How is Heart beat counter working?

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theasus

Joined: 06 Jun 2009
Posts: 26

05 Nov 2009 18:27 How is Heart beat counter working?

I couldn't understand this circuit's operating.
Could you help me about this circuit details?

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theasus

Joined: 06 Jun 2009
Posts: 26

07 Nov 2009 18:16 Re: How is Heart beat counter working?

Is there anyone to answer my question??

Katak

Joined: 26 Aug 2009
Posts: 7

11 Nov 2009 2:50 Re: How is Heart beat counter working?

what l can see, you are using LM358 which is a Low Power Dual Operational Amplifiers. due to the very small voltages/signals received from the photosensor (the one under the finger), it need to be amplified significantly before proceed to the next stage.

it looks like Photoplethysmography (PPG) to me..