As we all know by now, light gun games that worked on a CRT TV do not work on a plasma or LCD screen. However, in recent years an arcade game based on Rambo was released:

As you can see in that video, there appears a working light gun, on a modern LCD screen. There's also no pointer on the screen as you see with Wii shooters.

My question: how does this gun work? Why does this gun work? Why haven't we seen any console games using this same tech?

closed as off-topic by Frank, Ben, user106385, Studoku, Aequitas Oct 7 '15 at 23:57

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Questions about Game Design and Development are off topic. This includes speculative questions about developer intent, with respect to both mechanics and narrative. You might want to ask over at GameDev.SE, but be sure to read their FAQ" – Frank, Ben, Community, Studoku, Aequitas

  • What does showing/not showing a pointer on the screen have to do with anything? – Broots Waymb Oct 7 '15 at 16:17
  • The fact that it doesn't seem to work like a Wiimote in the Wii's shooting games. – yesman Oct 7 '15 at 17:00
  • Wii games don't have to show a pointer... Of course they do, because it uses the sensor bar and using the Wiimote for sight would be idiotic. I'm assuming that if this Rambo game just uses the screen an no other sensors apart from the gun, the gun probably has a photoreceptor of some kind (no, you need a CRT for all technologies of this kind). – Broots Waymb Oct 7 '15 at 17:04
  • 1) there is no evidence that Rambo uses a CRT "light gun" like old Nintendo; 2) Wii uses the sensor bar, so also not a "light gun". – Yorik Oct 7 '15 at 18:20
  • I remember this game from atleast 6-7 years ago.. even then, it was pretty beat up, at the arcade. I dont recall it being on an LCD, either. I distinctly remember that CRT arqadey feel – user106385 Oct 7 '15 at 22:13

Following up on Yorik's answer, I went ahead and checked for the repair manual for this game. As mentioned, older light guns had to figure out what happened when the trigger is pulled by the way of technical trickery. In particular, most older games had to hard-code in the timing of light boxes (in relation to a CRT) to figure out if a hit was made, and which target was hit.

Moving on from there, There's many other ways to track and trigger on-hit detection. For this version of Rambo, I've found the following PDF installation and repair manual for it. What's interesting to note is that the DX version uses a SAMSUNG 56"DLP, (Which looks to be like a micro projector, but the manual uses the term CRT often.) but the two guns can be tested and tracked in real time. Likewise, there's a warning on having similar cabinets near each other due to interference, but there's a FREQ setting to help remedy issues. (This is the first sign of the answer as Infrared emitters are not "on" all the time, but can be set to a wavelength for a sensor to pick up on.)

First up, the gun itself uses the SEGA TYPE II GUN SENSOR (JPT-2030). There's not enough information I can find about this sensor, but we know that the gun's position is tracked on the screen in testing. Looking though the rest of the manual, I find that there's a IR Hood and Senor on the bottom of the screen. There does not seem to be any other technologies (like gyroscope or cameras) in use for tracking, so I'm going to have to assume that this game uses Infrared emitters for everything. It's the same technology that's used for the Wii in just about every way. The only difference is that without a gyroscope, the gun can only detect if it sees the emitters or not. If there's no sign of the emitters, then it assumes it's off-screen to reload.

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    That clears things up! I was confused because I thought IR emitters, like the WIi, were very inaccurate (like my wiimote which needs constant recalibration). The gun in this game looks accurate no matter where you are, so I thought it would use a different technology. – yesman Oct 8 '15 at 4:53
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    The guns are tethered and the cabinet encourages a particular standing area. I suspect this is optimal for accuracy. I saw a manual for one of the house of the dead cabinets, and if I skimmed it correctly, they have a timing synch cable to connect cabinets, perhaps so that the IR emitters strobe out of synch (in addition to wavelength?) – Yorik Oct 8 '15 at 14:55
  • Possibly so, @Yorik. Remember, while we try to answer OPs question, the main objective is to make it a good answer for everyone. While your answer is informative, focusing too much on an explanation will promote users simplynot reading the answer in full, to begin with. I find in cases like this, your best bet is to put a "TLDR" straight to the point at the start. – user106385 Oct 8 '15 at 16:32
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    I am not concerned at all with the points. The accepted answer works. – Yorik Oct 8 '15 at 16:35

Old CRT light guns worked by blanking the screen very briefly and then the gun detects bright light. Some worked by displaying bright regions sequentially. This happened quickly enough that the user wasn't aware.

CRTs fire a beam across the screen one line at a time starting from a corner, drawing horizontally (not unlike a typewriter filling a page). The old Nintendo method was to blank the screen when you pulled the trigger and then time how long it took for the gun to see the bright line being drawn.

Devices like the Wii, the xbone, etc now use two infrared light emitters separated by a fixed distance and the "light gun"/wiimote has an optical sensor that measures the point separation between these two sources. With the perceived separation, the known fixed distance, and some extra accelerometer data, the computer can triangulate the pointer position.

Note that a non-crt screen can still use the older blank screen method, just not the scanline timing method, but I expect that the Rambo game uses the infrared method.

  • I think this spends too much effort explaining how old light guns work, where simply explaining new light guns would suffice – user106385 Oct 7 '15 at 22:14
  • Fair enough. The OP didn't (appear to) understand either type (witness the comment thread re: the wii) so, background is important. – Yorik Oct 8 '15 at 14:51

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