Heart rate monitor???
Dan Michaels email (remove spam text)
Dan Lloyd wrote:
>You can buy bands that go around your chest that actually transmit pulses,
>via RF, to a receiver (this is the kind of things used for professional
>cycle computers). They are about $80 but I cannot remember the
>source.....maybe it was King Cycle?. You can also buy "clip on" units but I
>am not sure about their output.
Polar is the big producer - and has the main patents. You can pick
up the belt signals with an LC ckt+amplifier tuned to between 1 & 5
Khz - forget exactly.
>As opposed to that, you could always do some signal processing on an
>electrode output or use an infra red sensor to detect "pulses" of blood
>moving under the skin (usually on fingers, wrist or ear lobes).
IR devices are not as good as the Polar belt/watch units for activity
You can tape electrodes to the chest, like they do with EKGs, and
feed them to a fairly simple differential amp [basic signals are
couple of mV], but now you have to worry about safety/electrocution
concerns, and severe regulatory issues with the FDA.
You can probably find ckts/etc by doing a search at google.com.
- Dan Michaels
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