Stickfreaks!

The Nintendo Wii is the current king of lightgun games. Particularly now that CRT TVs are dropping in popularity, it means that the WiiMote's infra-red system is supplied ready to go to developers who want to make modern light-gun games.

(For those that don't know, the older style light guns (like the G-Con/GunCon family popular on PS1 and PS2) require a CRT television so that they can match the scanline and sync to a point on the screen, which no longer works on any of the flat-panel LCD/Plasma (or forthcoming OLED/SED/etc) TVs).

One thing that many fans of Wii lightgun games have noticed is that the accuracy (particularly on large TVs) of the WiiMote leaves a lot to be desired. While not enormous, I have an 80cm (31") 4:3 TV, and even that would show signs of problems on most lightgun games. Playing one of my favourite arcade lightgun games, Ghost Squad, I found that I had problems shooting at the corners of the screen - the target would "lock up" within an inch or so of the corner, making it difficult to hit anything coming from there. Also when aiming towards the edges of the screen, the targeting would seem to overshoot the mark, causing you to regularly aim past the enemy and miss critical shots.

I made the assumption that this was to do with the position of the LEDs within the Wii's "sensor bar" (a silly name, considering it doesn't "sense" anything, as the WiiMote's IR camera does that). They seemed far too close together to accurately inform the WiiMote of where it was pointing. If you're at an arcade and happen to see a modern lightgun shooter (Ghost Squad, House Of The Dead 5, etc) you'll notice small IR LEDs all around the monitor. These are generally close to the full width of the monitor. Seeing as the Wii Sensor Bar is such a simple piece of kit, I decided to mod it.

Googling around led me to a few sites of folks who had done the same. Sadly I've since lost the bookmarks, which is a bummer as I'd love to give some credit here. But I'm certainly not the first to attempt this.

First, I grabbed a spare sensor bar from Deal Extreme. AU$9 and a week later, it arrived on my doorstep. (hooray for China and internet ordering!). It's frightening how close to the original these knockoff parts look some times. Asides from a missing Nintendo logo, you wouldn't notice the difference. I decided to purchase a second bar for two reasons: (1) in case I screwed up and destroyed the device, and (2) so that I would have something to compare and contrast the original bar to. Considering the low cost of the spare part, it wasn't a huge issue.

The original bar is 24cm long (hello to readers in the US: no, I won't be using outdated imperial measurements, and neither should you). Compare and contrast to my TV screen, which is 64cm wide.

Unscrewing and removing the sensor bar case revealse exactly how little tech there is inside the device.

The mod itself was trivial. Remove the electronics and cables and replace the 15cm wire between the IR circuits with 50cm (chosen completely arbitrarily) lengths of wire (soldering required, but it's not rocket surgery). With the wires removed, cut the housing in half neatly with a hacksaw. Reassemble when complete. The new length of the unit end-to-end is 56cm.

Back on top of the TV, and you can see the original sensor bar sitting in between the two halves of the modded bar.

Testing from within the Wii's Sensor Bar setup menu, here's what the IR camera in the WiiMote sees. Note the distance between the two white dots inside the grey box. I'm sitting on my couch roughly 220cm away from the screen.

Now we unplug the old bar, plug in the new one and compare. Again, 220cm from the screen.

So the WiiMote definitely sees a difference. What about in-game? Well, I can't really show any screenshots or videos, as it's all very subjective. However there is a noticable difference in the accuracy of the WiiMote for lightgun games. First cab off the rank was Ghost Squad, and all the criticisms I had from the top of this page are gone. I can now hit the corners accurately and without the cursor "locking" before it hits the corner. The "overshoot" problem is not gone entirely, but is definitely a fraction of what it used to be - certainly good enough for me to turn off the in-game cursor and play without it. Not only is this more like the arcade experience, but Ghost Squad in particular rewards the player with more points for doing so.

House of the Dead 2 and 3 Return (another Sega arcade title with good calibration menu) shows even more improvement. Calibration in the corners is now easy to achieve, which leads to perfect alignment. This game easily achieves the best accuracy of all the title's I've tested. Overshoot is eliminated entirely, and there's no need for the cursor at all. Even with the cursor, shots are steadier, and accuracy is fantastic.

Link's Crossbow Training shows some improvement also. In general the game suffers more cursor lag than Ghost Squad, but turning the cursor sensitivity all the way down to it's lowest setting resulted in the onscreen cursor being far more accurate to where the WiiMote was pointed, and again the "overshoot" problem became quite minimal. Other family members noted the game was easier to control as well, which means either the placebo effect on me is minimised, or we're all sharing it. :)

Considering the low cost, near-zero risk (particularly with a second sensor bar), and fantastic result, I'd recommend anyone who loves their lightgun games to try the same. To date I've purchased Ghost Squad, House of the Dead 2 and 3 Return, and Link's Crossbow Training with the offical Nintendo lightgun kit. House of the Dead Overkill is out now also, and this mod should make it that much better.

For those with really, REALLY big displays, check out what this enterprising young fella did. That takes the idea to a new level.

Update 2010-06-18: There's a new, officially licensed product on the market. The "Wireless Ultra Sensor Bar" features according to Destructoid a "larger size of the sensor bar allows for better communication with multiple people and at greater distances too". Obviously feedback has gotten back to Nintendo that some of us don't game in a small box with a 15" monitor. :)