Can I use an electrical contact as an electrode in a low cost heart rate/pulse rate monitor applicat

It will be pressed against the skin on either the finger or wrist.

I might use two of them slightly spread apart.

The signal will feed into an instrumentation amplifier with high CMRR.

Can I use an electrical contact as an electrode in a low cost heart rate/pulse rate monitor application??

Be careful. Either use battery operated gear, or if you must use AC line power you need to use isolation transformers rated for medical applications (they have much lower interwinding capacitance, and much higher isolation (insulation) voltages than %26quot;standard%26quot; transformers.

Make absolutely sure that any leakage currents from the instrumentation amps do not run a path through the heart with more than a few microAmps. Use lower valued bias resistors from the inAmp inputs to common to provide an easier path for bias currents (other than through the body).

As for the electrodes, any non-corrosive, non-oxidizing metal (nickel-silver plated, gold plated, platinum plated) wire or contact will work as a skin electrode.

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