Post by: liquid-core on December 04, 2006, 05:44:00 PM
I am currenly working on building a wireless sensor bar that reads the dimensions of the TV (thx for the idea grim
). The questions I have are pretty simple:1) Will IR LED with the following specs work:
Infrared LEDS
3mm
T1
Peak Wavelength: 980nm
1.5VDC
2) AA batteries give off around 1.5V when new. Would these be suitable to power the above LEDs or should I look into stronger/ more powerful batteries? I know that the LEDs run off of 1.5V, but the batteries do wear down, once they get to the estimate 1.35V I will run into problems correct?
Heres a description of what I'm building:
My sensory "boxes" will be L-shaped. On the long end of the "L" the battery will be held. Along the shorter side the IR LEDs will be located as well as the resistors and switch (just a nice little slider switch). The encasement will be constructed of plexiglass (the front piece will be tinted) and then covered with a thin layer of metal (I figured that it will add a nice industrial look to it and make it all pretty) excluding the front piece. I think I will also add a blue LED that will light up the exposed pieces of plexiglass (don't think it will cause problems) for a nice Wii like touch and so I know when the devices are on or off.
I will also test if the LEDs should be horizontal to the top of the TV or if them being vertical will make a difference.
LETS HEAR YOUR IDEAS!
O'Malley
Post by: yaazz on December 04, 2006, 06:01:00 PM
Post by: liquid-core on December 04, 2006, 06:13:00 PM
O'Malley
Post by: SR388 on December 04, 2006, 06:30:00 PM
not really wireless, but it will work better than stock
I may may a wirless version with a switch and rechargable batteries sometime later
Post by: Y26tav on December 04, 2006, 06:54:00 PM
Post by: liquid-core on December 04, 2006, 06:55:00 PM
O'Malley
Post by: SR388 on December 04, 2006, 07:09:00 PM
It would be easier, but I don't like batteries
Post by: liquid-core on December 04, 2006, 07:36:00 PM
Just my .02 cents.
O'Malley
Post by: SR388 on December 04, 2006, 07:48:00 PM
but once again, you have to look at the pros and cons:
bat idea:looks clean - have to replace batteries and deal with voltage drops
Transformer Idea: doesn't need an off switch or replacement batteries - has to have very small wires coming out the back to the transformer
Post by: liquid-core on December 04, 2006, 07:54:00 PM
I think once I get mine done and tested (if it works well) then I will write up a tut on how to make my version.
O'Malley
Post by: SR388 on December 04, 2006, 09:15:00 PM
Post by: grim_d on December 05, 2006, 05:09:00 AM
QUOTE(liquid-core @ Dec 5 2006, 12:51 AM) 
(thx for the idea grim
). me?
Post by: omegajedi on December 05, 2006, 06:27:00 AM
photoshoped image of what it might look like
Post by: liquid-core on December 05, 2006, 07:30:00 AM
QUOTE(grim_d @ Dec 5 2006, 04:16 AM)
me?
I thought it was you...
O'Malley
Post by: grim_d on December 05, 2006, 07:46:00 AM
QUOTE(liquid-core @ Dec 5 2006, 02:37 PM)
I thought it was you...
O'Malley
i have no idea, memory like a fish
cool discussion anyways, keep it coming
Post by: SR388 on December 05, 2006, 12:16:00 PM
or larrimus
Post by: twistedsymphony on December 05, 2006, 01:46:00 PM
QUOTE(twistedsymphony @ Dec 1 2006, 08:40 AM)
Post by: SR388 on December 05, 2006, 05:54:00 PM
Post by: SR388 on December 05, 2006, 09:44:00 PM
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
Post by: twistedsymphony on December 06, 2006, 06:09:00 AM
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.
Post by: SR388 on December 06, 2006, 11:43:00 AM
Post by: mrRobinson on December 06, 2006, 01:31:00 PM
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.
Post by: liquid-core on December 06, 2006, 08:51:00 PM
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
Post by: twistedsymphony on December 07, 2006, 02:09:00 PM
heck might as well built it to run on a bunch of D-Cells... then you wont have to replace those things for years
Post by: liquid-core on December 07, 2006, 03:54:00 PM
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
Post by: Y26tav on December 07, 2006, 06:28:00 PM
Post by: SR388 on December 07, 2006, 06:57:00 PM
otherwirse the cursor will go nuts
Post by: drhouse on December 07, 2006, 06:59:00 PM
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.