This component is used during the calibration procedure, which is described in detail in the PPT Studio section later in this guide. The rig's center determines the tracking space origin. The rig's orientation, as shown by the +X and + Y markers printed on the rig, determines PPT's coordinate system. When powered on, the 4 LEDs blink in sequence. Each rig corner has both a red visible LED and blue IR LED. The visible LEDS are indicator lights to show when the IR LEDs are active.
When the battery is low, the red visible IR lights will be dim and the cameras may have trouble picking up the IR lights. The single 9V battery can be replaced by opening the circuit box attached to one side of the calibration rig.
Each pair of the LEDs (IR LED and visible LED) are in serial so if one of them is broken, the other one will not work either.