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[SR388]

i think it was twisted that came up with the idea
or larrimus

[twistedsymphony]

QUOTE(twistedsymphony @ Dec 1 2006, 08:40 AM)

that was MY idea you Insensitive Clod!  

http://forums.xbox-s...&...t&p=3774280

[SR388]

now that that is all cleared up....lol

[SR388]

I just remembered something rather important

wii need to put the IR emitters either at the very top corners of the tv (maybe even on the very top at each corner)
or at the very bottom corners of the tv

[twistedsymphony]

That's right. you need to make sure you have 2 discrete IR sources, imagine a cluster of LEDS and squint your eyes and it becomes a sort of ball of light, the Sensor bar has two of these and it uses these as a point of reference to determine where the remote is positioned in relation to the TV.

I'm fairly certain it's designed to have these balls of light either above or below the display NOT near the center.

Biangulation only works if the points of reference rest along a known edge. Chances are when you calibrate the controller it determines whether you've placed the sensor bar on the top or bottom of the display.

If you're not placing them along a known edge then you'd need to calculate it using Triangulation.

The controller is built around the assumption that the known edge would be either the top or bottom  and it's build for Biangulation not Triangulation.

So any home built sensors would have to have 2 IR sources and they would have to reside either along the bottom edge or the top edge of the display.

This is just my theory anyway.

I did a project in college where I developed a system for calculating the position of something using 2 sensors and biangulation. If people are interested I can see if I can dig up my calculations and diagrams for how it works and the equations involved.

[SR388]

Correct, as the Wii will only look for a tv abox or below the bar, not both

[mrRobinson]

QUOTE(twistedsymphony @ Dec 6 2006, 08:16 AM)

Chances are when you calibrate the controller it determines whether you've placed the sensor bar on the top or bottom of the display.

Your 100% right except it isn't as smart as you think.  You actually tell it if your sensor bar is located below  your tv or above your tv (it does no determination on its own).  then the calibration is just sensitivity and you adjust until you only see two dots on your screen.  Setting sensitivity too high and you'll see 3 or more dots which make little finger pointer hopped up on crack.

[liquid-core]

QUOTE(drhouse @ Dec 6 2006, 12:42 PM)

LEDs are low-current devices and not all of them need 5V. This one from RadioShack operates at 1.2V and 29mA. You can run it off 1.5V but you'd need a 50-ohm resistor in series to limit the current to 30mA.

So you can power it with one AA or AAA battery. Don't use 9V batteries (even if you divide the voltage down) because of their low capacity. For Energizer alkaline batteries, the 9V has 625mAh while the AA has 2850mAh. Do the math and that battery can last (theoretically) 95 hours.

Why are you guys making a new sensor system? Is it supposed to out-perform Nintendo's sensor bar?

Correct. It is supposed to be more accurate and thats about it. Its just for fun for me.

O'Malley

[twistedsymphony]

If you build a circuit to pulse the LED at a high speed you can easily extend the battery life by large multiples...

heck might as well built it to run on a bunch of D-Cells... then you wont have to replace those things for years  

[liquid-core]

Sounds like a plan to me. Any suggestions on how to build a circuit that makes the light pulse? I'm interested in learning about these kind of things.

O'Malley

[Y26tav]

Can the wii mote only sense two points? or could you put two on top and two on bottom to increase preformance even more? or to go all the way outline your tv with Ir leds and tap the 12v tv power so they are always on and no need to have batterys.... that would kinda kill the whole portable thing, But i have a small tv that is mighty carry-able.

[SR388]

yep, only 2 points

otherwirse the cursor will go nuts

[drhouse]

QUOTE(twistedsymphony @ Dec 7 2006, 04:16 PM)

If you build a circuit to pulse the LED at a high speed you can easily extend the battery life by large multiples...

heck might as well built it to run on a bunch of D-Cells... then you wont have to replace those things for years  

I took your idea and drew up a little 555-timer circuit that would pulse the LED.

Imageshack link.

I decided to go with 100KHz because they have a graph on the datasheet and that's the highest frequency there  (that's not to say the 555 chip can only go up to 100KHz on astable mode .. I'm not sure what the upper limit is).

I followed the basic circuit diagram in the datasheet and improvised the LED part. The 555 chip will put out positive voltage pulses at 100KHz. In the math, it works out that the LED will be on for about 8 microseconds and off for 2 microseconds.

During a high pulse, the base of the transistor has a current through it so the transistor goes on (connection between collector and emitter). That grounds the anode of the LED and a current flows, turning the LED on.

During a low pulse the base has no current so the transistor is off (no connection between collector and emitter). That causes an open circuit for the LED so no current flows.

The 100K resistor is in series with the base to limit the current since very little is needed).



I just drew this up quickly so there's plenty of room for optimization. I don't feel like doing the math, but it may work out that this circuit will use more battery power than just an LED and a resistor (but I don't think so since 555's draw very little current).


**Oh, I just realized I forgot to add a switch. It goes right after that capacitor, in series with the 6-Volt line.