Heart beat sensor

[jackjosephtz3]

Thanks, I managed to do all the connections perfect BUT I just cant get the RED LED to blink according to the heart beat. What should I do ?

And am trying to write the program in AVR mega 8,, I sow your project " heart rate counter " can you please help me with the code...please.

[goeb1]

@jackjosephtz3 writing code will not help at this stage if the led is not blinking. I can't give you more help than there is in the provided link in the video description.

[jackjosephtz3]

@goeb1 its so surprising, how much time i have spent to get the LED blinking and yet it works so easy for you... I admit I cant move on to coding, so will you please just help me with the resistor values your using for the TCRT5000 plus the value on the 10K potentiometer . @goeb1 : I have read the link >1000 times, that's were i got your link. please help pal...

[goeb1]

@jackjosephtz3 read my comments (goebish) in the link, I say I used a 68 ohm + a 2K pot in series to drive the IR led. I would say my 2K pot is set at about 1200ohm, but YMMV.

Are you using a MCP602 as opamp ?

Don't think it worked on my first try, I had to fiddle a bit to make it blink ;)

[jackjosephtz3]

hi its me again, may i know how you connected your TCRT5000, coz when i connect i cant see it glowing with a camera, i even tried your circuit on the video.. please help

[goeb1]

@jackjosephtz3 it's connected exactly as in the link in the description.

[jackjosephtz3]

- Year I can see the IR light through camera.

- I drive the IR LED with a 68Ohms + 500Ohms Potentiometer ( in series ).

- NO! Am using LM358 opamp

[goeb1]

@jackjosephtz3 I first tried with a LM358 but couldn't get it to work, I think you've to change a few values and/or capacitors, but I couldn't tell how to make it work, go get a MCP602 ;)

I also think that a 500 ohms pot is not enough with the TCRT5000, I had to use a 2k ohms one to achieve the best sensitivity, and it's set over 1k.

[jackjosephtz3]

Thanks for the heads up! BUT I have another problem,

1). I did the circuit but I cant get the RED LED to blink according to the heart beat. Am using a 470 Ohm resistor in series with the RED LED,

2) When I place my fingre on the sensor, the output stays still at 0.03V.

[goeb1]

@jackjosephtz3 can you verify with a camera that the IR Led is lit ?

How do you drive the IR Led (how much resistance) ?

Are you using a MCP602 opamp ?

[jackjosephtz3]

Thanks allot that really helps.. Just curious, what resistor value are you using for the sensor IR detector (am using the same sensor TCRT5000).

I like the Bluetooth Heart beat rate monitor project.

Do you think you can help me demonstrating the same project but using RF module (315/435Mhz). Am really struggling with the interface...

PLZ help......

Thanks.

[goeb1]

@jackjosephtz3 I use a 68 ohm resistor + 2k pot in series to drive the IR LED, the pot is for easy tuning.

315/435 MHz modules are easy to use at least on the Arduino or with an AVR w/ Arduino bootloader and the VirtualWire library.The drawback is they are not very reliable (lots of dropped packets)

[goeb1]

@jackjosephtz3 in fact I think I see what you want to do, and this doesn't even require VirtualWire library.

You only have to connect the opamp's output pin to your RF TX module data pin. Then connect the data pin of the RX module to an input pin on your mcu, then poll this pin state or trigger an interrupt when its signal rise.

[goeb1]

You can also see my other videos where I send the beat over bluetooth to an android phone.

[jackjosephtz3]

Great work.... Am actually doing the same projet but incorporating wireless transmission of the heart rate. Plz tell me, can i actually see the final output signal on an OSCILLOSCOPE apart from the blinking LED result.

Thanks..

Plz reply ASAP if possible....

[goeb1]

@jackjosephtz3 you can see it on an oscilloscope but this will be a conditioned / filtered signal, not an actual 4 phases heart signal waveform.