Abstract: In one aspect, a device includes a processor, a visible light detector, an infrared (IR) detector, a projector, and storage accessible to the processor. The storage bears instructions executable by the processor to actuate the projector to project calibration images onto a projected whiteboard location and receive, from the visible light detector, at least one image of the calibration images. The instructions are also executable to receive at least one image of an IR emitter on a pen from the IR detector and calibrate a location of the IR emitter with respect to the projected whiteboard using the at least one image from the visible light detector and at least one image of an emitter on the pen.