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Comment by narwally | Hacker News Reader

When my sister lost the "sensor bar" on her Wii I showed her how to use a pair of candles to replace it. The sensor bar is just a a set of IR lights that the camera on the wii-mote detects.

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Yeah it's funny that it is called a sensor bar when it has no sensors.

For my undergrad, we had a cross-major project to build a robot that shot pingpong balls at various targets that were tagged with IR lights. We used 2 wiimotes to calculate the 3D space.

Valve lighthouse "trackers" work in a similar, albeit slightly more complicated, way.

Yes! I am now imagining a vive tracker built out of two candles spinning at 300hz

What could go wrong!?

Yeah I did that one time as well! I had forgotten the sensor bar at someone's place after taking the Wii there.. had it back and home and remembered it's just IR LEDs or whatever, figured two candles should emit the ~same light and, lo and behold, worked quite well! IIRC it was a bit jittery due to the candle flames wavering about, but hey, better than nothing :)

I'd imagine a pair of candles would cause the cursor to jump around a lot because of the flickering - how did you solve that problem?

With a clean, dry wick it's pretty easy to get a very still flame for a long, long period of time. Though if you have a fan or something blowing, you're out of luck.

I imagine a vigorous game of Wii Tennis will cause those candles to flicker.

And will provide a convenient excuse why I was unable to return that serve.

Unfortunately your excuse is no good, because Tennis does not use the Sensor Bar.

Well then that's my excuse! I thought it did, so I was making sure to point the controller in the proper direction, while my opponent was cheating and flicking it any which way.

Look, it wasn't my fault, ok?

Use a candleholder that includes a glass sheath. The solution has been known for a long, long time, because a major cause of flickering unprotected candles -- or even extinguishing them -- is that you walk around while holding them.

Miniature lightbulbs works to the same effect. Anything that emit near IR works.

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