Please give me just a minute(which sensor is best)

[farsun]

I am making a project which reads human pulse and tells that pulse is normal or not.
i want to know that which sensor should i use to sence the human pulse.

moreover if you have some idea for this project share it with me i will be very thankfull to u.

 

[Optikon]

OK 1 minute... start.... NOW!

Umm, I've seen everything from simple red LED with CDS photo resistor to
pyro sensors. Another common method is infrared LEDS with infrared sensitive detector. Of course, you'll have to condition your received signal with amplifiers & possibly fiters.. but for best results use a(TIMES UP!)

 

[farsun]

Thank you for giving me 1 minute.but i think your witing speed is very slow.in one minute (if you write speedly) you can write a full article
just joking

if you can help me more i will request you to do

i don't want to use infrared.
i just want a sensor, and if you can help about counting pulse then pleseeeeeee

 

[Optikon]

Thank you for giving me 1 minute.but i think your witing speed is very slow.in one minute (if you write speedly) you can write a full article
just joking

if you can help me more i will request you to do

i don't want to use infrared.
i just want a sensor, and if you can help about counting pulse then pleseeeeeee

Well, I have never seen a sensor package just for this application. You will need a light source & light receiver of your choice.

Infrared has the advantage of being able to buy powerful transmitters. but, if you dont want to use infrared and need to count them, have a look at this design:

**broken link removed**

I havnt a clue if this works or not but this guy does pretty good work and it looks reasonable. The output gets you a digital signal which, you can count with a microcontroller or some counter logic. You can use a high intensity red LED with a CDS photo cell.

Whatever you choose to do, you will need similar signal processing to extract the AC portion of the pulse signal and turn that into a digital pulse train.

 

[dknguyen]

Do you have to use optical sensors to sense a pulse? It seems to me a tactile sensor might be easier to work with...actually how would you even use IR to sense a pulse? Enlighten me please.

Personally, an idea that comes to my mind is to tighten a balloon or air bag around the arm and then use a microphone on the bag and try to listen for beats (but you have to filter out the noise and stuff too so it takes some signal processing). I'm not very imaginative at this, hehe.

 

[Nigel Goodwin]

Do you have to use optical sensors to sense a pulse? It seems to me a tactile sensor might be easier to work with...actually how would you even use IR to sense a pulse? Enlighten me please.

You shine it through the body, usually through a finger or an ear lobe, the blood pumping through the body modulates the amount of light passing through - you amplify and filter this.

Sensors on machines in gyms seem to work off skin resistance changes?, at least you grip a handle with two metal tubes seperated by an insulated gap.

I once went on a visit to a coal powered electricity generating station, they use acoustic sensors and chart recorders to 'listen' for any developing problems before they cause trouble. As part of a demonstration the engineer fixed acoustic sensors on people and printed out their heart beats on a chart recorder. It was really an interesting visit!.

 

[farsun]

hello!
I have a project of logic probe simply, but i want to use it to accsess the circuit cury as wel as the to detact the pulseof human and count it, if it <72 than he han low ,and if >72 then he have high.
now i made the circuit for the logic probe,but for the detection of very light pulse of heart we need a sensor that detect this light pulse.i think we can use here the cystal microphone but if it is not available than what is its alternate sensor or detective of light pulse.