Why does my Light Sensor show a really low reading even when the lights are on?

Question

Why does my Light Sensor show a really low reading even when the lights are on?

Answer

The readings from most Z-Wave Light Sensors depend on what the internal sensor is capable of providing.

For instance:


Of the above sensors, only the Aeon Multisensor 6 and the Fibaro Motion Sensor actually provide a true "Lux" reading, but even then those readings may not be what you were expecting.

When you look at the true definition of "Lux" you can see that the readings can vary by large amounts:

  • "Full daylight" - can be anything from 10,000 to 25,000 Lux
  • "Family living room lights" - can be as low as 50 Lux
  • "Very dark overcast day" - can be around 100 Lux

Our advice is to take some basic readings from the sensor in its' final location so that you get a true "real-world" indication – night with lights off, night with lights on and daylight.

Use these readings as a starting point and then build your logic around them!


Copyright Vesternet 2016

Updated: 18/02/2016