Lightmeter - prototype

This is my lightmeter project for taking properly exposed photos with my Canon DSLR. I prefer simple solutions and quick building processes.

Requirements

• Some Atmel microcontroller with SPI, I2C and at least 6 GPIO pins (optionally with Arduino support). Currently I am using Arduino Nano for prototyping.
• BH1750 light intensity sensor
• Some BH1750 Arduino library (for example: here) - This is also usable with my code with little modifications
• Nokia 5110 LCD
• LCD5110_Graph Arduino library (from here)
• 3-4 tactile buttons (4 for the implementation of the HOLD function)
• Prototype board
• Wires for prototyping

Prototype board setup

Prototype board with HOLD button setup

Hold button is the rightmost button connected to D8

Simplified program workflow

Images 

Downloads

• Clone the sources with git from https://github.com/dzooli/lightmeter

References and additional information

• BH1750 Datasheet
• Another Arduino libraries for BH1750
• Arduino Project Hub - example
• Similar but simpler usage of this sensor
• Another DIY project
• A lux meter with similar components