NES Zapper vs LCD T.V. Any hope?

[oldgames]

Hi,

 

I have a someone who bought an NES from me and is using it with an newer LCD T.V. Everything works except the zapper. I've heard that the zapper won't register on an LCD T.V. Can anyone confirm this and if so, is there any aftermarket zapper replacement that will work?

 

TIA,

 

Dave

[+save2600]

Hi,

 

I have a someone who bought an NES from me and is using it with an newer LCD T.V. Everything works except the zapper. I've heard that the zapper won't register on an LCD T.V. Can anyone confirm this and if so, is there any aftermarket zapper replacement that will work?

 

TIA,

 

Dave

 

I've used various light guns from various systems and have never had luck playing them on LCD's or Plasma televisions. Atari XE gun, Best Electronics gun AND a Philips CDi gun... they either did not work at all or were not accurate enough to actually play the game.

[+remowilliams]

I've heard that the zapper won't register on an LCD T.V.

It will not work on an LCD, plasma, DLP, etc. etc. You need a standard def CRT tube TV for the zapper to work.

 

 

is there any aftermarket zapper replacement that will work?

No, there is not.

[SoulBlazer]

Not that I know, but what about taking a 'modern' light gun, like the one available for the XBox or Wii, and seeing if a adapter can be made for it to plug into a NES?

 

I mean, I'm asusming these 'modern' light guns will work on a LCD since they are so common these days. That would be pretty stupid to release a, say, House of the Dead game and only have a light gun support a small fraction of the TV's out there.

[Rev. Rob]

Not that I know, but what about taking a 'modern' light gun, like the one available for the XBox or Wii, and seeing if a adapter can be made for it to plug into a NES?

 

 

Those aren't light guns.

[desiv]

I had a weird thought that I'll try when I can move some things around.

 

I have a 3DO and recently got a light gun. Worked on my little TV. We're moving, so I moved the 3DO over and plugged it into the LCD.

 

Yep, no light gun (of course)..

 

I just bought an adapter that will take composite/s-video and output it to a computer monitor.

(No, I'm not going to ask if it will work with an LCD monitor! :-) )

 

I have my CRT monitor hooked up to it. I've used it for the C64 and Amiga and it works.

I'll have to hook up the 3DO and see if that works, or will the conversion break it somehow???

 

desiv

[Jess Ragan]

If Nintendo were nice, or smart, or any combination thereof, they would release Virtual Console games for the Wii that let you play games like Duck Hunt with the Wiimote. It's designed for these games! Pointing is about the only type of input it can do well without the Wiimote Plus add-on! Yeesh.

[SoulBlazer]

See, my lack of info on this is showing. Now it's making me look like a idiot.

 

Okay, not having any of those guns and never having played a gun game since the NES days -- if what is out now are not light guns, what are they? Couldn't they be adapted for a NES?

[shadow460]

I had a weird thought that I'll try when I can move some things around.

 

I have a 3DO and recently got a light gun. Worked on my little TV. We're moving, so I moved the 3DO over and plugged it into the LCD.

 

Yep, no light gun (of course)..

 

I just bought an adapter that will take composite/s-video and output it to a computer monitor.

(No, I'm not going to ask if it will work with an LCD monitor! :-) )

 

I have my CRT monitor hooked up to it. I've used it for the C64 and Amiga and it works.

I'll have to hook up the 3DO and see if that works, or will the conversion break it somehow???

 

desiv

I don't think it'll work. One, a computer monitor's refresh rate is different from your TV. Two, the signal from the monitor is probably going to be progressive scan, not interlaced like your old TV. If it works, it won't be accurate.

 

Best thing is to buy a TV from a thrift shop and use that.

[desiv]

I have a 3DO and recently got a light gun. Worked on my little TV.

I don't think it'll work. One, a computer monitor's refresh rate is different from your TV. Two, the signal from the monitor is probably going to be progressive scan, not interlaced like your old TV. If it works, it won't be accurate.

 

Best thing is to buy a TV from a thrift shop and use that.

 

I have a little TV already, this exercise is just to try it for fun; just to see if it works.

 

desiv

[oldgames]

Thanks for the info, everyone. I figured this was the case, but I wanted to be sure. I'll pass this along to the person who bought the system. Maybe they've got a conventional T.V. they could use for the NES.

