@OwenBrotherwood, This sensor from Adafruit is small, and will work on a fingertip, or clipped to an earlobe: https://www.adafruit.com/products/1093
It uses 4mA at 5v, and will also run at 3v, with just 3 wires – power, ground, and analog output.
The hardware is open source, and detailed here: https://pulsesensor.com/pages/open-hardware
@oesterle started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
@OwenBrotherwood, This sensor from Adafruit is small, and will work on a fingertip, or clipped to an earlobe:
https://www.adafruit.com/products/1093
It uses 4mA at 5v, and will also run at 3v, with just 3 wires – power, ground, and analog output.
The hardware is open source, and detailed here:
https://pulsesensor.com/pages/open-hardware