Re: [Phys-l] Apps for iPhone

[brian whatcott <betwys1@sbcglobal.net>]

On 6/1/2011 8:52 PM, Derek Chirnside wrote:
> My first post here since 1999.  Just rejoined the list after a small
> digression into other fields.  The world has changed in the meantime.
>
> Does anyone know of any projects on using an iPhone as a simple datalogger?
> eg a timer (simple break a light beam to start, break a light beam to stop)
> - or even recording a lot of time intervals. Or a counter.
> I'm assuming the OS inside is able to do this, I'm just not sure how easy it
> is.
>
> I did a quick search: but most references in the list were "Sent from my
> iPhone"
>
> -Derek
A fellow I worked with showed me a stunt app on his iPhone: put your 
finger against
(one of the ) lenses and point it towards the Sun, he said.

The app displayed my pulse rate - which is apparently helpful to folks 
who want to
set their resting pulse rate down by graduated exercise.

A few days later I showed him the stunt app on my dedicated device: a 
pulse oximeter:
%oxygen saturation and pulse rate. This is the device that goes for $25 
on up, and has
an interesting operating principle: Two LEDS shine through the finger 
nail: one is
 red the other infra red:
the spectral sensitivity differs as between arterial and venous blood. 
To sharpen
 the match to O2 saturation,
 readings are taken at the systole and diastole, and the diastolic 
reading is subtracted
from the  systolic reading to subtract common mode artifacts from the 
systolic,
 arterial oxygen rich reading.

Brian W