Problem with a heartbeat monitor circuit

[Audioguru]

Heartbeat Monitor

R12 biases the input of U2 opamp at 0V and is part of the Butterworth second-order highpass filter. Do not change it.

C6 is part of the Butterworth second-order lowpass filter. Do not change it.

Connect an oscilloscope to the output to see all the noise from the lousy old 741 opamps.

The AD620 intrumentation amplifier will not work unless its inputs are biased at 0V usually with the right leg connected to an inverted common-mode signal.

 

[ranggaperdana_06114]

Re: Heartbeat Monitor

how about this circuit ?
if i not wrong this electrode connections use einthoven triangle theory so i use that for my circuit, it's true and it's okay ?
tanx

 

[Audioguru]

Re: Heartbeat Monitor

The instrumentation amplifier will not work unless its inputs have a 0V reference with resistors or through a path through the patient or with a right leg inverted common mode voltage through the patient.

The datasheet of the AD623 shows that its noise is 10 times higher than the AD620. Try it to see if it is acceptable.

 

[ranggaperdana_06114]

Heartbeat Monitor

see my message before...
tanx

 

[Audioguru]

Heartbeat Monitor

Now that the patient's leg is connected to 0V the circuit might work. Try it.

 

[ranggaperdana_06114]

Heartbeat Monitor

how about the sensor,can you tell about it and image of it?
how to use it?can explain that?
tanx

 

[Audioguru]

Re: Heartbeat Monitor

how about the sensor,can you tell about it and image of it?
how to use it?can explain that?
tanx

There is no sensor. The conductive pads that connect the ECG circuit to the patient are called electrodes. They are sticky. Look in Google Images.

 

[ranggaperdana_06114]

Re: Heartbeat Monitor

what is the signal output from electrode? cause when i measure it with osciloscop i get the sinus signal from electrode that i placed at RA & LA.
what is characteristic of electrode ?
where i can get the theory of all about electrode?
tanx

 

[Avni]

Query

hiii........
I am making my minor project i.e. digital heart beat counter . I am not finding the pcb design of this project so please help......

 

[zlatkoMM]

Re: Heartbeat Monitor

Oh my what a lie --- it's RIME

Audioguru say:

Elcos have a tolerance of +100% and -50%. Pretty bad.

Are you from Neptun - TOLERANCE +100% Ha Ha hja

IS anybody else know for that tolerance !!!!! ????? HA HA !!!

 

[bitstream]

Re: Heartbeat Monitor

@zlatkoMM

Don't really get what the reason for your hysteric laugh could be?

Audioguru may have exaggerated a bit - nowadays it's more likely to find –10/+50% or better Alu-foil parts - but if you take some older ones, you still have a chance to get a +100% capacitance variance!

Manufacturing process variation of Alu foil capacitors was so big that they had to "under-specify" them: e.g. they produce a batch that have a "real" values in the range of 8 uF to 20 uF and name them 10 uF capacitors...
...and there comes the +100% variance -> 20 uF (real capacity) = 10 uF (specified) + 10 uF (variance = 100% of specified 10 uF)

Why under-specifying... well, mainly because they are supposed to be used as power storage and you would like to have rather more than less capacitance (more is always better, less is harmful if rated as calculated i.e. no reserve )

Make any sense to you now???

P.S. I would suggest you to think and investigate a bit BEFORE overreacting like this (to a post from a resourceful contributor) and risking to reveal your level of competence...

 

[zlatkoMM]

Re: Heartbeat Monitor

give me a break...
man is too smart....
like always....

 

[ranggaperdana_06114]

Re: Heartbeat Monitor

AudioGuru, you know our body is like antenna so our body receive all frequency arround us.i know this can mess up the signal of heart beat, then how i can remove this mess up?
tanx

 

[akss_here]

Re: Heartbeat Monitor

for that purpose only we are using a range of frequency for study...

other will be extracted by filter... isn't it..

 

[Audioguru]

Heartbeat Monitor

The signals pickup by a person are common-mode signals that are cancelled by the common-mode circuit that feeds a negative signal back to the person to cancel the common-mode signal.

 

[kender]

Re: Heartbeat Monitor

what is range frequency of ecg ?

Some have a frequency range of 0.03Hz to 100Hz.

Up to 1kHz is relatively common. It's possible to count pulse with 100Hz bandwidth, but the finer structure of the ECG/EKG would be lost.

 

[akss_here]

Re: Heartbeat Monitor

market available ECG instrument if you will search the range will be about
0.5 Hz to 40Hz... anyhow its works well also in case 1 Hz to 250Hz... just filter out electrical and enviornmental noise out of it... the ECG inputs will vary within 0.5mV to 2mV

 

[shon]

Re: Heartbeat Monitor

can u plzz send the details of the project heartbeat monitor..
plzzz m email id z pretty_sonal16@yahoo.co.in

 

[princez]

Re: Heartbeat Monitor

Hi,

am designing a heart rate monitor circuit that will count the number of heart beatings per minute. i read about infra red and photo diode combination for this purpose but can i use a microphone instead of this optical sensor???

which one would be a better choice ?

(P.s help me , I've posted on other threads as well, but didn't get any response)

 

[vjfaisal]

Re: Heartbeat Monitor

Dear Audioguru

Regarding your Attachment in this topic:

Q: would you plz tell me in the attachment , there is a component "ADS8321" and REF3125 what is this ?? and what its work.

Is this Circuit attached in this theard is workking condition or not ??


Kindly reply me as soon.....


Thanks


Regards