NES Zapper vs LCD T.V. Any hope?

[vdub_bobby]

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.

The light guns are the same, it's just a different programming method.

 

But you're right, Duck Hunt uses a much easier (to program) method to see whether or not you have a hit, it just reads one target at a time.

 

This could work on a LCD TV, at least I assume it could. But this programming technique is worthless for more than just a very few onscreen targets, since the screen would flash for too long every time you pulled the trigger.

Edited November 13, 2009 by vdub_bobby

[Seob]

Look at this patent:

Recent advances in television and computer monitors that use LCD flat panel and plasma display systems have made current Cathode Ray Tube (CRT) display light guns obsolete. Past light guns and pen lights relied on the detection of a single horizontal and vertical retrace to detect a shoot position in X and Y coordinates. New display systems such as LCD and Plasma displays do not use a consistent horizontal and vertical retrace pulse as required by current light guns or light pens.

 

A CRT comprises a large vacuum glass tube in which a static charge is applied to the front of the display and electrons are released by an electron gun in the back of the tube. The electrons are attracted to the charge at the front of the tubes. When the attracted electrons strike the phosphorous coating on the front inside of the tube, the phosphorous glows which produces visual color. The electronic pulse is generated based on the modulated alternating current from the power supply. Typical North American power supply uses 60 hertz alternating electrical current. CRT displays use this 60 hertz alternating current to generate a saw tooth electronic pulse that in turn controls the timed release of electrons from the electron gun.

 

The electronic circuit in a CRT display system that generates the saw tooth pulse is called a fly-back transformer. The fly back transformer generates a saw tooth voltage increase that in turn increases or decreases the strength of an electro-magnet. The increasing strength of the electro-magnet pulls the electron beam across a horizontal scan line that in turn produces a visual line across the CRT display. A horizontal pulse, generated by the fly back transformer, causes the voltage to drop and in turn causes the electro-magnetic strength to decrease which in turn causes the horizontal scan to start at the beginning of the line again. Each time a line is drawn horizontally, a similar process pulls the electron beam down one line that causes repeated horizontal scan lines to travel across and down the front of the CRT display. A vertical retrace pulse at the bottom-end causes the scan to start at the top-left corner of the display for a next frame.

lightgun patent

[Darkhog]

I have an idea how to make custom Zapper which might work on LCD. As it's concept is different than original one it should work and if done correctly without recoding zapper games. Don't have enough skills nor tools to do this myself though.

 

Now we have easy access to cheap and small video cameras. Every cellphone has one. Also we have easily programmable controllers like Arduino and clever face/object detection software. So what if we would put it together? The trigger sends signal like every normal Zapper would do. Then in small delays camera inside of zapper take photo and detection software on arduino board looks for white space on screen (photo timing must be in sync with displaying object frames) If it finds it in frame center, i.e. you pointing at object in duckhunt or other game, it'll send "Hit!" signal, otherwise it will send "Miss" one. All signals send through cable to nes port will be zapper-complaint so games won't need recode. The only difference is detection method.

[Reaperman]

But you're right, Duck Hunt uses a much easier (to program) method to see whether or not you have a hit, it just reads one target at a time. This could work on a LCD TV, at least I assume it could. But this programming technique is worthless for more than just a very few onscreen targets, since the screen would flash for too long every time you pulled the trigger.

I've always wondered about creating a new NES zapper with a variable delay, that calculated its delay on the first trigger pull (by sensing the screen flash) and then repeating it--flashing the screen, waiting for the calibrated delay period, and then sensing for targets. No idea how well that would interact with software though.

[Reaperman]

^ Or is the timing handled by the software in such a way that the extra delay would break the game?

 

Maybe I'm thinking too hard about this one.

[spitman]

The NES Zapper senses light only, no scanlines are needed. I have a 56" Samsung DLP TV and the Zapper partially works (DLP TV's have a much faster response time than LCD), it works for about 3 out of 5 trigger presses. The 2 that is misses is because the screen does not go black during them. Most of the time it does go black but some times it fails to go black and I only see a slight flicker across the screen.

 

If I could figure out how to make the screen flash properly then my zapper would work 100% on my DLP TV. If I run Duck Hunt (or other game) on an emulator on a Wii then the screen flashes perfectly every time but of course I can't play using the zapper but at least the screen flashing works 100%.

 

Not sure why the NES fails to produce a stable signal when it comes to this... I've tried hooking my NES to another device that makes it come over component video (like my Wii does) but I have still the same results (misses 2 out of 5 flashes). I also tried several clone NES systems but the results are the same every time. I figure it must have something to do with the way the TV processes the signal but I've turned off every type of filter on the TV and it doesn't help at all.. why does it process it correctly coming out of the Wii but not the NES? the resolution maybe?

[godslabrat]

I just use the Video Out port on my TV and patch it to an old CRT that I have just for Zapper and ROB. Crude, but effective.

