Lichtknarre: Unmodified Wii remote as a sight accurate Lightgun using 2/4 LEDs

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lilshawn:

--- Quote from: RandyT on January 04, 2023, 01:42:16 pm ---I've heard tales that a standard silicon diode, in series with a schottky diode can be enough to bring the voltage of a standard 3.7v Li-Ion down into usable range. This is based on a .6-.7v voltage drop of the silicon diode and the .3-.4 drop of the schottky. But it's not the best way to do it, as there are some possibilities for it to not work as expected and cook what you are powering. It also doesn't make a lot of sense now that very cheap and surprisingly decent regulators are easy to find.

--- End quote ---

ahh, the ol' dirty sanchez voltage regulation.

Dirty Sanchez: i want 12 volts
Car: here's 14 volts
Dirty Sanchez: here's diodes used improperly to drop that down to 12
Car: But, what about when i'm not running?!
Dirty Sanchez: not my problem.

Howard_Casto:
So I did a bit more research on the nyko wand and it's "trans-port technology" tonight after I saw an article where they mentioned that rumble could also be passed along to a nyko nunchuck. Turns out, nope it's just exposed pins like I originally thought. Three contact areas are exposed below the standard wii expansion port for A, B and ground respectively. So what about rumble? Well, nyko got sneaky.

Observe this pic of their kama controller:

See those two contacts on what would normally be part of the ground plane on the connector? Yeah that's rumble out.

Honestly, I'm not sure how useful any of this info is. The exposed A and B pins might, but to access the rumble you'd really need a nyko kama controller cable, and at that point you might as well just hack the wiimote since you'll be hacking the kama anyway. It needs documented though as all the data on these controllers that used to be one the web seems to have disappeared. I'm sure glad I've already wrote a test program that can read every wii accessory I could get my hands on so I'm not guessing on the protocols. These wands are cheap enough so I'll probably pick up at least one to see what I can find out.

RandyT:
I was finally able to spend some time doing a proper test of the "fish-eye" lens. And as long as I was making an adapter for the lens, I figured I might as well make the "Perfect Shot" more perfect for sight accurate use as well. It's quite a bit better now than stock ;)

Near as I can tell, the alignment of the lens is right on. After calibration, things track nice and straight in the center of the screen and show similar curvature distortion on both the top and bottom, so that's a good sign.

So, does it work? Well, it does...but not without a few caveats. The first one is the obvious distortion issue. The lens will completely screw up the calibration and might make it difficult to use the wizards. This is to be expected, as the lens will make the ratios look a little off. Manual calibration isn't too difficult if that's what needs to be done. If enough people use this kind of lens (and the author happens to be one of those people :) ) we may see some built-in correction at some point.

Toward the central area of the screen, I didn't notice much of an issue, if any. The cursor seemed a bit jumpy, but I'll cover that later in. As far as accuracy goes, there really isn't much drift until you get toward the edges of the screen. It's not huge, but it's likely enough to adversely affect performance for a really demanding title like Point Blank. But VC and HOTD:R seemed to play perfectly fine.

In fact, in the first scene of VC, I was able to hit 95% accuracy on the first test and where I missed I knew it was something I did. And that brings me to a serious benefit of using the lens: Distance. This add-on allowed me to be closer than half of the distance I would otherwise need to be at. If I didn't know that these games were meant to have players this close to the screen, I'd have felt like I was cheating. It makes that much of a difference. My CRT is 37" diagonal, but there is a wide, angled bezel around the tube, so it's more like 43" based on where the LEDs needed to be. Even with a screen that large, 24 to 30" seemed to be the sweet spot. I haven't tested with anything smaller, but what I have seen leads me to believe that just over a foot would be doable on a typically sized 4:3 arcade monitor.

Now for what could be the biggest issue for some, at least those who have larger screens. LED beacon brightness. There's no such thing as 100% transmissive lens, and as the size gets smaller, and the lens system gets cheaper, the more that transmission gets reduced. This means that there is a smaller zone the gun must be in to work, as too far away means not enough energy from the LEDs, but too close, and the pattern gets lost. At first, I thought it was something which might be addressed by angling the LEDs, but even positioning the muzzle directly on-axis with one of them seemed to have no effect on the ability of the system to pick it up, past a certain distance, even with the sensitivity cranked to maximum. I also noticed a bit more jitter from the cursor, likely due to the reduced brightness. I was able to effectively make use of the "bad LED" and smoothing modes to minimize a lot of this, which normally isn't necessary without the lens. I may completely remove the IR filter to see if this has any positive effect, but probably not right away.

At the end, it's a bit of a mixed bag. If absolute accuracy is important to you, you may want to skip the lens, wait for the curvature corrections in the software or maybe try an intermediate power to see if it has less distortion. But if you tend to play the standard fare and want more of a "real light gun" experience where distance is concerned, I would give it try. I didn't find it so bad that I immediately removed it, so that probably says something.

*Edit*

Did a little more testing with a cell cam and the fish-eye. I think the FE may have some even larger issues. With a regular camera, there seems to be quite a bit of internal reflection and loss of focus at the edges, both of which could be causing some major problems. I think I'm going to downshift and try out the less extreme wide-angle lens. Some simple testing has showed that this has the potential to be nearly as as good distance-wise, but with less negatives.

RandyT:
Part 2:

The standard wide-angle lens is much better. Still gets closer by an arm's length, not jittery, better accuracy than the fish-eye and no apparent issues with the ability of the system to pick up the LEDs at greater distance. It's also smaller, so that could help in some build-related situations.

There is still some curvature distortion at the corners, which will mean an occasional miss in those areas, but really not bad. With it, I was able to get through the intermediate (yellow) ladder of Point Blank with one continue and still had 3 lives left at the end. So definitely a decent option to get closer to the screen.

Howard_Casto:
This is just an idea off the top of my head but wouldn't the easiest way to implement a fix for the distortion be a distortion lookup table? I think the wiimote uses a 1024 by 1024 "image", so have a 1024 by 1024 array and with each ir coordinate look up that array coordinate to get a pre-calculated correction of where that point really is sans-distortion. I'm sure the distortion amount is documented for various lens specs and if not, it'd be possible to take two pictures on a tripod, one with an unmolested image (proboably of a grid) and then one using the clip-on lens to determine where each point in the grid lines end up after the lens.

I'm not sure how viable that method is but, in my mind, it would require the least amount of processing time, so it'd reduce lag as opposed to correcting on the fly.

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