 

Dave

[Keatah]

LCD's and Plasmas don't have a beam that scans the screen, old light guns need this to work.

[Herbarius]

As this thread seams to be resolved, I would like to post a more general question about light guns.

 

Can you have a game with multiple targets on screen at once? If so, how can the system know, which of those you shot? As far as I understand the lightgun only registers light=hit, dark=miss?

[desiv]

As this thread seams to be resolved, I would like to post a more general question about light guns.

 

Can you have a game with multiple targets on screen at once? If so, how can the system know, which of those you shot? As far as I understand the lightgun only registers light=hit, dark=miss?

 

This page has all the information:

http://en.wikipedia.org/wiki/Light_gun

 

And I still don't understand most of it. :-)

 

I get the old school method, screen goes black except for a white spot the sensor should pick up. I know this because we had such an OLD system and my brother would get high scores by aiming the gun at a lightbulb. :-(

 

But the CRT methods I'm still a bit foggy on as far as when it blanks (if it still does) and what is lit and being sensed?

 

desiv

[Herbarius]

As this thread seams to be resolved, I would like to post a more general question about light guns.

 

Can you have a game with multiple targets on screen at once? If so, how can the system know, which of those you shot? As far as I understand the lightgun only registers light=hit, dark=miss?

 

This page has all the information:

http://en.wikipedia.org/wiki/Light_gun

 

And I still don't understand most of it. :-)

 

I get the old school method, screen goes black except for a white spot the sensor should pick up. I know this because we had such an OLD system and my brother would get high scores by aiming the gun at a lightbulb. :-(

 

But the CRT methods I'm still a bit foggy on as far as when it blanks (if it still does) and what is lit and being sensed?

 

desiv

 

 

Aaah, yes, the infamous lightbulb trick.

 

I read the article, and it explains it for the NES Zapper:

when it blanks the TV and lights up the positions of the targets, it doesn't light them all up at once, but one after the other... It's so fast, you don't notice it, in fact you barely even notice that the screen flashes blank at all. But not too fast for the CPU it will detect which target you shot depending on at what time it recieved light.

 

So, now as far as I can judge it, this would mean, at least the NES Zapper should even work with LCD screens? It is made clear why some other guns work with LCD screens, those that use Cathode ray timing. However, it seems the NES uses full frames, so the only reason I could think of why it won't work with LCDs is because the light isn't "strong" enough...

 

Maybe someone who has a NES Zapper and an LCD TV could try this: Make your room as dark as possible, and also turn the brightness of the TV screen up to maximum. Yes, it propably looks horrible, but it's just to try it out ^^ (note your previous setting, so you can return to it later without getting confused) Then try a light gun game, but stay close to the screen, maybe 1 meter between the tip of the Zapper and the screen... if this doesn't work, move a little bit closer and repeat...

 

It really should work, even if it works badly, shouldn't it?

[Video]

I've often wondered myself. People tell me the system is "counting scanlines" or some such....bullshit. If that was the case, the guns wouldn't work if you just pointed it at a light bulb, as there are simply no "scanlines" in a lightbulb (I know this works with at least Duckhunt, though that shows a max of 2 players on screen....and may not be indicative of all NES games)

 

I still hold that it's a timing issue, which should be technically fixable, and could easily be done on say, the VC, but honestly, I see no reasone, especially a newer LCD with a 8 or even 4 MS refresh rate couldn't do it, as long as it's in sync with the system. But just playing the games, I can feel the lag on most TV's, so I don't know, a lot of modern consoles have lag built in to handle the problems.

 

Anyhow, yeah, the old light guns, 8 bit, detect light, nothing more. Heck, many of the guns don't even work with old style CRT's as the detection diodes are simply wearing out...but get a working gun to start with, and a bright enough screen witha high enough refresh, it should work fine.

 

16 bit on up do something different, at least, I remember the SNES/Genesis POS guns using some sort of light bar like the Wii, I have never had a working setup of either of these, but I think if it worked more or less the same, as they are wireless guns, it would be easy to fix replacing the IR sensors with RF sensors (then you can actually add lag (or subtract it ast hte case may be) )

 

Newer stuff, Wii, X-box, whatever, are actually using low grade cameras and just doing a comparison of what they are looking at, a x shaped blob was shot at, so the X shaped object on the screen is what the system says you hit.

