Thread: Details on Sensor Bar LED configuration

Hi there,

I'm making a currently setting up my Wii with a projector. I'll be putting the Wii next to the projector (which is mounted to the ceiling) and therefore will make my own sensor bar to put under the screen.

Making the sensor bar is the easy bit. What I'm wondering is: is there an optimal distance of the IR LEDs? I'm pretty sure Nintendo simply chose a distance which matches most TV sets. So, for a 200cm image diagonal, I'd probably chose a larger distance--or is this BS?

Does anyone know any details about the triangulation algorithm used? Or can give me advice on what distance to chose?



Edited 1 time(s). Last edit at 02/18/2011 10:23AM by brownieman.

All I know is the closer the LEDs are to each other, the closer you have to be to the screen. Sensor. You know what i mean.



Edited 1 time(s). Last edit at 02/18/2011 11:15AM by bg4545.

Why not just use the original bar powered by something other than the wii?

Good point; however, I've given it a try and the LEDs are simply too close together.
With my projector, I have an image width of a bit more than 150cm. My IR sources (for figuring out the distance, I used candles) are about 52cm apart to give the right response--if I use the original bar, I basically have to point right at the IR sources.

I'm pretty sure the Wii-Remote simply uses the two IR sources to figure out the bottom line (or top line) of the screen and assumes the LEDs are placed at about a half distance of the total screen width, centered around the middle.

It uses them for Z-distance as well, have you played pool in Wii Play?

Hi tueidj,

thanks for that input. I don't have Wii Play, so I haven't tried this. This is a good point, though: If my assumptions are correct, gauging the z-distance would scale linearly with the LED distance, meaning I'd have to move the whole thing more than twice as far in z-direction, which would be a bugger.
Are there any other games that use z-distance information?

this is an impossible question to answer. you really need to factor in the distance between the LED and the wiimote.


i have a 32" TV and the stock wii sensor bar. it works good for playing 10ft from the TV. but playing 20ft from the TVis impossible. the wiimote cannot track correctly and the pointer constantly disappears. i got an adjustable sensor bar that moves the LEDs from the stock width to 6 inches wider. now my wiimotes work fine 20ft away from the TV.

the TV is the same size, but the distance between the LEDs is different. without factoring in the distance you will be playing from the LED source, you cant generate a ratio from this.



Edited 1 time(s). Last edit at 02/23/2011 05:45AM by giantpune.

Quote
giantpune
this is an impossible question to answer. you really need to factor in the distance between the LED and the wiimote.


i have a 32" TV and the stock wii sensor bar. it works good for playing 10ft from the TV. but playing 20ft from the TVis impossible. the wiimote cannot track correctly and the pointer constantly disappears. i got an adjustable sensor bar that moves the LEDs from the stock width to 6 inches wider. now my wiimotes work fine 20ft away from the TV.

the TV is the same size, but the distance between the LEDs is different. without factoring in the distance you will be playing from the LED source, you cant generate a ratio from this.

Which has nothing to do with the distance between the LEDs, and all with the brightness. I think the default sensor bar contains 2 leds per side. If you boost that to 4 LEDs you get a much better distance.

No, it is in fact to do with their positions - the further away you are the closer the points of light appear to be to the wiimote sensor until eventually they merge into one. It has to be able to find at least two distinct points of light.

I've never seen the dots in the test screen (somewhere in the Wii settings) merge into a single one, but if I move the Wiimote to far from my TV they start to jitter on/off. I guess it also has to do with the amount of background light (lots of windows in my room) And I had this light standing next to my TV, which the Wiimote sometimes saw as 3th spot and got confused.

if your planning on making a custom sensor bar, why not make 2 seperate 'eyes' rather than a bar. this way you could experiment with distance between them

Btw, seeing this is for a projector, I came across this project the other day: [spritesmods.com]
Seems to make much more sense with a projector :-)