Get rid of Kindle Paperwhite's backlight

[DuckieTigger]

It is all really interesting and all, with all the weird stuff of forward / backward / sideways / insideout voltage of LEDs. It has run its course. As far as the Paperwhite is concerned, setting the device to 0 is good enough. The LEDs do not emit any light and that is a desired thing when this thread is about turning the light OFF. At 0 it is off. End of story.

Stay tuned for a new (different) method to turn the light off. Give me some time to touch that up on my stupid phone.

[knc1]

[DuckieTigger]

Credit to Alan (aka alansplace) for making me look into this on an unrelated topic. Thank you, you made me hardware-hack my PW today.

Do not worry, all that is needed is a small magnet and any way to strap it to the PW so that it can be easily removed / reattached. That is it on hardware needed.

Now how to turn the light OFF? Follow these 2 steps:

1) disable screensaver in search bar by entering and hitting return after this:

~ds

2) attach your magnet so PW would normally go to sleep with wake / sleep function

Ta Da, the light is off.

Few things you need to know:

- you can't enter screensaver sleep mode by closing the cover or pushing the button shortly - nothing will happen other than the light turns off when using cover (that is where the magnet above comes in)

- you can still put PW to sleep, but you must remove the magnet, push power button for few seconds (about 4 maybe) to enter white screen sleep mode. Again, light must be turned on, or PW won't enter white screen sleep mode

- the screensaver will not come on after 10 minutes (thought I mention that as ~ds disables that)

- the light can be turned on and off by simply removing / attaching magnet

- to return normal operation a restart is necessary (menu->settings, then menu->restart) - screensaver is back , attaching the magnet sleeps device again

- last not least: does not require Jailbreak or USB Network
Happy Hacking



p.s.: Thank you Amazon for this undocumented feature.

Update: See post #80 or directly this post for a nice guide on what magnet to use and where to put it. That post is for waking / sleeping with a cover. So you need to adjust accordingly to make it work for turning the light off. See picture #5 there for placement.

[geekmaster]

Originally Posted by ProDigit

Forward voltage is different from backward voltage.
There are diodes that have a backward voltage of 97V as well.
I'm not saying that these are the leds installed in the kindle, all I'm saying is that the backward voltage with 'device -1' is not more than a few milli-volts, and would not harm the leds, neither would reversing polarity of full battery voltages cause any damage to the leds.
More than likely battery voltage is around 3.8V; but some e-devices have 2 batteries in series having 7.4V.

You are overstating the obvious, and you are paraphrasing things you quoted.

Also, considering that the brightness is an 8-bit unsigned value, your -1 value would be treated as 255, which is maximum brightness, and certainly not darker than "no light" as you seem to be expecting from how I (and others) have interpreted your posts.

Where did you get that 97V reverse breakdown voltage? There are diodes that have a much higher limit than that arbitrary value.

And yeah, dead horse... 0 is fully off. 255 is fully on. Anything in between is in between. And anything else is just silly...

[knc1]

Originally Posted by DuckieTigger

Credit to Alan (aka alansplace) for making me look into this on an unrelated topic. Thank you, you made me hardware-hack my PW today.

Do not worry, all that is needed is a small magnet and any way to strap it to the PW so that it can be easily removed / reattached.

https://www.mobileread.com/forums/sho...1&postcount=25

[alansplace]

Originally Posted by DuckieTigger

Credit to Alan (aka alansplace) for making me look into this on an unrelated topic. Thank you, you made me hardware-hack my PW today.

Do not worry, all that is needed is a small magnet and any way to strap it to the PW so that it can be easily removed / reattached. That is it on hardware needed.

Now how to turn the light OFF? Follow these 2 steps:

1) disable screensaver in search bar by entering and hitting return after this:

~ds

2) attach your magnet so PW would normally go to sleep with wake / sleep function

Ta Da, the light is off.

Few things you need to know:

- you can't enter screensaver sleep mode by closing the cover or pushing the button shortly - nothing will happen other than the light turns off when using cover (that is where the magnet above comes in)

- you can still put PW to sleep, but you must remove the magnet, push power button for few seconds (about 4 maybe) to enter white screen sleep mode. Again, light must be turned on, or PW won't enter white screen sleep mode

- the screensaver will not come on after 10 minutes (thought I mention that as ~ds disables that)

- the light can be turned on and off by simply removing / attaching magnet

- to return normal operation a restart is necessary (menu->settings, then menu->restart) - screensaver is back , attaching the magnet sleeps device again

- last not least: does not require Jailbreak or USB Network
Happy Hacking



p.s.: Thank you Amazon for this undocumented feature.

