LCD TVs + Light Guns

[godslabrat]

Last year, I upgraded my gaming rig to include a sweet 37" LCD HDTV.

Granted, it's not the best HD set there is, but it was the best I could afford. I

chose LCD because, to me, it offered the best deal over CRT, DLP, and Plasma. As

you can probably guess, one of my most primary concerns was how it would make my

classic games look. I'm pleased to say that the results are mostly satisfactory.

while there were a few unforseen side effects of scaling 20-year-old games

up to 1080p, I honestly wouldn't want it any other way.

 

 

That said, there is one little flaw which has kept this from being a complete

success: light gun games. The LCD set does not register with my NES Zappe,

and I'll bet good money it doesn't work with ROB. While this eliminates less

than 15 games from my list of possibilities, I'd certainly like to correct that if

possible.

 

 

It is my understanding that the light gun games don't work because the

refresh rate of an LCD monitor is still not quite what it would be for a CRT screen, and

thus the gun doesn't see the screen properly. If true, that means this TV

will never work with any Zapper games. Okay, I can live with that. However, going

forward, I'll probably be replacing this set in 5 years... are there any predicted

advancements in technology that would make future sets compatible with older light guns?

 

 

FWIW: While DLP may be an option in the future, let's assume I won't warm

up to CRT or Plasma anytime soon.

[acharris]

Hi, I think the problem is that the old light guns like a NES zapper, Saturn gun and the like is that it uses the flicker scan lines which make up a picture on a Standard Def CRT to register it's position and cause a flash to register a hit. LCD and the like TV ain't made up of scan lines today, but they are pixels. So the screen has no reference points to register via the scan lines.

 

This would also be the same if you bought a 100 Mhz CRT TV before lcd's and plasma, as 100 mhz is flicker free so the guns don't work. The only way a gun would work on a modern TV is if all light guns uese the same type system the Wii uses and use a sensor bar to register it's positions. So the problem is nothing to do with refresh rates not good enough, as a 2 ms response LCD would be no good due to the pixels making up the display

 

Hope this helps.

 

Anthony

Edited September 7, 2007 by acharris

[godslabrat]

Hi, I think the problem is that the old light guns like a NES zapper, Saturn gun and the like is that it uses the flicker scan lines which make up a picture on a Standard Def CRT to register it's position and cause a flash to register a hit. LCD and the like TV ain't made up of scan lines today, but they are pixels. So the screen has no reference points to register via the scan lines.

 

This would also be the same if you bought a 100 Mhz CRT TV before lcd's and plasma, as 100 mhz is flicker free so the guns don't work. The only way a gun would work on a modern TV is if all light guns uese the same type system the Wii uses and use a sensor bar to register it's positions. So the problem is nothing to do with refresh rates not good enough, as a 2 ms response LCD would be no good due to the pixels making up the display

 

Hope this helps.

 

Anthony

 

Well, sure, it gives me all the inconvenient facts I need. but now it looks like I'm SOL. You call that HELP?!?!

 

:-)

 

Oh well, I could always mount a basic CRT nearby. I have a feeling they'll be cheap and plentiful for the rest of my lifetime.

[MCHufnagel]

Hi, I think the problem is that the old light guns like a NES zapper, Saturn gun and the like is that it uses the flicker scan lines which make up a picture on a Standard Def CRT to register it's position and cause a flash to register a hit. LCD and the like TV ain't made up of scan lines today, but they are pixels. So the screen has no reference points to register via the scan lines.

 

This would also be the same if you bought a 100 Mhz CRT TV before lcd's and plasma, as 100 mhz is flicker free so the guns don't work. The only way a gun would work on a modern TV is if all light guns uese the same type system the Wii uses and use a sensor bar to register it's positions. So the problem is nothing to do with refresh rates not good enough, as a 2 ms response LCD would be no good due to the pixels making up the display

 

Hope this helps.

 

Anthony

 

Well, sure, it gives me all the inconvenient facts I need. but now it looks like I'm SOL. You call that HELP?!?!

