From: Chuck Simmons
Organization: You jest.
X-Mailer: Mozilla 4.61 [en] (X11; U; Linux 2.0.33 i586)
Subject: Re: searching for a pulse rate sensor
Date: Sun, 19 Jan 2003 03:56:12 GMT
NNTP-Posting-Date: Sat, 18 Jan 2003 19:56:12 PST
Jim Thompson wrote:
> On Sun, 19 Jan 2003 00:13:59 +0100,
> "BarryNL" ,
> In Newsgroup: sci.electronics.design,
> Article: <firstname.lastname@example.org>,
> Entitled: "Re: searching for a pulse rate sensor",
> Wrote the following:
> |"Barry Lennox" wrote in message
> |> On 17 Jan 2003 18:18:39 -0800, email@example.com (Joe Blo) wrote:
> |> >I am designing a project where I need a pulse rate sensor.
> |> >I could scavange one from an off the shelf pulse-rate meter, but I
> |> >would rather get one with a data sheet that helps me to determine how
> |> >I can interface it to a microcontroller to read the pulse rate of a
> |> >human.
> |> I took a close took at the inside of one a while back, it had a
> |> plastic housing that went over your finger, with an IR LED on one side
> |> and a photodiode on the other. The theory is that the blood pulsing
> |> through your finger modulates the amount of IR reaching the
> |> photodiode.
> |These sort are notoriously unreliable. [snip]
> The one on my website is quite reliable... it was tested extensively
> on just about every conceivable skin color ;-)
You really need to work on the design to measure using a finger like
many pulse oximeters do. The ear is now used for measuring temperature
so it is sort of preempted.
... The times have been,
That, when the brains were out,
the man would die. ... Macbeth
Chuck Simmons firstname.lastname@example.org