How about those of us who don't have a case with a magnet? I do have screensaver disabled and do not have a magnet I'm aware of (case has an elastic to keep it closed). How big a magnet and where does it go if you 'strap it'?

[knc1]

Originally Posted by alansplace

How about those of us who don't have a case with a magnet? I do have screensaver disabled and do not have a magnet I'm aware of (case has an elastic to keep it closed). How big a magnet and where does it go if you 'strap it'?

Look one post above your own.
OR: https://www.mobileread.com/forums/sho...1&postcount=25

Above post now fixed to include a "where to put it" picture. (geesh)

[alansplace]

Originally Posted by knc1

Look one post above your own.
OR: https://www.mobileread.com/forums/sho...1&postcount=25

Above post now fixed to include a "where to put it" picture. (geesh)

Duh!

'Bring this assembly (open side towards Kpw) within 1/4 inch of the Kpw', where exactly (bottom edge, top edge middle of screen....etc.)?

[knc1]

Originally Posted by alansplace

Duh!

'Bring this assembly (open side towards Kpw) within 1/4 inch of the Kpw', where exactly (bottom edge, top edge middle of screen....etc.)?

picture #5

[twobob]

Originally Posted by alansplace

Duh!

'Bring this assembly (open side towards Kpw) within 1/4 inch of the Kpw', where exactly (bottom edge, top edge middle of screen....etc.)?

*Looks at picture*

About an inch right of where it says KINDLE???

You looking at some other picture?

[alansplace]

Originally Posted by knc1

picture #5

Yikes, didn't see that one before! Did you just add it? Ok, now I get it and I also just discovered that my cover has a built-in magnet!!

Thanks!

[DuckieTigger]

Originally Posted by alansplace

Yikes, didn't see that one before! Did you just add it? Ok, now I get it and I also just discovered that my cover has a built-in magnet!!

Thanks!

That built in magnet is great for when you have the screensaver enabled to put your PW to sleep. If you have screensaver disabled, however, it still turns the light off, but the cover has the bad habit of covering the screen as well.

Sounds like that you have an aftermarket cover that has rubber straps around the corners? That would be a perfect place to slide the magnet under. Maybe taped to a little piece of black cardboard big enough to cover up the black part with "kindle" on it. This way you simply slide that in under the bottom left and right rubber straps, align it with the corners, and the light goes off. If you are crafty enough you might not even notice that there is an object out of place.

And Alan, thank you for the Karma. Have some back in return, as you made me dig into this and discover it in the first place.

[alansplace]

Originally Posted by DuckieTigger

That built in magnet is great for when you have the screensaver enabled to put your PW to sleep. If you have screensaver disabled, however, it still turns the light off, but the cover has the bad habit of covering the screen as well.

Sounds like that you have an aftermarket cover that has rubber straps around the corners? That would be a perfect place to slide the magnet under. Maybe taped to a little piece of black cardboard big enough to cover up the black part with "kindle" on it. This way you simply slide that in under the bottom left and right rubber straps, align it with the corners, and the light goes off. If you are crafty enough you might not even notice that there is an object out of place.

And Alan, thank you for the Karma. Have some back in return, as you made me dig into this and discover it in the first place.

Nope, I don't much like that design. Here's mine ($12.99 and free shipping):

And it has a handy spot at the lower right corner to put the magnet anyway (and it'll be hidden).

Well you did a mighty fine job of research!

[knc1]

Originally Posted by alansplace

Nope, I don't much like that design. Here's mine ($12.99 and free shipping):
Attachment 98996
And it has a handy spot at the lower right corner to put the magnet anyway (and it'll be hidden).

Well you did a mighty fine job of research!

Does that also work as a "dock" to hold the USB-to-Audio hardware?

[alansplace]

Originally Posted by knc1

Does that also work as a "dock" to hold the USB-to-Audio hardware?

First off I have no idea as to an answer to your question. Secondly I'm unaware of the hardware you are talking about.