Description:

The VCNL4040 is a handy two-in-one sensor, with a proximity sensor that works from 0 to 200mm (about 7.5 inches) and light sensor with range of 0.0125 to 6553 lux.To give you some ability to tune your measurements for your situation, the VCNL4040 lets you adjust the integration time (how long light is being measured) to set the sensitivity of your measurements depending on the lighting conditions. With an integration time of 80ms, since the sensor is only collecting measurements for a short period of time, each measured bit of light represents a larger amount of light. For this reason the maximum range in lux for the 80ms integration time is 6553.5 lux.

If you use a longer integration time and get the same amount of light measurements "events", you know that there is comparatively less light because we're waiting around longer for light to show up and getting the same number, meaning the rate of light events is lower. For this reason at the maximum integration time of 640ms the VCNL4040 will only measure up to 819.2 lux.

It is also worth keeping in mind that as you increase the integration time you are also increasing the sensitivity and resolution within the measurement range.In addition to adjusting the sensitivity of light measurements, you can change the current and duty cycle of the IR LED that powers the proximity detection to adjust how sensitive proximity measurements are