On/Off Control

MarkOne w/ Wifi
Pulling D5 to GND will turn off the IR LEDs. (HIGH is 3.3V)

MarkOne (non-Wifi)
Pulling the Control Pin to High (5V) will turn off the IR LEDs. The Control Pin is indicated in the figure below.
NOTE: This feature is activated for non-Wifi units shipped after March 01, 2016.