Fig. 3.

Experimental setup. The handheld device was attached to the face of the T-10 such that the sensor was able to capture illuminance readings of the background. The T-10 was connected to a laptop computer through a proprietary RS232 cable because due to Android OS limitations, the handheld devices were not able to directly interface with the T-10. The T-10 reading and writing program was run on the laptop so that it was able to read data from the T-10 and write measurements into a text file which was used for data analysis. A time stamp synchronized each user response from the DENOTE application with the exact illuminance measurement