[Shawn]

The act labs USB light gun works with monitors so I guess with a retarded amount of work you could maybe get one of those to work with your NES.

[+remowilliams]

Newer stuff, Wii, X-box, whatever, are actually using low grade cameras and just doing a comparison of what they are looking at, a x shaped blob was shot at, so the X shaped object on the screen is what the system says you hit.

Where on earth are you getting your 'information' from? The Wii uses IR sensors and an IR emitter bar, and the PS3 Guncon also uses an IR setup.

[RevEng]

...the old light guns, 8 bit, detect light, nothing more.

Correction: the nes zapper detected only light.

 

Other lightguns and lightpens of the era dealt with scanline positioning just fine.

 

The big N used the light/dark method to lower the cost of the gun.

[gdement]

I see no reasone, especially a newer LCD with a 8 or even 4 MS refresh rate couldn't do it, as long as it's in sync with the system. But just playing the games, I can feel the lag on most TV's, so I don't know, a lot of modern consoles have lag built in to handle the problems.

Every LCD has input lag (not the same as refresh rate), so it wouldn't work without reprogramming the game to be aware of that issue.

At minimum, there's the lag of waiting for the entire frame to be transmitted to the screen before it can be displayed. This means at least the top portion of the screen will be almost 1 frame behind, even in the best possible case.

In that best case, some NES games might be tolerant enough to work.

Anyway, I've only heard of very few LCDs that might be this fast. Nearly all of them have more significant lag.

 

I think new games could be programmed with a calibration screen, which would measure the lag of your display and keep it in mind during gameplay. This would require the lag to be consistent, and it might not be with some displays. They'd also be forced to use the light/dark method obviously.

 

 

The big N used the light/dark method to lower the cost of the gun.

Is it really any different than other light guns? I thought the difference is just in the programming. I don't see why a NES game couldn't be programmed to use scanline timing. It apparently wasn't convenient though, probably due to the way that system handles it's graphics.

[RevEng]

The big N used the light/dark method to lower the cost of the gun.

Is it really any different than other light guns? I thought the difference is just in the programming. I don't see why a NES game couldn't be programmed to use scanline timing. It apparently wasn't convenient though, probably due to the way that system handles it's graphics.

The zapper reports back light/dark to the console every 1/30th of a second. This relatively slow rate means the zapper can be a dumb device and let console can deal with the timing issues itself. It also means you don't need a photoreceptor that's anywhere near as fast or sensitive.

 

I'd guess that most electron-beam based guns have additional circuitry to assist with the horizontal position/timing as well. If they were dumb devices you're looking at about 80000/s worth of light samples to transfer and process. (assuming 80 pixel wide resolution)

[gdement]

The zapper reports back light/dark to the console every 1/30th of a second. This relatively slow rate means the zapper can be a dumb device and let console can deal with the timing issues itself. It also means you don't need a photoreceptor that's anywhere near as fast or sensitive.

Interesting. So if it only reacts in 1/30 sec intervals, then I guess scan timing would be impossible on the zapper.

 

I'd guess that most electron-beam based guns have additional circuitry to assist with the horizontal position/timing as well. If they were dumb devices you're looking at about 80000/s worth of light samples to transfer and process. (assuming 80 pixel wide resolution)

 

Using the 7800 as an example (just because I'm more familiar with it), there's 80 6502 clock cycles in the visible range of each scanline. (going by the "7800 software guide" PDF)

 

I got curious so I typed some untested, probably broken pseudocode for polling a light gun (see below). I don't actually know how the 7800 gun is programmed, I'm just guessing here.

It looks like it could be sampled at least 5 times per scanline, or 6 if you don't mind them being unevenly spaced. The uneven spacing is consistent so the code can still resolve it accurately.

 

Either way, 5-6 samples isn't very many. However, you could stagger the starting point on each scanline to get more useful resolution.

That would give 80-96 horizontal positions checked within a vertical tolerance of 16 scanlines, or 40-48 per 8 scanlines, whatever. That might be reasonable, but I don't know if they really programmed anything that way.

 

You might be right about the gun having assisting circuitry. I didn't think so, but the 6502 isn't as fast at this as I thought it would be.

