On Tue, Feb 19, 2013 at 04:58:04PM -0800, Paul Cianciolo wrote: > Hello Folks,
First, I cannot speak for the list, as I'm quite new here, but in general 'Thread Hijacking' is frowned upon :) (read: start your own thread :) > 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. > 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. That doesn't sound to me like you would actually need a Voltage, i.e. some other Information from which you can deduce the current BPM would be fine as well ... > 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 1Hz > applications, > Then I thought maybe one of the frequecy counters could be > configured as a rate meter and output a proportional voltage > I need. I wouldn't count the frequency directly, instead, I'd simply count the intervals, with a counter running at a known frequency, for example, with a 1kHz or maybe 1MHz clock, which can be easily done with a $1 microprocessor The 'counts' for each interval are inverse proportional to the current BPM, with some averaging you should get a reasonable result to display on screen. > No luck here either. > Te latter components seem tobe somewhat time relatedand that > is why I posted here.\\ > Thank you for reading this and for any suggestions you folks might offer. HTH, Herbert > PaulC > W1VLF > 1Hxz > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