 

:-)

 

Oh well, I could always mount a basic CRT nearby. I have a feeling they'll be cheap and plentiful for the rest of my lifetime.

Actually there are some PC lightguns that are compatable with LCD screens. They would work if you emulated on a PC and connected it to your television. But other than that, if you have the room look for older CRT tv's. You can even find 36" tv's pretty cheap now-a-days.

[+Stephen Moss]

This would also be the same if you bought a 100 Mhz CRT TV before lcd's and plasma,

Don't you mean 100Hz?

 

Investigating the LCD and light gun issues is on my to do list, however there are meny potential pitfalls such as...

a) AFAIK most light guns initiate a timer on the vertical sync which is then stopped when light is recieved and the resulting value provides relative position so as acharris stated any refresh rate over 50hz (Europe) or 60Hz (USA) could cause problems with reading the correct value.

b) the LCD set may be internally conveting the image so that signals transmitted as interlaced are display as progressive scan which could again cause timing issues.

c) CRTs work by firing an electon beam at phosphur on the screen, the phospher is energized by this and emits light in the form of photons (plus some x-rays), I believe that that LCD displays work by absorbing colour rather than creating it therfore the amount of unabsorbed light reflected from the screen is to low for the light guns to detect.

 

If point C is the only issue then you could try to remedy the problem by...

1) changing some of the light guns components to make it more sensitive or

2) connecting something like a high intensity white led to your light gun which shines towards your LCD set, the idea behind this is that the increased amount of light hitting the screen will result in a increased amount of reflected light thus allowing detection, however you would have to set the LED at the correct angle to ensure that any reflected light enters the light gun but this angle will differ depending on the range so once set you will have to use it a approximately the same distance from the screen every time you use it.

 

Sorry I can be more helpful than that, but until I have time to investigate this myself I have no idea which item or items mentioned above is the problem and therefore I have no definative solution.

[Hornpipe2]

Is it possible that your LCD 'lags' a little in displaying the image, so by the the time the check pattern is on the screen the gun has already stopped looking for it?

 

AFAIK LCD screens shine light through the semi-transparent medium so you can't really reflect more light off it.

[roland p]

A standaard light gun would never work with lcd. The response-time of lcd is just way too slow compared to crt.

 

I think (in theory) it would work if you have the following:

An lcd-compatibly-gun: http://www.play-asia.com/paOS-13-71-zo-49-en-70-16s7.html. This is a wii-like system with ir-leds around your tv.

 

Then you need some sort of converter. The converter should connect to the gun, and to your av and joystick output of your atari/nes/old system.

With the information of the video-signal and the position from the lcd-gun, the converter would be able to emulate a standard light gun, giving pulses to your system at the right time, based on the video-signal.

 

Roland.

[Bryan]

Light guns work by detecting the instant jump in brightness that occurs when the electron beam moves across the phosphor. If you've ever seen a wildly flickering TV/Monitor on TV, you've seen what the picture is actually doing even though our eyes don't detect it (it takes special equipment to sync up TV's with cameras so this doesn't happen).

 

With analog TV, the movement of the beam is completely controlled by the connected video device. There is a reliable time relationship between the sync signals generated by the video device and when a particular spot on the screen will go bright again. Light guns work on that principle:

 

When the spot being aimed at goes bright, save the current H and V position of the beam.

 

Digital TV's aren't reliable in this regard since they digitize incoming video information, process it, and send it out to the panel with different timing. Plus, LCD's don't generate the kind of "instant-on, slow fade" flicker that CRT's do. Instead, LCD's have a slow-on, slow off property known as response time.

 

I don't know how modern light gun technology works, but the old technology is certainly headed for extinction.

[spacecadet]

A standaard light gun would never work with lcd. The response-time of lcd is just way too slow compared to crt.

 

It has nothing to do with response times. In fact, light guns work by relying on the fact that CRT's have to blank the screen every time they refresh. LCD's don't. This is why CRT's flicker; LCD's display a solid image. It's that fact that means a standard light gun can't work with an LCD; it's because LCD tech is *better*, not worse. Light guns rely on a negative aspect of CRT tech, not a positive one. It just so happens that a positive side effect of this negative aspect of CRT tech was the creation of the light gun.

