Heartbeat Monitor using photoplethysmograph technique

[Akira Sakura]

photoplethysmograph simulation

hello all. I'm new here. i got problem with my project.
this my circuit.. i run it using PROTEUS SOFTWARE but then there is no output at D3 & D4. but D2 is ON. i hv replace LDR with R3 bcoz there is no LDR component in Proteus.
as for the input, i put 5V. can anyone tell me wat is the problem.
and wat is the actual output (pulse/wave) at pin 7 LM358?

 

[Audioguru]

ldr for proteus software

Of course there is no output because there is no input.
If your simulation program does not have an LDR then use an NPN transistor for R3 and feed it with a very low frequency signal.

 

[Akira Sakura]

ldr proteus

can i know how can i replace the LDr with NPN since LDR only have 2 pin?

 

[Audioguru]

heart beat ldr

An LDR conducts when it is exposed to light.
An NPN transistor conducts beween its collector and its emitter when it has positive base current.

Give the base of the NPN transistor a low frequency current and it will do exactly the same thing as the LDR.

 

[Akira Sakura]

ldr for proteous

thanks for the advice. it result an output. but, can u tell me how the output from the LDR which is in resistance will be input for the op-amp since op-amp only feed voltage as input?

 

[Audioguru]

photoplethysmograph circuit

Use the LDR as part of a voltage divider with a resistor in series with it. Then the resistance change of the LDR changes the current which changes the voltage across the LDR and across the resistor.