OPTICAL SENSOR - THE FUNCTION OF RED LED

Xherdan

The Optical sensor is constituted by 1xRed LED, 3xGreen LED, plus a single IR sensor. What is the function of the RED LED? Why is it always off during my activities?

cheekychimp

It's good to search the forum as this kind of question was already answered a year ago by tfarabaugh.

Here is a very interesting detailed answer from tfarabaugh in this link https://en.discussions.tomtom.com/spark-and-spark-3-runner-2-and-runner-3-473/where-is-the-red-heartrate-sensor-light-995001.

In summary - the red led light is permanently off, your watch is working perfectly without it, Tom Tom is not making use of the red led for anything (as yet). The photo is coming from a Tom Tom pre-production model from a long time ago.