On 2/19/13 4:58 PM, Paul Cianciolo wrote:
Hello Folks,
I am working on a project intended to convert an analog ECG signal to
a voltage proportional the heart rate, The actual electrodes
instrumentation amp is pretty much working fine so no worries
there.
The problem is, and here is where the relationship to time nut comes
in. The signal output from the instrumentation amplifiers will be at
a rate of approx 60 BPM or pulses, up to perhaps 90 BPM.
Interestingly, I've been doing the opposite... given a rate, generate a
realistic pattern of beats.
The purpose of this apparatus is to print a rolling chart on the
screen of a computer of heart BPM and then try different technicues
of meditaion and calming technicues to lower my heart rate for short
periods of time.
My first tthought was a frequency to voltage IC like the LM2907 or
the 2917 but I get the impresiion from the data sheets that these
chips will not work at these very low 1 Hz applications,
Then I thought maybe one of the frequecy counters could be configured
as a rate meter and output a proportional voltage I need. No luck
here either. Te latter components seem tobe somewhat time relatedand
that is why I posted here.\\
A small microprocessor is your friend. Run your signal into an Arduino,
PIC, teensy (my current favorite) or whatever..
That way it can set the threshold dynamically, count time between zero
crossings, integrate over several beats, ignore skipped or extra beats, etc.
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