IMHO, the patent (https://patents.google.com/patent/US4813682A/en?oq=4813682 https://patents.google.com/patent/US4813682A/en?oq=4813682) has more useful info th

IMHO, the patent (https://patents.google.com/patent/US4813682A/en?oq=4813682 https://patents.google.com/patent/US4813682A/en?oq=4813682) has more useful info than this post: A television game apparatus according to this invention reads white picture data from a program ROM (6) to transfer it to a video RAM (8) and displays, on a television monitor (11), the white picture data, together with target or other data read from a character ROM (9). When a pistol (4) is leveled at a target on the screen of the television monitor (11) and the trigger is pulled, a switch (44) is closed to produce a trigger signal, on the basis of which black picture data is read from the program ROM (6) and displayed on the television monitor (11). Immediately after the black picture was displayed, the white picture is displayed in the next frame in the position where the target was displayed just before and/or around the periphery thereof. The light from this white picture is detected by a phototransistor (41), whose detection signal, when extracted by a filter (45, 46), is used as a detection signal from the target. Thus, there is no danger of mistaking the light from an illuminator for the light from the target. I remember the trigger would cause a flash on the screen. Or skip the post and the patent and just watch this youtube video: https://youtu.be/Nu-Hoj4EIjU?t=520 https://youtu.be/Nu-Hoj4EIjU?t=520