[Reaperman]

I know it's not NES gun related, but I've been wondering about Action Max (and I'm aware that I am probably the only one who as ever wondered about this).

 

It's got a sensor which hangs over a flashing dot, and it doesn't produce a video signal at all--only reads. When the gun hits a dot that's in sync with the base dot, the score increases, when it hits an out of sync dot (a friendly) score decreases. Since the lag is even between the gun and sensor, I can't think of any reason why this wouldn't work on a modern TV unless there is maybe a brightness issue. I'd try, but I'm a projector user, so I'm totally out of it anyway.

 

Essentially I'm wondering if Action Max could possibly be the oldest game console to support full HD video. If so, maybe it needs a little upgrade.

Edited October 4, 2012 by Reaperman

[shadow460]

The NES Zapper senses light only, no scanlines are needed. I have a 56" Samsung DLP TV and the Zapper partially works (DLP TV's have a much faster response time than LCD), it works for about 3 out of 5 trigger presses. The 2 that is misses is because the screen does not go black during them. Most of the time it does go black but some times it fails to go black and I only see a slight flicker across the screen.

 

If I could figure out how to make the screen flash properly then my zapper would work 100% on my DLP TV. If I run Duck Hunt (or other game) on an emulator on a Wii then the screen flashes perfectly every time but of course I can't play using the zapper but at least the screen flashing works 100%.

 

Not sure why the NES fails to produce a stable signal when it comes to this... I've tried hooking my NES to another device that makes it come over component video (like my Wii does) but I have still the same results (misses 2 out of 5 flashes). I also tried several clone NES systems but the results are the same every time. I figure it must have something to do with the way the TV processes the signal but I've turned off every type of filter on the TV and it doesn't help at all.. why does it process it correctly coming out of the Wii but not the NES? the resolution maybe?

From what I've read, the Zapper looks for certain sprites to appear on screen. Those sprites appear for a single frame when the trigger is pulled, and if the Zapper "sees" one, you score a hit. This might allow it to work on any type of TV. Other light guns use cathode ray timing to determine where the shot was placed.

 

With the Zapper, it's just a matter of making sure your TV isn't dropping any frames that the NES produces. If it displays them all, the Zapper should work correctly, but it will be one of the few light guns that does and it might not work with every Zapper game.

[spitman]

From what I've read, the Zapper looks for certain sprites to appear on screen. Those sprites appear for a single frame when the trigger is pulled, and if the Zapper "sees" one, you score a hit. This might allow it to work on any type of TV. Other light guns use cathode ray timing to determine where the shot was placed.

 

With the Zapper, it's just a matter of making sure your TV isn't dropping any frames that the NES produces. If it displays them all, the Zapper should work correctly, but it will be one of the few light guns that does and it might not work with every Zapper game.

 

Right... but how can I get the game/TV to quti dropping some of the frames? some times it doesn't flash the screen at all.. I just see a little black like go across the middle of the screen. There has to be something I can use to stabilize the signal... the flashes work 100% of the time when coming from the same games when running on an emulator on the Wii. I assume it's because the Wii is outputting 480 resolution and the NES is 240 (or whatever), maybe the converter I was testing with didn't actually upscale the resolution when converting to component video....

[Andromeda Stardust]

There are two problems at work here. First is lag. The CRT screen instantly updates the picture as the composite or RF signal is streamed to the TV. On an LCD, the entire frame is stored into a screen buffer, which is then used to refresh the entire panel once the data is scaled and processed. At a bare minimum, this adds 16.67ms (1/60 sec) of lag, plus an additional length of time required for scaling the image to fit the pixel array, which varies per TV set. Generally, on a good TV or gaming monitor, this frame delay occurs so rapidly that it escapes human perception. Second, the electron beam that scans across the CRT screen is strobed at 60Hz, so the instantaneous flash of light is at least an order of magnitude brighter than an LCD, which keeps the pixel illuminated for the entire duration of the frame.

 

When you pull the trigger to shoot at the duck, the NES blacks out the entire screen on the following frame. Then the following frame, a white box is illuminated where the location of the duck is. If there are more targets onscreen, each target draws a white box on successive frames.

 

As an example, you pull the trigger to fire at the duck.

 

Frame 0: pulls trigger (no hit detection)

Frame 1: blacked out screen

Frame 2: white rectangle for Duck #1

Frame 3: white rectangle for duck #2 and so on if there are subsequent objects on screen.

