A projector system comprising: a computing device; at least one projector configured to communicate with the computing device, the computing device being configured to cause the at least one projector to project an image or a structured light pattern, the structured light pattern comprising features that can be uniquely mapped to locations in the structured light pattern; a screen; and an apparatus comprising: a light sensor; a body comprising the light sensor, the body configured to position the light sensor proximal to the screen, facing the at least one projector, and between the screen and the at least one projector, to detect light from the at least one projector rather than to detect light reflected from the screen; a communication interface for communicating with the computing device; and, a processor configured to: transmit a request to the computing device to project the structured light pattern using the projector; and when at least one pixel in the features of the structured light pattern projected by the projector is detected at the light sensor, transmit a detection indication of the at least one pixel to the computing device, the computing device being further configured to: receive the request and control the projector to project the structured light pattern; receive the detection indication; determine a location of the light sensor within the structured light pattern as indicated by the detected at least one pixel based on the detection indication; control the projector to stop projecting the structured light pattern; and, control the projector to project the image with an edge of the projected image aligned with the dectected at least one pixel. a computing device; at least one projector configured to communicate with the computing device, the computing device being configured to cause the at least one projector to project an image or a structured light pattern, the structured light pattern comprising features that can be uniquely mapped to locations in the structured light pattern; a screen; and an apparatus comprising: a light sensor; a body comprising the light sensor, the body configured to position the light sensor proximal to the screen, facing the at least one projector, and between the screen and the at least one projector, to detect light from the at least one projector rather than to detect light reflected from the screen; a communication interface for communicating with the computing device; and, a processor configured to: transmit a request to the computing device to project the structured light pattern using the projector; and when at least one pixel in the features of the structured light pattern projected by the projector is detected at the light sensor, transmit a detection indication of the at least one pixel to the computing device, the computing device being further configured to: receive the request and control the projector to project the structured light pattern; receive the detection indication; determine a location of the light sensor within the structured light pattern as indicated by the detected at least one pixel based on the detection indication; control the projector to stop projecting the structured light pattern; and, control the projector to project the image with an edge of the projected image aligned with the dectected at least one pixel. a light sensor; a body comprising the light sensor, the body configured to position the light sensor proximal to the screen, facing the at least one projector, and between the screen and the at least one projector, to detect light from the at least one projector rather than to detect light reflected from the screen; a communication interface for communicating with the computing device; and, a processor configured to: transmit a request to the computing device to project the structured light pattern using the projector; and when at least one pixel in the features of the structured light pattern projected by the projector is detected at the light sensor, transmit a detection indication of the at least one pixel to the computing device, transmit a request to the computing device to project the structured light pattern using the projector; and when at least one pixel in the features of the structured light pattern projected by the projector is detected at the light sensor, transmit a detection indication of the at least one pixel to the computing device, the computing device being further configured to: receive the request and control the projector to project the structured light pattern; receive the detection indication; determine a location of the light sensor within the structured light pattern as indicated by the detected at least one pixel based on the detection indication; control the projector to stop projecting the structured light pattern; and, control the projector to project the image with an edge of the projected image aligned with the dectected at least one pixel. receive the request and control the projector to project the structured light pattern; receive the detection indication; determine a location of the light sensor within the structured light pattern as indicated by the detected at least one pixel based on the detection indication; control the projector to stop projecting the structured light pattern; and, control the projector to project the image with an edge of the projected image aligned with the dectected at least one pixel.