Looking for docs about methods for heart beat monitoring

[zainka]

Heart beat monitoring

For a new product, one of its features will be to measure the heart beat rate. I know of a methode using red/IR-LED to light through your finger and then measure the change in intensity as blood pass by, but I cant find any good resource describing these methodes or others. Anyone knowing of anything??

Best regards
Vidar (Z)

 

[narccizzo]

Re: Heart beat monitoring

Do you need theory or practical info like schematics, etc.? because some time ago I did a HB monitor with plethysmography (IR light). And I can help you with some info.

Added after 25 minutes:

This is the prototype in action.

 

[zainka]

Re: Heart beat monitoring

Hi thanks for your reply.

Theory and Schematics would do fine and an short description of your schematics.
By the way, I thought plethysmography utilized ultrasound to measure both systolic and diastolic blood preasure and not the beat rate (puls) of hart?

Second by the way... You seem to be an relaxed person

Best regards
Vidar (Z)

 

[narccizzo]

Re: Heart beat monitoring

Hi,
Actually I am doing a non invasive continuous arterial pressure monitor not like 120/80, but as beat to beat (getting the pressure wave) as thesis project for my master grade, and that is right, plethysmography is used to measure the blood pressure but with IR light technique.
This is the scheme that I recommend you to get a good signal, the picture is not good looking because it was taken with mi cellphone, but it is quite simple. You can adjust the two potentiometers to put the signal between the 0-5v range for an ADC and to do the algorithm that detects every peak, or you can implement a window comparator with another op-amp or bjt transistor, this reduces software to only measure time between events.

Regards.

 

[artem]

Heart beat monitoring

check this one may be helpful

 

[narccizzo]

Heart beat monitoring

The IR led and IR phototransistor does not need to be from a specific type or wavelength. I am using a general purpose sensors.

 

[Jepeto]

Re: Heart beat monitoring

Hope this will help
Although they use RF tuning amplifier, from my experience this method has poor results and noise sensitivity, the better way is to use analog multiplier for Doppler detecting

 

[Nicholas]

Heart beat monitoring

I have been trying this also recently. My problem is that the photo-coupler consumes too much current as for the battery power.

 

[artem]

Re: Heart beat monitoring

I have been trying this also recently. My problem is that the photo-coupler consumes too much current as for the battery power.

I guess you can try to implement pwm modulation of the led and synchronous reception at photosensor side. Experiment with duty cycle to achieve best combination of power consumption and sensitivity constraints .

 

[Davechika]

Heart beat monitoring

Hello,pls nacccizo i need yuor help on heartbeat and temperature monitor using 8952 microcontroller which is interfaced to pc via serialport.

Thanks for your anticipated favourable response

 

[karesz]

Re: Heart beat monitoring

...photo-coupler consumes too much current as for the battery power.

...try to implement pwm modulation of the led and synchronous reception at photosensor side. Experiment with duty cycle to achieve best combination of power consumption and sensitivity constraints .

This would my idea too, then the most sensitive detection means sinchron switced with your sender
Trough PWM modus (or simpler adjusted/changed LED-pulsewidth) you can find a minimum pulslength what your electronics need to function, & so short is ilghtning as possible= saves battery power...

If you apply spetial wavelength of light: maybe you can be more sensitive to blud!

K.

 

[dimos.projects]

Do you need theory or practical info like schematics, etc.? because some time ago I did a HB monitor with plethysmography (IR light). And I can help you with some info.

Added after 25 minutes:

This is the prototype in action.

\[

plz help me out in sme pactical work.mine id is engr_faisal2002@yahoo.com

 

[azeem subbhani]

Re: Heart beat monitoring

hello narccizzo
my final year project is also related to heart beat monitoring
can u give detailed info about your project(Heart beat monitoring)
I'hv need it