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I got one of those $1 heartrate sensors with the LED, and while I see there are lots of people who make it work, there are also quite a bunch that seem to fail.

My situation: I hook it up to 5v and use A3 as my analog input. When I power it up it starts reading 0 and then some random values, while the LED blinks chaotically - I'm assuming its initializing itself. Few seconds later the LED lights up fully and I assume that's when its ready to operate. I put my finger on the sensor and nothing significant happens. I notice that the harder I push on the sensor the higher the analogRead values go, so its definitely doing something but not quite what I need. Occasionally I notice that I can see my heartbeat among the logged values but its such a slight change that I'd imagine it would be really hard to capture programatically - if for example the logged values vary from 475 to 480 then my heartbeats would be like 485-ish. Furthermore, depending on how hard I'm pressing the values could be in any range, not just the 400s.

My code is just reading the analog value and sending it over to an i2c output device. The read happens in intervals of 50ms.

On the hardware side I've got the sensor plugged into 5v with short jumper cables, but the output goes through about 50cm of cable because the devices are physically apart and my setup does not allow me to easily put them closer together.

Is there anything I can do to get this sensor to work?

5
  • A link to the exact sensor your talking about would probably help.
    – timemage
    Oct 24 at 11:57
  • @timemage I added a link, I thought they're quite famous.
    – php_nub_qq
    Oct 24 at 12:00
  • The general idea is, that specific one? no idea. pulsesensor.com is probably a better link, but at least now people can see what it is.
    – timemage
    Oct 24 at 12:03
  • Typically, the built-in led should blink at heart rate speed. If that works (which isn't the case currently, according to your description), you should be able to detect similar value changes and change rates in the signal line. Oct 25 at 10:26
  • your finger should be on there during the self-calibration at power-on, not after.
    – dandavis
    Oct 27 at 20:29

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