I've searched for an answer on this and the closest I can find is this discussion on the proximity sensor's delays: http://talk.maemo.org/showthread.php?t=67026

This is not what I'm looking for.

When I use my N900 indoors, the proximity sensor works fine.
However, if I use it outdoors in the daytime, when I take it away from my face to look at it to hang up, see if I have a signal, or even answer after pulling it out of my pocket, the display will either flash on then blank again, or simply won't come back from being blanked at all.
My only option for using the phone at this point is to open the keyboard (I have rotation enabled) as that overrides the sensor. Kind of awkward when trying to get on a train carrying a computer.

I tested the sensor (with proximityd) and found that in a dark room, it detects my thumb from about 20mm away... double the distance that I read it is supposed to sense.

Note that I live in South Florida... likely a tad brighter sun than many here are getting this time of year. I know the sensor is an IR emitter/detector pair, but that nuclear furnace puts out a tremendous amount of IR down here.

Hence my question: Does anyone know of a way to adjust the sensitivity of the proximity sensor?
I'd like to dial it back by about 70%.

May be the proximityd is exactly the cause of the issues you've to deal with? Have you tried to remove it and test the response again?

In addition, are you sure the problem isn't caused by the refraction of the sreen protector under strong daylight? Have you tried punching a hole in where the screen protector is blocking the sensor?

P.S. Don't worry about the radioactive cloud from Japan. I read from local news that it'd take 6 days to reach where you leave, you still have plenty time to evacuate.

I installed proximityd just this evening as a dependency of shortcutd, and decided to test the sensor since this has been annoying be since the first time I answered the phone in the sun.

I'm not using a screen protector.

Edit: Clarification: I decided to test it after doing searches and finding it should activate at about 10mm.

I know many are insisting that shortcutd should not cause any stability issues, and I'm sure it's stable enough for day-to-day use. However, it's no harm to test, is it?

You'd also like to see if you've installed advance-power-* anyway.

What I'm saying is the problems preceded the installation of proximityd... this has been annoying me for some time - I only just installed it, so it can't possibly be the cause (unless it has some sort of temporal overload capability that allows it to influence the past ).

As to Advanced Power (and AP Monitor), yes... I have those installed. Do those, somehow affect the sensor sensitivity?
I installed them so I could get more details about the battery capacity. (I'm still trying to get all the functionality I have with my highly tweaked N800)

Edit: To be clear - proximityd was installed late enough in the day that I haven't had the problem since it was installed (the Sun down too far).

It's no harm in testing..

True, but I don't see the connection.
As far as I can tell, AP has no more to do with the proximity sensor than Catorize (also installed).
In fact, I'd expect the Enhanced Kernel to have more influence over it.

I'll have to wait 'til I'm in the Sun again to test.

Good Luck

Nope... I uninstalled both AP and AP Monitor, rebooted to make sure no remnant existed... made a phone call in the setting sun and could not get the screen back without sliding the keyboard open.

Indoors it's working fine.

The sensor is just too darned sensitive to ambient IR.

Would they really make something like this with no way to adjust it?