 

Not that that knowledge helps in this case.

[Uzumaki]

That reminds me, has anyone taken an Atari 2600 (unmodded and with old switch box that has 300 ohms terminals) to a local Best Buy and see how long they take to find a 40" or bigger HDTV display that works. Even if they figure out using 300 to 75 balun (or skip switchbox and use direct adapter with RCA female to F-Type male) and an RF modulator, some TV still may not like some 2600 game's quirky video timing.

[Artlover]

it's because LCD tech is *better*, not worse.

That's a matter of opinion.

[roland p]

It has nothing to do with response times. In fact, light guns work by relying on the fact that CRT's have to blank the screen every time they refresh. LCD's don't. This is why CRT's flicker; LCD's display a solid image. It's that fact that means a standard light gun can't work with an LCD; it's because LCD tech is *better*, not worse. Light guns rely on a negative aspect of CRT tech, not a positive one. It just so happens that a positive side effect of this negative aspect of CRT tech was the creation of the light gun.

 

Not that that knowledge helps in this case.

 

You do have a point, the fact that LCD's don't blank between two frames (a side effect of tft) is not going to help...

But maybe the lightgun games first send a black frame and then a white frame?

I think Bryan also hit the spot, mentioning the 'instant jump in brightness'. With LCD, this 'instant jump' is not so instant anymore and more difficult to detect.

 

I don't know how modern light gun technology works, but the old technology is certainly headed for extinction.

The wii-like technology works with a little camera that sees the infrared led's in the sensorbar. With this information, it is able to calculate the position you are ayming at.

http://www.x-arcade.com/newsletter/Wii%20Dupe.shtml

Edited September 26, 2007 by roland p

[AtticGamer]

Light gun on a LCD is only possible through sensor bar like the Wii I think.

Just get an old tv next, or use a emulator on one of your modern consoles.

[MEtalGuy66]

Heh. Well, the VBLANK is not the problem. On an atari, the light gun is not a "smart device".. It's just an "eye".. The atari knows the lightgun position on the screen because it is synced with the CRT and knows which scan line it is currently outputing. It simply watches, and when the raster beam crosses the "eye" it knows that:

 

"Hey! X number of milliseconds(horizontal pos.) after initiating output of scanline Y(vertical position), I saw the signal from the lightgun that the raster beam had crossed it's photocell"

 

I mean I could go into much deeper technical detail, but thats about the size of it..

 

And since an LCD does not even HAVE a raster scan (in the sense of a beam that scans left to right,) the two technologies are basically incompatable..

 

As an additional point of interest, It's not going to work with a DLP reverse projection TV, or a DLP or LCD based projector either..

 

It COULD conceivably work with a reverse projection TV that still uses 3 separate CRTs for Red,Green, and Blue (the old technology), but the convergence of the 3 would have to be near perfect to a tolerance of much less than one scanline. Also, most TVs that used this technology were not able to produce nearly the brightness and/or contrast ratios of standard color CRT technology.

Edited October 9, 2007 by MEtalGuy66

[Hornpipe2]

Heh. Well, the VBLANK is not the problem. On an atari, the light gun is not a "smart device".. It's just an "eye".. The atari knows the lightgun position on the screen because it is synced with the CRT and knows which scan line it is currently outputing. It simply watches, and when the raster beam crosses the "eye" it knows that:

 

"Hey! X number of milliseconds(horizontal pos.) after initiating output of scanline Y(vertical position), I saw the signal from the lightgun that the raster beam had crossed it's photocell"

 

I mean I could go into much deeper technical detail, but thats about the size of it..

Wikipedia agrees with your explanation. However it looks like an NES Zapper should still function on an LCD as it doesn't use the method you described.

