Introduction
There is a range of breakout boards with digital ambient light sensors available. This post lists some of the more common. Analog ambient light sensors (“photoresistors”) are not covered.
BH1750FVI
BH1750FVI is a digital Ambient Light Sensor IC for I2C bus interface. It is possible to detect wide range at High resolution (1 - 65535 lx). It is produced by ROHM that also provide a datasheet.
The component is outdated, there are more advanced ambient light sensors available. You get these at 2 USD at Banggood.com.
Adafruit TSL2591
The Adafruit TSL2591 High Dynamic Range Digital Light Sensor is more precise, allowing for exact lux calculations and can be configured for different gain/timing ranges to detect light ranges from 188 uLux up to 88,000 Lux on the fly.
Adafruit TSL2561
The Adafruit TSL2561 Digital Luminosity/Lux/Light Sensor Breakout contains both infrared and full spectrum diodes. That means it can separately measure infrared, full-spectrum or human-visible light. But it has lower dynamic range compared to the TSL2591.
This module is available in Sweden from elfa.se.
Adafruit SI1145
The Adafruit Digital UV Index / IR / Visible Light Sensor extends all the way to Ultraviolett (UV) light. That could be of interest when determining the bacground light source, or for assessing needs of sun protection (as a completely different usage).
Sensor Project Nano