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-   -   IR Port used as a thermometer? (https://talk.maemo.org/showthread.php?t=61327)

TiagoTiago 2010-08-31 02:41

Re: IR Port used as a thermometer?
 
I don't think the frequency of the IR led is the same infrared frequency used in heat seeing cameras, wouldn't work even if it was a transceiver.

Btw, can you control the patterns of flashing for the proximity sensor? And can it both flash and read flashes fast enough for irDA use? What's is the range?

shadowjk 2010-08-31 20:25

Re: IR Port used as a thermometer?
 
My guess is that the proximity sensor internally modulates its signal and looks for that in the return so it doesn't mistake the light bulb in your room for a return signal, etc..

Maybe two N900 face to face at exact right angle and distance could communicate with eachother over proximity sensor... but wlan and bluetooth would be easier for sure.

TiagoTiago 2010-08-31 20:41

Re: IR Port used as a thermometer?
 
if it does work, perhaps it could be used to record IR signals from IR remotes not in the database, and would probably be usefull for exchanging data in situations where WIFI and bluetooth radiation is not allowed like in an airplane, and if it's possible to make it compatible with irDA, it would also be usefull for using with older/cheaper devices that don't got bluetooth much less WIFI

ctbeiser 2010-08-31 20:48

Re: IR Port used as a thermometer?
 
Quote:

Originally Posted by TiagoTiago (Post 803573)
if it does work, perhaps it could be used to record IR signals from IR remotes not in the database, and would probably be usefull for exchanging data in situations where WIFI and bluetooth radiation is not allowed like in an airplane, and if it's possible to make it compatible with irDA, it would also be usefull for using with older/cheaper devices that don't got bluetooth much less WIFI

I don't think it's possible to get it to do IrDA, and even if it were, I'm pretty sure that there are bigger and better things to develop. If someone wants to do it, all the power to them, but IrDA strikes me as something that doesn't really matter, even if it could work.

cashclientel 2010-08-31 21:10

Re: IR Port used as a thermometer?
 
Quote:

Originally Posted by TiagoTiago (Post 802844)
I don't think the frequency of the IR led is the same infrared frequency used in heat seeing cameras

it is, infrared=infrared. heat seekers are in the same frequency.

whether or not the N900 can recieve data seems to be unknown - i'm yet to see anyone with knowledge make a case either way. personally i think it can but there is no driver for it.

if the N900 ir sensor can detect ir iinput it can not be used to measure heat like an ir themometer - thats a different kind of sensor. theory is good though.

TiagoTiago 2010-08-31 21:22

Re: IR Port used as a thermometer?
 
I don't think that is accurate, there are a whole lot of frequencies that are bellow red, just like there are pretty much about as infinite many above violet; X-rays aren't the same thing as what comes out of those UV lamps that charge glow in the dark material and light up fluorescent ink, you know?


I'm pretty sure the frequencies emitted by warm bodies (at least those not too close to being incandescent in visible light) , are not the same frequencies as IR LEDs emit, though things like open flames and the Sun usually emit on both ranges, among others.

TiagoTiago 2010-08-31 21:37

Re: IR Port used as a thermometer?
 
please read this; https://secure.wikimedia.org/wikipedia/en/wiki/Infrared

and then come back

cashclientel 2010-08-31 22:59

Re: IR Port used as a thermometer?
 
Quote:

Originally Posted by TiagoTiago (Post 803612)
X-rays aren't the same thing as what comes out of those UV lamps that charge glow in the dark material and light up fluorescent ink, you know?

yes.

Quote:

Originally Posted by TiagoTiago (Post 803612)
I'm pretty sure the frequencies emitted by warm bodies (at least those not too close to being incandescent in visible light) , are not the same frequencies as IR LEDs emit, though things like open flames and the Sun usually emit on both ranges, among others.

Completely correct.

it needs to be a differend kind of sensor - very focused and especially sensetive in a specific range. the N900 hardware is designed for the opposite of this.

I've thought about it and whether or not the hardware could detect the range for this application we'll never know; so little point debating it. likely there is some kind of filter in there or else the software does something but god knows. that fact is semantics anyway for my previous reason of accuracy.

tzsm98 2010-08-31 23:19

Re: IR Port used as a thermometer?
 
I want to thank everyone who has contributed to this thread. I now fully understand that this is not going to happen on the N900 for:
  • Hardware lacking reasons
  • Driver lacking reasons
depending upon who you ask. Either one is a show stopper. Maybe on a future product.

gerdich 2010-09-01 10:09

Re: IR Port used as a thermometer?
 
The hardware is not lacking.

But is isn't the proximity sensor but the ambient light sensor.

It is specialized on natural light AND infrared light.
There is an algorithm that mixes all different sorts of light and outputs only two key values.

If we can access to this algorithm, we can extract infrared values in a broad spectrum.

But no suitable driver exists.

(In fact we have to do the inverse calculation of the custom use. The sensor has two photodiodes. The second one is only about infrared to calculate the effect of infrared light on the first sensor to eliminate infrared influence on the value of the first. The custom goal is to have only the value of visible light.

We have to do the inverse: We calculate only the value of infrared light and eliminate the influence of visible light.)


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