I'd like to build a small, portable heartbeat logger - so I can log my heartbeat as it changes during exercise, rest etc.
So my question is, whats a good way to detect a heartbeat? (You could read that as how do some heartbeat detectors work?)
Pressure sensor in the wrist? Electical signal from the chest?
Any suggestions?
Hi, they typicaly use a led/photocell arrangement, placed either side of a finger or earlobe. If you use both visble and red leds you can monitor your oxygen saturation as well.
The Polar chest-transmitter type uses two 3" x 8" conductive fabric pads (about 7" space between centers) on a band around your chest. The PCB is about 1" square and powerd by a single inexpensive CR2025 Li cell. The pads have to be moistened before use.
If you use this method, it should go without saying that low-voltage battery power is the safe way to go.
Best regards, Spehro Pefhany
^^^ Argh. make that 0.8"
Best regards, Spehro Pefhany
This method is utterly useless if there are motion artifacts.
See
Nonsense. See "Earpulse.pdf" on the S.E.D/Schematics page of my website. It was used on both an exercise bicycle and a treadmill.
...Jim Thompson
Virtually all commercially successful exercise devices use chest straps. Finger or earlobe devices are erratic nonperformers.
Tell ITC in Tempe... they've been remarkably successful building infrastructure for various OEM exercise machine manufacturers, using my design that's now nearly 30 years old.
...Jim Thompson
Thanks to everyone who replied. I tried the led/photocell arranegment and it works well enough for me.
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