 

There is no scanline counting or detailed timing involved with hit detection. That may be possible, but would likely prove too difficult to program. During the screen draw, the Zapper sends a signal if it detects light. If a signal is detected, there is a flag bit on the zapper pin. When the screen draw is finished, the NES tests for this flag, and if it is set, a hit is detected. Pointing the Zapper at a light bulb rarely works with Duck Hunt because if a "hit" is detected on the first frame, the user is cheating (ie lightbulb) and this counts as a miss. Frame 2 is the first duck, so "1- miss", "2- hit" counts as a hit for Duck #1. Likewise, "1- miss" "2- miss" "3- hit" counts as a hit for the second duck in "two ducks" mode. Pointing at a light bulb would yield "1- hit" "2- hit" "3-hit" and the game logic detects this as cheating and counts it as a miss. Other games developed by third parties may not check for the light bulb cheat, but I know for a fact the light bulb cheat does not work for duck hunt.

 

Because all HDTVs exhibit some amount of frame lag, the Zapper cannot anticipate this and the game will almost always return a "miss." Even homebrew games cannot anticipate this effect because the amount of lag is unknown as it varies from one HDTV to the next. Furthermore, the Zapper is designed to detect the high-intensity strobe pulse of a CRT screen and is likely not sensitive enough to pick up the relatively dimmer flicker-free LCD backlight. I hope that helps explain how the zapper works. Go to a thrift store and buy a cheap used CRT. Zapper games can be addictive and are a lot of fun!

[spitman]

 

Because all HDTVs exhibit some amount of frame lag, the Zapper cannot anticipate this and the game will almost always return a "miss." Even homebrew games cannot anticipate this effect because the amount of lag is unknown as it varies from one HDTV to the next. Furthermore, the Zapper is designed to detect the high-intensity strobe pulse of a CRT screen and is likely not sensitive enough to pick up the relatively dimmer flicker-free LCD backlight. I hope that helps explain how the zapper works. Go to a thrift store and buy a cheap used CRT. Zapper games can be addictive and are a lot of fun!

 

I'm not experiencing any lag problems on my DLP TV, the refresh rate is much higher than any LCD TV. The only time it misses a shot is when the screen fails to display the black frame. Sometimes it will display the frame properly a dozen times and the shooting works perfectly and then the next trigger press will fail to switch the screen to black.

 

I've tried it on my LCD TVs and there the black frame is displayed 100% of the time but I can never hit anything because of the noticible lag.

 

I'm just trying to fix the frames being displayed with my DLP because lag isn't an issue there. Maybe using an upconverter will stop the TV from missing frames...

[spitman]

The NES zapper even works on LCD with an upscaler

[The Dord]

The NES zapper even works on LCD with an upscaler http://www.youtube.com/watch?v=06cd5y5l1Ns

 

That's a CRT, hombre.

[spitman]

Could be but the same solution applies, having an upscaler with 5ms or less will make it work on HD regardless of it being LCD or whatever...

[0078265317]

Could be but the same solution applies, having an upscaler with 5ms or less will make it work on HD regardless of it being LCD or whatever...

 

That is what I've always thought. Should be possible.

[Satoshi Matrix]

I wonder if it's possible to design a "homebrew" Zapper that uses a sensitive enough light sensor and some way of adjusting for lag, while a dile or something.

[0078265317]

Well if you homebrew on wii the fce ultra gx nes emulator has zapper support. Or fce ultra for gamecube but I can't figure out how to do it on gamecube. Saw a youtube that shows fce working on cube with action replay. But not sure how he did it.

[Csonicgo]

Not to burst bubbles, but my LED TV has a "low latency game mode" which works with the zapper.

[0078265317]

Not to burst bubbles, but my LED TV has a "low latency game mode" which works with the zapper.

 

WOW, finally a real answer. Which model is that. Name and exact number please.

[Csonicgo]

WOW, finally a real answer. Which model is that. Name and exact number please.

 

the samsung LED TV, I'll find the serial number. it has a game mode and a contrast mode that matches exactly what my CRT looked like.

 

PROTIP! RF signal and Composite signal is differently interpreted on mine! (note to self, get an atari composite mod or a good VCR)

[Greg2600]

If that LED TV does work, it will likely only work on the NES Zapper. Later zappers use full screen line by line redraw which HDTV's do not do.

[0078265317]

Any luck on finding the model number of the tv? And in the mean tine how many inches is it?? The one we have is "Sony KDL-55NX810".

[0078265317]

I found the answer. Works with a strobe light.

 

http://www.youtube.com/watch?v=rKX9WXRKYGo

[0078265317]

Wow I just found out my hdtv works. Well kinda anyway. I have a coby 18.5" hdtv flat not curved. And I put in "super mario brothers/duck hunt/track meet" cart and when I click the gun I can't start the game. But it let me switch between a,b, and c when I use the gun. And the black rectangles draw when shooting ducks even though I never hit anything.

 

Downstairs on my 65 inch tv the gun doesn't work period. Even to switch between a, b, and c. And to test I made the whole bedroom dark and the gun still worked on my 18.5" tv. Weird. I can't shoot ducks but it lets me switch between a,b, and c as if the gun was working.