Turn a current cost cc128 meter into a footcandle light meter

Here's a current cost TX unit modified to show ambient light levels. I added a photo-transistor to input ch1, and the unit now acts as a foot-candle calibrated light level meter. It has good dynamic range, from darkness  to direct sunlight. Its possible to pair the TX unit as one of the 9 sensor channels on a CC128 meter - this way the light level doesn't get added to the house power total  - and adding a livebox flashed with HAH you can easily send the data to Pachube.

Below you can see the photo-transistor with an excessive blob of hot melt glue ...

How to calibrate the unit to footcandle and convert footcandles to watts/meter

                  

Below is the feed on pachube - reading in footcandle.

pachube for the last 90days

Adding an Arduino to a HAH livebox