Is this a crazy idea or not?

[knc1]

Originally Posted by knc1

As long as the run time is only 2/11 of the 60 second interval, it will only add up to 2 hours of run time in the 11 hours elapsed.

For an example - look up the Kindle Clock - which updates the screen once a minute.

[Cinisajoy]

Originally Posted by knc1

For an example - look up the Kindle Clock - which updates the screen once a minute.

Thanks for the explanation.

[xorlof]

Originally Posted by Cinisajoy

Your best bet would be to set up a kindle and check your battery time.
1. No matter the router, you will have to have the wifi on.
Do you have a test kindle to see if your program will work?

Right, I will need Wifi on all the time. And yep, I have a Kindle Touch (same model as I'm proposing using).

Originally Posted by knc1

I do not mean idle, I do mean asleep for the other 9 hours.

Keep in mind, the Kindles have a meta-stable display - -
they do not have to be running for the display to continue showing what was last written to it.

That might be the point you overlooked when you thought the device was running while displaying a book page.
"meta-stable" == does not require refresh

Oh, so this definitely is new information to me! I understand that the display doesn't take any electricity except when changing its image, but I didn't understand that the device is completely asleep between changing book pages. I thought it was idling and only went to sleep when the screen saver kicked in. (Assume an unmodified Kindle here). If that's the case, how does the touchscreen and home button work when reading, but don't after the screen saver comes on. If they use the same power and there isn't a sleep mode where things are more powered down, it seems like you'd want to be able to use the touchscreen or home button to wake up the device. Is that just a UI decision Amazon decided to make?

Secondly, when is it not asleep then? I haven't jailbroken my kindle, but I assumed I could SSH into anytime after I "turned it on" but before the screen saver kicked in (even with a book image on display). If sleeping I couldn't, right? Is that wrong too? Or maybe I am misunderstanding your distinction between idle and asleep?

Thanks again for the help here, guys. (I keep saying that, but I mean it!)

[xorlof]

Originally Posted by knc1

As long as the run time is only 2/11 of the 60 second interval, it will only add up to 2 hours of run time in the 11 hours elapsed.

Yes, my system will (generally) only be doing something for less than 5 seconds out of every minute. Touchscreen and home button should remain accessible to press 100% of the time though (like when reading a book).

Think that would work with the battery budget? 5 seconds per minute to do a screen update * 60 minutes per hour * 11 hours = 55 minutes of run time just updating its display. Add into that another 30 minutes total during the day where the users are actively looking up and entering information and you have about 1.5 hours of run time during the 11 hours if I understand what you're saying correctly.

[knc1]

Originally Posted by xorlof

Yes, my system will (generally) only be doing something for less than 5 seconds out of every minute. Touchscreen and home button should remain accessible to press 100% of the time though (like when reading a book).

Think that would work with the battery budget? 5 seconds per minute to do a screen update * 60 minutes per hour * 11 hours = 55 minutes of run time just updating its display. Add into that another 30 minutes total during the day where the users are actively looking up and entering information and you have about 1.5 hours of run time during the 11 hours if I understand what you're saying correctly.

Why don't you just try it and let us know what you found tomorrow?

[Cinisajoy]

Originally Posted by knc1

Why don't you just try it and let us know what you found tomorrow?

This is the best idea ever.

[xorlof]

Originally Posted by knc1

Why don't you just try it and let us know what you found tomorrow?

Ha! Because I haven't written the app and won't (it's reasonably complex) if I don't think this will work. However, I'm getting the feeling I may end up having to do what I wrote in my first post: "I could determine the answer to that question by making a dummy web app to try and mimic the approximate amount of cpu/screen refreshing that the real app would have, but if you all already know that my expectations are clearly reasonable or clearly unreasonable, that would save me a step." It sounds like there aren't hard and fast rules so I'm gonna have to put in the work. Darn!

