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Optical Guns question
u_rebelscum:
(BTW, it looks like actlabs lightguns work pretty much the same as the arcade games. The major difference is the box that gets plugged in the video output. So look at how the actlab guns work for more details.)
--- Quote from: shadowdrak on August 23, 2004, 03:43:44 pm ---ok. so the optical signal is timed based on which pixel it is pointing at. The data file seems kind of vague. I would assume that the gun's PCB can sense the refresh rate(if not where does it get the sync?).
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Easy for the arcade gun: from seeing the screen being drawn.
When the optical sensor sees the up-spike of brightness of the beam drawing the new line, it sends the signal. (Since a white screen has the biggest spike, it's the easiest for the gun to see, so that's why happs suggests the arcade draw the screen white at trigger pull: for a more reliable seeing of the spike.)
It's the arcade PCB that needs to know the frequency to calculate the location. And since it's the source of the video signal, it knows the frequency.
--- Quote ---But per my understanding of this I conclude it would require:
A PCB to decode the tracking info and accept trigger signals. the board would receive the trigger, optionally flash the screen, then pass the tracking info on to the computer as a mouse click at the co-ordinates. I guess it could also have an adjustable auto repeat interval until the trigger debounces(but that wouldn't be in the first prototype).
My understanding is still lacking on the timing of the optical signal. I would probably have to buy one to mess with it. But I still run into the problem of not having any data analysis tools at my disposal. If I had defined specs, I could probably design a circuit for it, but that seems like it might be impossible unless we could convince someone to "take one for the team" and buy one to analyze it. That would be a lot to ask of relative strangers. Any takers though?
Would I be right in the assumption that the data rate on all standard Pc buses would be too slow to write an acurate virtual waveform analyzer for a computer? Cause if it is possible, I would personally offer to waste my time to try to hack one together.
I guess I could try to talk to Happ to get some more specific answers about their output signals. Are the tech support ppl that knowlegable anyway?
If I made a device it would probably be a serial interface so I hopefully wouldn't have to use eeproms -- might not be able to avoid this :-\
I will try to post updates to the situation, I was hoping this would have any easy solution.
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Since the actlab and the arcade guns work so similarly, with the black box that comes with actlabs guns doing what the arcade boards did, I'd suggest checking out what's in the black box that comes with the actlabs gun.
AFAIK, that black box:
a) gets the vertical and horizontal refresh rates from the video signal (and probably calibration, too)
b) intersepts the video signal and sends a pure, too bright, white signal starting from the next new screen after the trigger is pulled
c) takes the time it takes from the start of the new screen until the optical signal from the gun comes and
d) calculates the location
e) using the values from the calibration
f) and sends it USB mouse style to the computer.
That's all the board you're trying to make needs to do, except for arcade level results, you want to calculate the location even if the trigger isn't pulled (ie: add real time tracking).
--- Quote ---Might be easier to hack a console gun to work on a pc. Do they have better accuracy than act labs guns?
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Other way around. The actlab guns have the highest accuracy* of consumer lightguns, ATM. If an HD TV lightgun comes out, then the actlabs might have competion.
*(Assuming you calibrate the actlab gun correctly, and the video exactly fills the screen.)
Actlabs might have a higher accuracy than the arcade guns, too. Due to that the actlabs can work at 150 Hz refresh rate, while arcade monitors run at ~32 Hz, plus the higher resolution of PCs than arcades, it easily has a higher precision. Whether the higher precision comes out as higher accuracy needs to be tested.
mairsil:
--- Quote from: u_rebelscum on August 24, 2004, 01:55:53 am ---Other way around. The actlab guns have the highest accuracy* of consumer lightguns, ATM. If an HD TV lightgun comes out, then the actlabs might have competion.
*(Assuming you calibrate the actlab gun correctly, and the video exactly fills the screen.)
Actlabs might have a higher accuracy than the arcade guns, too. Due to that the actlabs can work at 150 Hz refresh rate, while arcade monitors run at ~32 Hz, plus the higher resolution of PCs than arcades, it easily has a higher precision. Whether the higher precision comes out as higher accuracy needs to be tested.
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On paper, the ActLabs gun may have a higher accuracy than any other gun, but it practice it seems that a lot of people (myself included) are not happy with the accuracy (possibly related to issues with calibration). Personally, I would rather have a real Happs gun.
On a side note, the Pelican Silent Scope Rifle supports HDTV's. It even works on some RPTV's as well.
shadowdrak:
I don't quite understand why calibration is necessary. Forgive me if this sounds dumb.
My brain tells me this:
If the control pcb can read the VGA signal it has horizontal and vertical sync, resolution, etc.
So why wouldn't it be enough to know such things. you can count the lines down, by dividing the time by the horizontal retrace interval, correct?
the pixel on that line would be: (time to pulse)mod(retrace interval)*(horizontal resolution)/(retrace interval)
I guess you could replace the mod part with (time to pulse)-(horizontal lines)*(retrace interval) as it might save time (i dunno really)
as long as you sync the timer to the beginning of the frame, it should have no problem finding the pixel as long as you know the resolution and the proper refresh rates.
Act labs doesn't say why you need to calibrate, only that you do. I also found nothing on google(maybe I am a sucky searcher).
You have been most enlightening up to this point, and I promise this is the last question. ;D
u_rebelscum:
--- Quote from: mairsil on August 24, 2004, 02:19:56 am ---
--- Quote from: u_rebelscum on August 24, 2004, 01:55:53 am ---Other way around. The actlab guns have the highest accuracy* of consumer lightguns, ATM. If an HD TV lightgun comes out, then the actlabs might have competion.
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...the Pelican Silent Scope Rifle supports HDTV's. It even works on some RPTV's as well.
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Pelican Silent Scope Rifle is a consumer gun? ...Googling...
Found a couple pre-release paper hype-views, a more realist reveiw saying it's not very good, and a game / gun reveiw that likes it but notes some problems.
Pluses:
tracks real time
riffle or shotgun
HD TV
Minuses:
Xbox, not PC
glowing green
neutrales:
seems to want a screen flash
I wonder how this one (and other xbox guns) works (the timing issues, ect)?
shadowdrak:
I think I am going to try to figure out a theoretical circuit to do what i think needs to be done. If i can come up with something I am pretty confident about, I will buy one of the 45 happ guns and mess around. I was reading my previous post and i thought of something. Does the calibration correct for the photodiode alignment -- depending on the angle it could get pretty far away from the right place. It tells the software that this pixel represtents a corner hit then offsets it maybe. Still a bit confused... am i too far off?