Need help with my final year project...

[navarro_boyz]

Hi guys.

I am a final year student of Beng Electrical and Electronic.I am currently doing a project titled "heart rate measurement using fingertip" by Dogan Ibrahim and Kadri Buruncuk @ https://www.emo.org.tr/ekler/a568a2aa8c19a31_ek.pdf and i have modified the circuit and the programming based on my ideas.Therefore, I would like to ask your help in order to check whether there is any problem with my circuit diagram and also with my programming code since i have modified the project on my own.In the hardware side, it works fine but i could not simulate it on the proteus and i suspect that there might be a problem on the circuit part that i may have overlooked.If there is no problems,then only i can do the etching process.

The original circuit by Dogan Ibrahim and Kadri Buruncuk.
View attachment 60402

My modified circuit.
View attachment 60403

I added the buzzer on the pin 18 and the "abnormalities" led on the pin 17 of the pic16f784a.In addition,I also added the "on" indicator led with the +9V and the "reset push button" through the pin 4 of the pic16f84a.The programming also have been done according to the changes desired.

The original operation of the project...

BEGIN
Initialize program variables
Configure input-output ports
Display message “READY”
Wait until switch is pressed
Sum = 0
DO 3 times
Get count in 10 seconds
Count = 6 * Count
Sum = Sum + Count
ENDDO
Calculate the average, Rate = Sum / 3
Display the average on the LCD
END

My desired operation of the project...

BEGIN
Initialize program variables
Configure input-output ports
Display message “READY”
Display message "PRESS START"
Wait until switch is pressed
Sum = 0

DO 3 times
Get count in 10 seconds
Count = 6 * Count
Sum = Sum + Count
ENDDO
Calculate the average, Rate = Sum / 3

Normal heart rate
Display the average on the LCD
Beep once using buzzer

High or low heart rate
Display the average on the LCD
Beep three times using buzzer
Led blinking continuously

END

The rest of the information are attached together with this thread.

Note: For the proteus simulation, i have to use the opto-coupler because i could not find the IR diodes.

 

[alec_t]

there might be a problem on the circuit part that i may have overlooked

There should be a 100n decoupling cap in parallel with both C1 and C2, also at the supply pins of the PIC; but I doubt that would affect the simulation. Don't have Proteus so can't experiment.

i have to use the opto-coupler because i could not find the IR diodes

But the opto-diode has only DC current as shown, so IC2A doesn't get any signal via C4.

 

[be80be]

Tell me one thing how do you get your finger between that opto-coupler in Proteus

If you test as you posted it would just set there and give the same output unless you feed C4 a 60 beat pulse

 

[navarro_boyz]

Dear alec_t and be80be,

That's the problem.I don't know how to put an input signal over the IR sensors so that i can get an output.I have seen in various of forums where they said that you need to use a function generator but they didn't tell on how exactly to connect it in a circuit.I mean a picture as a guidance and it will save a lot of time overall.This is the place where i am really stucked and expecting someone to show me what is next to do.I know that I am just few steps away from completing my project.Obviously, I know that i can't get my finger on the opto-coupler in Proteus but how exactly that i can feed C4 with a beat pulse of 60?If possible, can u show which function generator to use or maybe a picture guidances will help?

 

[be80be]

remove the opto-coupler and feed C4 with a square wave at 60 cycles a sec

Are you using the Demo? Proteus 7 ?

I made one of these using a TSL230R Light to Frequency converter It worked nice only needed 4 parts that way a LCD,TSL230R,Pic chip and a red led.

I just have the demo so I can't post you the files but the pic should help you

 

[navarro_boyz]

Dear be80be,

This is the simulation that i have done on the proteus based on your guidance.

View attachment 60429

I get a result of 0 /min.There should be an output indication on D1 led where it will blinking for each output.

 

[be80be]

Hook a scope up on PIN6 INT RB0 see whats going to the pic

Did you set square wave value it is set 1/2 volt to start you need a 0 to 2.5 volts swing mim.

 

[navarro_boyz]

I didn't get any output on the oscilloscope.
View attachment 60430

 

[be80be]

I tested your circuit using Multisim It works A 1 volt peak square wave makes the led blink You have to set the pot RV1 to 3/4 the way on. It sets the output voltage.

If its midway I didn't get any output

 

[navarro_boyz]

Dear be80be,

The 3/4 setting on the pot is 7.5Kohm,rite? The 1 volt peak square wave that u have said is it dc or pulse in the generator section of the generator?

 

[karthikkrv85]

hai navarro_boyz

i found the mistake... it is very minor mistake. Please place a ground point for the op-amp section

 

[navarro_boyz]

Dear karthikkrv85,

I get an error message on the simulation.

 

[karthikkrv85]

may i know what error msg? i couldnt upload image here. dont know why..

 

[navarro_boyz]

I get this error message when i connect a ground at the bottom of the op amp circuit.
View attachment 60434

 

[karthikkrv85]

can you upload image of the modified circuit? here in my system, with that small changes, your circuit is working

 

[karthikkrv85]

i meant it is counting the pulses.. but not sure is that counts exactly or not.. may be you have to look into your code. I dont understand assembly language otherwise i could have helped you

 

[navarro_boyz]

can i have look at your circuit that you have said working in your system?

 

[karthikkrv85]

i tried to upload the image so many times it is giving error... that is the reason why i asked you to upload the image of the modified circuit...

 

[karthikkrv85]

Tell me how to upload the image here? i get error if i upload it

 

[navarro_boyz]

You can upload it in a free image hosting web such as postimage.org and share the link over here.