Edited October 10, 2007 by Hornpipe2

[tripletopper]

I heard every TV can play old Zapper/Segascope 3D game if you don't try to upgrade the signal, but program your TV to run S-Video, Composite, or RF analog in their appropriate resolution. Every modern TV has the ability to run analogue TV for low powered stations. To PLay 2600's you must switch out of digital TV mode and switch to analogue. It seems like most of the problems arise when to try to artificially improve the image. A Sony 32 inch LED screen is meant to be a gamer's screen, and according to Sony, there is a mode which accurately preserves the 480i mod, and the left-to right scanline mode. And Sony said it's common in most TV's, not just Sony's. Their advice is if you want to optical devices like light guns and SegaScope to work, running it as close to the original as possible gives the best results. It's sort of like a PS2's when playing PS1 games: Artificially improving loadtimes or polygons increase the chance for incompatibility. If you leave it at the native resolution (or only improve games that don't rely on Optics) your optical games should work fine.

[tripletopper]

By improving the signal, I mean stuff like plugging a composite video into a DVD and outputting that through HDMI. There's a digital delay and a upgrade, one of those alone would run the video game. Both of those combined, OUCH. If you want to record a light gun game through a DVD recorder or DVR, but want to play it with no lag (I.e. the Light Gun accurtely capturing the target) , do the following:

 

1) Buy 2-3 RCA Y-Cable adapters and appropriate sex changers if you cant find an exact match, and 2 extra sets of cables.

 

2) Plug the Video and audio out into the Y adapter. Plug the other 2 RCA cables in the DVD input and the direct TV input.

 

3) Start the DVD recording (make sure it's on the right DVD input) then turn to the direct TV input and play while watching the direct feed. The DVD might be a frame or less behind, but who cares, DVD's are for replays not for the original game, which you're watching on the direct feed.

 

Unfortunately, you can't replay SegaScope 3D games because he sync is in the system, and the DVD recorder can't interact with the Master System.

[+poobah]

No.

 

Every LCD TV is frame based.

There is no horizontal scan like a CRT has.

[Keatah]

As time goes on, display technology will only get further and farther away from what the old light-sensor guns need.

[Retro Rogue]

Heh. Well, the VBLANK is not the problem. On an atari, the light gun is not a "smart device".. It's just an "eye".. The atari knows the lightgun position on the screen because it is synced with the CRT and knows which scan line it is currently outputing. It simply watches, and when the raster beam crosses the "eye" it knows that:

 

"Hey! X number of milliseconds(horizontal pos.) after initiating output of scanline Y(vertical position), I saw the signal from the lightgun that the raster beam had crossed it's photocell"

 

I mean I could go into much deeper technical detail, but thats about the size of it..

Wikipedia agrees with your explanation. However it looks like an NES Zapper should still function on an LCD as it doesn't use the method you described.

 

No, the concept of how the NES zapper and similar guns work will work on modern LCD/Plasma tv's. The actual NES zapper and games will not however. They're still synced to a raster CRT television frame rate. LCD and Plasma draw the entire frame at once - which occurs at a fast rate than a raster CRT based television display (which draws down the screen with scanlines before it completes an entire frame).

 

 

 

 

 

[0078265317]

What about this then.

 

http://www.ehow.com/how_5858711_play-duck-hunt-hdtv.html

 

[Retro Rogue]

What about this then.

 

http://www.ehow.com/...-hunt-hdtv.html

 

 

What about this then what? He clearly states in the video you need to have special equipment, i.e. external scalers and de-interlacers that work within the amount of time of time the NES expects. And not only that, but turn off (circumvent) the HD TV's own.

[0078265317]

But at least it is possible to play again. A old crt tv is going to cost a lot also (especially one in good shape).

[Retro Rogue]

But at least it is possible to play again. A old crt tv is going to cost a lot also (especially one in good shape).

 

It's not, it's a lot of specific what if's that aren't universal.

 

And CRT TV's are extremely easy to get at the local thrift shop.

Edited April 19, 2011 by wgungfu

[0078265317]

And CRT TV's are extremely easy to get at the local thrift shop.

 

Used but not brand new. That crappy used crt will break in 6 months maybe if even. And replacing the picture tubes mega expensive.