stethoscope design

I need to design a stethoscope for my college project that finds heart rate respiratory rate nd detects co2....nd displays the results on an LCD nd on the computer.....please help!!

A tricorder?
Heart rate is easy, but for rate of respiration you would need something that goes around the chest and that is no longer a stethoscope.
Do you mean CO2 level in blood?

detects co2....nd

"nd" is nitrogen dioxide?

This is a good project, and the first thing to do is google every topic, as there are certainly
1000s of pages of info out there about how to measure these things.

Once the proper sensors have been identified, then one determines how to connect them to
Arduino.

AWOL:

detects co2....nd

"nd" is nitrogen dioxide?

That's how kids these days spell the word and when they are texting to their girlfriends. Kids who are doomed to fail in school often get confused and think it should be spelled that way all the time. Even when trying to get help from educated people. That usually leads to their demise and eventual flunk out. It gets really entertaining when they use that sort of stuff in class assignments then get mad when the whole thing gets marked with a zero and a note that I will not waste my time tryingto read it.

please help!!

Please explain what kind of help you are looking for as that is far from clear.

Just google for arduino sthetoscope gave:

Hello,
My name is Jason and I do software/hardware design for co2meter.com. We have several different sensors that would be useful for this, as well as several application notes specifically for interfacing our sensors with arduino.

As for the heartbeat, there are a few low cost solution online. I saw one on makershed that looked promising.

If you have any questions about wiring or programming for a co2 sensor I will be more than glad to help.