I recently needed to measure how different materials affect light transmission for a gardening project.  This seemed like a perfect fit for an Arduino project based around the TSL2561 Light sensor.

It can display the raw "Visible light" count from the sensor and then the calculated Lux.

I used the following parts in this project:

• Arduino Uno
• TSL2561 Digital Light Sensor
• 16×2 LCD
• LCD I2C / SPI Backpack

Optional (but definitely helps keep everything tidy):

• Lady Ada’s Bento Box