Lux-O-Meter is a free, straightforward Android app developed by Heid Soft that allows you to measure light intensity using your phone's front light sensor. The app gives you the option to display the values in Lux or FC (foot candles) and provides a correction value for calibration if you have a reference device. Additionally, it offers an optional background-measurement mode that records long-term average values.

Lux-O-Meter is an ad-free app with no in-app purchases or data collection, making it a reliable tool for measuring light intensity without any distractions. However, it's worth noting that the value readings may vary from one device to another, depending on the sensor's quality. Overall, it's a simple and easy-to-use app that serves its purpose well.