Arduino: TKLightMeter v 0.1: A Simple Irradiance Meter Using TSL235A
This little gadget is primarily for Joule Thief research, where the relative brightness of an LED must be compared or monitored as conditions change.
The TSL235A is a small sensor that converts light intensity (irradiance) to frequency of a square wave output. The response is linear over a wide range and the device is very sensitive indeed.
The Arduino FreqCounter library provides highly accurate frequency measurements using built-in capability of the ATmel microprocessor. I modified the example sketch in the Library to include the LCD display features and the conversion of the Frequency data into irradiance. I just did this last part very roughly by eye so to have something to display; it’s not yet accurate in terms of the irradiance value. I’ll do some further calibration later on to get the accuracy, but for now the meter is still very useful for relative comparisons.
I ordered the sensor from SparkFun Electronics. My program sketch is here:
http://www.mediafire.com/view/phrb1819c107zy6/TKLightMeter1.ino
Thanks for watching!