Hi everybody,
I was thinking of getting trackir for about a year now and am still not sure whether I will or not. My main concern is the Infrared radiation emitted by the device.. to be honest I am not really sure about the whole thing and am not really a science person, but 1 thing I do know is that radiation is bad and a lot of it is very bad...
So if anybody has any useful input or hopefully can explain how trackIR works - what is being emitted out of what and the consequences, that would be quite helpful..
Thanks!
Infrared radiation
Re: Infrared radiation
I doubt trackIR can output as much infrared light as the sun does at sea level, but since I don't have the specification on how much it outputs i can't say for sure. But some have reported that TrackIR is useless in open daylight, I haven't had that problem myself, proving that the suns IR is stronger than TrackIR.
although Infrared radiation can harm the eyes, this is mostly true in industrial environment, but at that kinda level all the color spectrum ranges are dangerous.
although Infrared radiation can harm the eyes, this is mostly true in industrial environment, but at that kinda level all the color spectrum ranges are dangerous.
Re: Infrared radiation
The TrackIR/SmartNAV operates by tracking reflected or emitted IR light that is imaged by a CMOS sensor. The sensor and emitters are tuned to 880nm, slightly above the visible spectrum, you can see them emit a slight glow when the room lights are off, and this is the very upper end of the red spectrum. The sensor and IR LEDs are covered by a very special plastic that we custom designed with Bayer to block all light below 820nm, it passes all light above this point, it is called a band pass filter.
The LEDs emit at 880nm and are standard off the shelf IR LEDs; we run them all the time when the unit is turned on. There are 4 of them and they each have a total radiant output of about 23mw/sr, which is 23miliwats per ster radian. Total output power is NOT 4 X 23 mw/sr as the LEDS do not overlap exactly; they create a coverage pattern with slight overlap at the edges. Also, the LEDs to not emit a uniform brightness, they have an angle to half intensity, so the center of the overlapping LEDs is the SAME brightness as the center of each LEDs output, hope that makes sense.
Your eyes ARE sensitive to IR light, you can't see it, but your eyes will register the "power" of the light, your pupils will shrink down as if you were looking at light in the visible spectrum. Remember, we are just slightly above red in the visible spectrum. You won't feel your pupils getting smaller when our device turns on because we are a relatively low level of light for an average room condition. If you turn out all the lights in the room, put the unit about 1 foot away from your face and watch your eyes in a mirror, you will see your pupils contract, they are "seeing" the IR light.
As for the amount of power the LEDs output, it is many of times lower than simply going outside, not to mention on a bright sunny day. As I had seen posted before, we are a small fraction of the IR output from a normal incandescent light bulb. ANSI references spec ANSI Z 136.1 - 2000 for laser power emission, but we are not a laser, so in the back of the spec they reference ANSI/IESNA RP-27.1-96, which is the spec for lamp output, basically what we are and what ANSI says to use. Maximum exposure for our wavelength range, which is from 700nm to 1100nm is 10mw/cm2. To convert our power output, which is about 30mw/sr, we apply sr x 1cm2/distance2. Typical user distance is 18" or about 45cm (on the conservative side, most users are further away), so 30mw/2025 = .015mw/cm2. Needless to say, we are on the safe side!
If you have any further questions or concerns please let us know.
The LEDs emit at 880nm and are standard off the shelf IR LEDs; we run them all the time when the unit is turned on. There are 4 of them and they each have a total radiant output of about 23mw/sr, which is 23miliwats per ster radian. Total output power is NOT 4 X 23 mw/sr as the LEDS do not overlap exactly; they create a coverage pattern with slight overlap at the edges. Also, the LEDs to not emit a uniform brightness, they have an angle to half intensity, so the center of the overlapping LEDs is the SAME brightness as the center of each LEDs output, hope that makes sense.
Your eyes ARE sensitive to IR light, you can't see it, but your eyes will register the "power" of the light, your pupils will shrink down as if you were looking at light in the visible spectrum. Remember, we are just slightly above red in the visible spectrum. You won't feel your pupils getting smaller when our device turns on because we are a relatively low level of light for an average room condition. If you turn out all the lights in the room, put the unit about 1 foot away from your face and watch your eyes in a mirror, you will see your pupils contract, they are "seeing" the IR light.
As for the amount of power the LEDs output, it is many of times lower than simply going outside, not to mention on a bright sunny day. As I had seen posted before, we are a small fraction of the IR output from a normal incandescent light bulb. ANSI references spec ANSI Z 136.1 - 2000 for laser power emission, but we are not a laser, so in the back of the spec they reference ANSI/IESNA RP-27.1-96, which is the spec for lamp output, basically what we are and what ANSI says to use. Maximum exposure for our wavelength range, which is from 700nm to 1100nm is 10mw/cm2. To convert our power output, which is about 30mw/sr, we apply sr x 1cm2/distance2. Typical user distance is 18" or about 45cm (on the conservative side, most users are further away), so 30mw/2025 = .015mw/cm2. Needless to say, we are on the safe side!
If you have any further questions or concerns please let us know.