Any clarification on the following? Because that makes a big difference in how I will approach this thing:

Originally Posted by xorlof

I understand that the display doesn't take any electricity except when changing its image, but I didn't understand that the device is completely asleep between changing book pages. I thought it was idling and only went to sleep when the screen saver kicked in. (Assume an unmodified Kindle here). If that's the case, how does the touchscreen and home button work when reading, but don't after the screen saver comes on. If they use the same power and there isn't a sleep mode where things are more powered down, it seems like you'd want to be able to use the touchscreen or home button to wake up the device. Is that just a UI decision Amazon decided to make?

Secondly, when is it not asleep then? I haven't jailbroken my kindle, but I assumed I could SSH into anytime after I "turned it on" but before the screen saver kicked in (even with a book image on display). If sleeping I couldn't, right? Is that wrong too? Or maybe I am misunderstanding your distinction between idle and asleep?

Thanks again for the help here, guys. (I keep saying that, but I mean it!)

[Cinisajoy]

I thought you already had the App and were trying to adapt it to a kindle.

Can I suggest you make the App, then go from there?

And yes, if you want to know if an idea of yours works and the experts aren't sure, you have to put in the work.

You just reminded me of my daughter.

[knc1]

Originally Posted by xorlof

Ha! Because I haven't written the app and won't (it's reasonably complex) if I don't think this will work. However, I'm getting the feeling I may end up having to do what I wrote in my first post: "I could determine the answer to that question by making a dummy web app to try and mimic the approximate amount of cpu/screen refreshing that the real app would have, but if you all already know that my expectations are clearly reasonable or clearly unreasonable, that would save me a step." It sounds like there aren't hard and fast rules so I'm gonna have to put in the work. Darn!

Any clarification on the following? Because that makes a big difference in how I will approach this thing:

That is an awful lot of questions and damn few line breaks. There is more electronics in the device than the SoC chip. That includes a low power micro-controller that watch the power button - among other things. Or you could start with the clock application to gain your basic measurements and then extrapolate from those. The screen saver is no indication that the device is asleep. "Idle" == No work to be done, as in "idle loop" (which in modern devices isn't a loop at all). "Sleep" == Read the ARM manual to see what that means - there are many individually controlled areas of the SoC chip. It is your project, who did you expect to do the work?

[xorlof]

No I don't want to put many, many hours into development only to discover it is useless because the Kindles can't handle it. I was hoping to be able to lean on experienced to developers to tell me if what I am trying to do is folly before I go and waste all that time.

The discussion has been battery heavy to this point to the exclusion of the other questions, but that's appropriate because if I have to somehow bring power to each location and to device (which is not an option in some venues where this system would be used) then most of the Kindle's advantage crumbles and a cheapo no-name 7" color Android tablet is probably superior to doing it on an eink device.

[Cinisajoy]

Ok here:
https://www.amazon.com/Malloom-Lipst...rds=Power+bank

Now you have power. Note: that is the cheapest.

I am sure several people have spent many many hours to discover the project turned out horrible.
Want to see a cross stitch patchwork cat?

[knc1]

Originally Posted by Cinisajoy

Ok here:
https://www.amazon.com/Malloom-Lipstick-External-Battery-Charger/dp/B01616XVPC/ref=sr_1_10?s=electronics&ie=UTF8&qid=1471569809&s r=1-10&keywords=Power+bank

Now you have power. Note: that is the cheapest.

I am sure several people have spent many many hours to discover the project turned out horrible.
Want to see a cross stitch patchwork cat?

I didn't know that lipstick needed to be re-charged.

I was selling those just a couple of years ago.
I also solar re-chargeable power banks.

[Cinisajoy]

Originally Posted by knc1

I didn't know that lipstick needed to be re-charged.

I was selling those just a couple of years ago.
I also solar re-chargeable power banks.

Only every couple of hours. More often if someone else is using your lips.

Hmmm. I don't have a solar power bank.

[Yourcat]

@xor: I have no idea whether meta refresh works in the kindle browser. If it does (or js.setTimeout) you may need just a simple to keep the Kindle alive by resetting the sleep timer and you may run your test with wifi enabled for some hours ....

[Yourcat]

"I haven't jailbroken my kindle, but I assumed I could SSH into anytime after I "turned it on" " - I hope you learned that JB is required for SSH.