feeling the pulse at the wrist. High diastolic pressure can also be estimated that way too.

@signup, A cuff is by far the most common method of non-invasively measuring blood pressure. My question is whether you just want to measure blood pressure or do you want to do the research needed to try to invent a method that doesn't use a cuff? If it is the former, use a cuff.

If it is the latter, you could look at ways to apply a controlled pressure to various pulse points (e.g., the wrist or ankle). Then correlate that pressure for the appearance and disappearance of a pulse with simultaneous, conventional blood pressure measurements. For example, with a little pressure, you can see the blood pulsing in a fingernail bed. The appearance and disappearance of the pulsations would be your indicator -- or use IR to detect beginning and ending of pulsatile of blood flow

Here is a lead I found on a non-cuff instrument that might give you some other ideas:



John


@chuckey, That is not quite how it is done usually. The most common method is to inflate the cuff until all flow stops, then deflate it slowly until the first pulse sounds are heard. That is the systolic pressure. Finally, the cuff is deflated further until the pulse sound disappears. That is the diastolic pressure. One can estimate one or both measures during inflation, but that is not standard procedure in the US and can give different results. Let me add that in fact, most people experienced in taking blood pressure can get a reasonable estimate (e.g., normal, high, very high, or low) of systolic pressure just by feeling the pulse at the wrist. High diastolic pressure can also be estimated that way too.

@signup, A cuff is by far the most common method of non-invasively measuring blood pressure. My question is whether you just want to measure blood pressure or do you want to do the research needed to try to invent a method that doesn't use a cuff? If it is the former, use a cuff.

If it is the latter, you could look at ways to apply a controlled pressure to various pulse points (e.g., the wrist or ankle). Then correlate that pressure for the appearance and disappearance of a pulse with simultaneous, conventional blood pressure measurements. For example, with a little pressure, you can see the blood pulsing in a fingernail bed. The appearance and disappearance of the pulsations would be your indicator -- or use IR to detect beginning and ending of pulsatile of blood flow

Here is a lead I found on a non-cuff instrument that might give you some other ideas:



John


Hello jpanhalt,

My answer is, actually i just want to take blood pressure reading/signal and connect it to PIC, then connect it PC, after PC receives the signal/data, my program will interpret whether im underpressure/normal/highpressure. If its highpressure, my program will display im highpressure and my health condition is bad....


my problem is, i dont know which method is easier for me to construct
(index finger reading blood pressure? OR by implemeting the cuff method?)

the purpose i do research about finger blood pressure is because i guess it would be much easy to contruct compared to cuff method.
actually, it doesnt matter for me by using which method, i need a full guide and detail of the circuit design and if possible with program of PIC.


i need some schematic diagram which clearly drawn with details and component model used.

thanks! :)
 

BradtheRad

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Great idea to do as a project.

It will require obtaining special transducers.

I've used all kinds of blood pressure devices -- only just the kind that use a cuff.

The older types used the large cuff that goes around the arm.
Newer types have a small cuff that goes around the finger.

The cuff is a tough rubber balloon. One end narrows to a tube, which is attached to an air pump.

The balloon must be strong enough to hold a high degree of pressure that will reduce blood circulation just beneath the skin. The balloon must be contained in a compartment that will confine its size. The compartment must be just large enough for the finger to fit. (Arm cuffs are adjustable.)

An air pump pressurizes the balloon. The pump can be a squeeze bulb powered by a human. The electronic kind has a motorized pump.

The cuff must be pumped up to over 150 if the person has normal blood pressure. Or over 250, etc., for people with higher blood pressure.

Then a pinhole valve is opened to release air slowly. Old models had a needle valve opened by human fingers.

I don't know how it's done in all-electronic models. It may be sufficient to let air leak back slowly through the pump.

From now on you must keep the arm quiet and motionless.

The pressure can be read by eyes on an old-fashioned scale.

Or else to measure pressure electronically will require a special transducer. It must translate air pressure into electrical resistance or voltage or current. This may require effort to find.

The pressure transducer can be in direct contact with the air in the balloon. This is the easiest way to obtain calibrated readings with every use. However it will be hard to construct homemade.

Of course if the transducer is tiny and flat in shape, then it is easier to install it between the balloon and the surrounding compartment. The balloon in turn presses tight against the skin. This construction will be easier, however it will be hard if not impossible to maintain calibration at each use.

The other transducer needed will be audio. Listening for heartbeats. An electret microphone may be suitable if you amplify it enough.
 

jpanhalt

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Sound is used when a person takes blood pressure using a cuff and a stethoscope, but if you watch the pressure readings from the cuff, you will see that they start to pulsate during the systolic part and cease pulsating at the diastolic pressure. In fact, with the old mercury manometers, a patient could easily read the approximate BP at the same time as the operator just by watching pulsations in the mercury column.

So, to keep it simple, all the OP (sign up) needs to do is develop a device to apply variable pressure (i.e., a cuff) and monitor pulsations of that pressure as it is slowly released. That's a pressure transducer, a PIC, and an electronically controllable cuff. I suspect the OP is also looking for a finished project. A quick search will find several examples.

John
 

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