BTW I would like to try RGB LED backlighting to enhance the colour gamut of an LCD, apparently (as in I am guessing) this is how the high end monitors do it.

You are the first to disagree with me and claim actual experience. In the past it’s always been a “well, I read it on the net somewhere” or “so and so told me” kind of thing.

So now I think I am going to have to build something to test this now. Like maybe take a microcontroller and program it to PWM a LED at different duty cycles, and then build a constant current driver and adjust it to match the brightness and then measure the current and compare to the PWM duty cycle.

If I really wanted to get fancy, I could make the microcontroller control both the PWM and the constant current source and be able to switch which goes to which LED and change which LED was being adjusted. The microcontroller could be programmed to do a sort of double blind test that way because I wouldn’t know which LED was constant current and which LED was PWMed when I was matching the brightness. So many projects to do, so little time. :)

Unfortunately I can locate none at the moment. My main reason for believing such is my own experience when I replicated a test with a 10 segment LED bar graph, with the segments driven in 10% duty increments, and to my eye the gradations were closer to logarithmic (I had printouts of a linear and logarithmic scale, both in 10 gradations to match to). The phenomenon may be due to some other factor but I have seen it in practice.

A photograph of the experiment showed a linear scale, but this was not as it appears to the eye, probably due to some process in the eye or the brain in processing the image.

Do you have any references to these studies? I’ve had this debate with people before and nobody has ever been able to come up with any. I personally think it is a myth.

I have designed several multiplexed LED displays, and my own personal experience is that it is reasonabley close to linear. I’ve pushed it as far as a 10:1 multiplexing and in that case I did have to run 10 times the current to get the same brightness.

this is the site for the netbsd-hpcmips distribution (what runs on the mobilepro). huge list of supported devices and to what extent they are supported. of course, some of these devices are rather obscure, and you’d have to do some googling to get the finer points, but a good starting point at least.

What I’m looking for is something to become my alarm clock (streaming MP3 through wireless) and my small portable to keep near my bedside when I have an idea in the middle of the night. Currently I have a Toshiba E740 and it’s really starting to annoy me as every time I set it down it hard-resets and loses all my data that I don’t save to my CF Card.

Thanks for any help.