ckt using LDR

[itzneona]

hi,
I'm planning to work with a simple ckt. Just have only few
ideas about the ckt.
following are the details:

the ckt is meant to be a, heart pulse detecting ckt.
main principle:
finger tip is to be placed in the gap between a LED and a LDR, so
that at each time the heart pumps,the pressure at tip changes.
(OR),
i.e.,during respiration,while breath in , blood gets oxygenated.thus
haemoglobin absorbs light from the LED and less light is sensed by the
LDR.corresponding analog voltage is obtained at the output.

This output has to be converted into digital form using the A/D-
convertor module of any microcontroller(amplification is required with
high gain).The final output has to be displayed in the CRO.

I believe you could help me with the ckt, its a kind of urgent,(max 4
days more).



Thanks,

Neona.

 

[Tim Wescott]

itzneona wrote:

hi,
I'm planning to work with a simple ckt. Just have only few
ideas about the ckt.
following are the details:

the ckt is meant to be a, heart pulse detecting ckt.
main principle:
finger tip is to be placed in the gap between a LED and a LDR, so
that at each time the heart pumps,the pressure at tip changes.
(OR),
i.e.,during respiration,while breath in , blood gets oxygenated.thus
haemoglobin absorbs light from the LED and less light is sensed by the
LDR.corresponding analog voltage is obtained at the output.

This output has to be converted into digital form using the A/D-
convertor module of any microcontroller(amplification is required with
high gain).The final output has to be displayed in the CRO.

I believe you could help me with the ckt, its a kind of urgent,(max 4
days more).

1: AYPFAE (Ask your prof for an extension)
2: ths int txtng, u hv a hl kbd (this isn't texting,
you have a whole keyboard)
3: YUTMCAWNP (you use too many cryptic abbreviations,
we're not psychic)
4: WNHTDYWFY (we're not here to do your work for you)

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

 

[George Herold]

On Feb 22, 12:30 pm, Tim Wescott <t...@seemywebsite.now> wrote:

itzneona wrote:
hi,
        I'm planning to work with a simple ckt. Just have only few
ideas about the ckt.
following are the details:

the ckt is meant to be a, heart pulse detecting ckt.
main principle:
   finger tip is to be placed in the gap between a LED and a LDR, so
that at each time the heart pumps,the pressure at tip changes.
                                             (OR),
i.e.,during respiration,while breath in , blood gets oxygenated.thus
haemoglobin absorbs light from the LED and less light is sensed by the
LDR.corresponding analog voltage is obtained at the output.

This output has to be converted into digital form using the A/D-
convertor module of any microcontroller(amplification is required with
high gain).The final output has to be displayed in the CRO.

I believe you could help me with the ckt, its a kind of urgent,(max 4
days more).

1: AYPFAE (Ask your prof for an extension)
2: ths int txtng, u hv a hl kbd (this isn't texting,
    you have a whole keyboard)
3: YUTMCAWNP (you use too many cryptic abbreviations,
    we're not psychic)
4: WNHTDYWFY (we're not here to do your work for you)

--
Tim Wescott
Control system and signal processing consultingwww.wescottdesign.com- Hide quoted text -

- Show quoted text -

Yeah I'm assuming the LDR is light depenedent resistance.. but who
knows.

What kinda LED are you going to use Neona? When I hold my finger up
to the room lights not very much light get through. (You are going to
have really small signals.) You might try sensing through the 'webs'
between your fingers.

Do you know what wavelength(s) hemoglobin abosrbs?

and why do you want to go to all that work to make your signal digital
and then display it on a CRO... (Cathode Ray oscilloscope?)

I'd first try a photodiode for sensing the light...

George H.