Can Si1153/33 sensors be used for ambient light sensing? How to convert ALS results to LUX values? Any example code available?
Only Si1153-AA00-GM and Si1133-AA00-GM parts can measure ambient light. Si1153-AA09-GM and Si1153-AA9X-GM parts cannot measure ambient light due to the on-die 940nm filter.
There's no simple equation to convert ALS measurement results to LUX values by any means. The only solution is to perform tests under certain light sources and calibrate ALS results against LUX values read from a LUX meter. Then find the ratio or formula to estimate LUX values based on ALS measurement data. Since it's an estimation, the accuracy won't be anywhere close to a LUX meter. Si1153/33 sensors CANNOT be used in LUX meter type of applications, but can still be used in applications that only require an approximate LUX level.
We've built a model to use 3 different channels' ALS measurement results to estimate LUX values. The example code is attached. However, the model is overly complicated and we recommend the customer to only use that as a reference and develop their own equation to estimate LUX.
Silicon Labs doesn't support ALS calibration for any applications.