 

 

<Maria is disabled while scanning>
<set scanline counter to 0>

NextLine:
ldx #5      ;sample counter.  We can do up to 6 samples per scanline
<use scanline counter to calculate an appropriate stagger value for this line>
<use WSYNC to sync with start of scanline>
<use nop's or some other method to stagger the start of sampling>

ScanLoop:
lda   GUNSIGNAL           ;6  ;(RIOT access will slow it down by 50%) I'll imagine it returns 0/1 depending on result
beq   SAWLIGHT            ;2 (when not taken)
dex                       ;2
                         ;unroll the loop here to squeeze in 6 samples instead of 5
lda   GUNSIGNAL           ;6
beq   SAWLIGHT            ;2
dex                       ;2
bpl   ScanLoop            ;3 (taken until done with sampling)
                         ;23 cycles per 2 samples  (we have 80 available after WSYNC)

<increment scanline counter>
bne NextLine  (always taken)


SawLight:
<decode the counter and decide where we hit the screen, etc>
<X tells us which sample on the current scanline was a hit, and the scanline counter tells us what line>

 

Unrolling the loop above does mean the samples aren't evenly spaced. To make them even, roll it back up and get 5 samples instead of 6.

Edited November 13, 2009 by gdement

[vdub_bobby]

-All light guns work the same way AFAIK.

-Every light gun just senses light or dark, the light gun itself doesn't count scanlines or any such nonsense.

-All the magic is done in programming: you poll the light gun repeatedly while drawing the screen - whenever the light gun reports a hit, whatever you are currently drawing is hit. Or rather, whatever is at the position you are drawing is a hit.

-It's the same basic concept as reading a paddle (2600) except you need finer resolution.

-You flash the screen to make sure the light gun picks up something.

-You can poll the NES controllers, including the Zapper, as often as you want, just like on any other system, AFAIK.

 

-For most light gun games, they are designed so don't need pixel-accuracy, which is almost impossible anyway since you can't poll the gun fast enough.

 

The reason they don't work on a modern TV is that the entire screen is refreshed at the same time, so a hit is detected immediately - like you are aiming at the upper left corner. At least, that's how I assume it would work.

[RevEng]

-All light guns work the same way AFAIK.

-Every light gun just senses light or dark, the light gun itself doesn't count scanlines or any such nonsense.

Check out the wikipedia entry on light guns. Yes all light guns sense light or dark, but one kind ignores what the game outputs on the screen and sees the relatively brighter (but brief!) electron beam as it passes, the other kind operates as you describe. Specifically read up on "Sequential targets" vs "Cathode ray timing". More good information on how fast the Cathode Ray Timing method needs to operate at is included in the "Combined Method" section.

 

-It's the same basic concept as reading a paddle (2600) except you need finer resolution.

The irony here is that the 2600 doesn't look at raw position of the paddle, but rather there is extra helper circuitry built intentionally into the VCS to read it, namely a (dis)charging capacitor and ADC to indirectly measure the position of the paddle.

 

@gdement: Nice work on the pseudocode. I'd guess the 7800 gun uses something similar to the paddle scheme... a capacitor that discharges in the HBLANK and charges until the time the electron beam is detected, or some variation on that. No actual reason why you couldn't extend that over multiple lines, except the resolution of the ADC would limit your horizontal resolution.

 

Just guessing, as there could be a lot of functionally equivalent schemes, but it seems the Atari way of doing things.

 

And that definitely doesn't hold for more modern Cathode Ray Timing guns, which could just have their own microcontroller that only needs to be appraised of the frame start, after which it can count cycles until it sees the electron beam pass, and report back that time (or a failure to see the beam) to the console after each frame.

Edited November 13, 2009 by RevEng

[desiv]

The reason they don't work on a modern TV is that the entire screen is refreshed at the same time, so a hit is detected immediately - like you are aiming at the upper left corner. At least, that's how I assume it would work.

 

So, how fast would an TV need to be, and could you build a piece of hardware that sends only 1 pixel (scanline? could a pixel be detected as a scanline or??) at a time to the LCD as one screen. (Would that be a re-interlacer? )

 

I can't see any way in the world, even if it was feasible, that anyone would bother doing that just to get light guns working, but..

 

desiv

Edited November 13, 2009 by desiv