Is this a crazy idea or not?

[xorlof]

Hi all. I'm new here, but it looks like a great thing you all have going! Anyway, I'd like to bounce an idea off of all of you Kindle experts and see if you think it sounds reasonable (i.e., can the Kindles handle this).

Basically, I'm hoping to be able to hack a bunch of Kindle Touches to run a full screen web app (custom written for the kindle) on batteries for about 11 hours a day (screen saver/sleeping turned off). 95% of the time during the 11 hour time period, the Kindle would act as a refreshing informational display. Once a minute (ideally...but can be every 5 minutes if necessary to save batteries), the Kindle would contact a local web server to get information and do a cpu-lite refresh of its display. The other 5% of time there will be user interaction with the web app. Nothing computationally expensive, but during this time there would be some wifi traffic and page loads.

So question #1 is do you think that 11 hours is a reasonable-to-expect battery life? 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. I have a feeling my expectations may be borderline here (and thus might have to test to be sure). Please let me know!

Batteries aside, I know I could write the web code needed and think I can handle enhancing K5 WebLaunch in way to make the software actually run on the Kindle with the desired additional features. However, I don't know what I don't know about the Kindle platform as a whole, if that makes sense. If you could give me some heads up on things I should be aware of--gotchas or pitfalls for this type of application--that would be awesome, and please consider that question #2.

Finally, regarding enhancing WebLaunch, which I just mentioned, that leads to question #3: anybody see any obvious issues to me eventually being able to figure out how to add the following functionality?
- Ability to launch the app so you hold the kindle in an upside down orientation.
- Ability to either block or (even better) remap the home button.
- Ability to play sounds. (In my case, a short "ding" type clip to attract attention to the display a couple of times an hour.)
My rudimentary understanding is that there are Pillow/LIPC calls that could be used to make those happen, right?

Thanks in advance, and apologies for the long post! If you're curious as to what all of this would be used for, check the spoiler. *I* think it is something cool.

Spoiler:

Basically we run tournaments for this cool board game (semi-random picture from a recent event):

[Image violates Posting Guidelines for size - MODERATOR]
Smaller image:


The tables would usually be full (this was a slow time), but you get the idea. Picture several dozen people playing that miniatures game simultaneously. Each individual board/map would have one kindle next to it in a stand and would perform the following functions to help us run the tournament.

• list the map number of that station
• at the start of a round, every kindle would list the pairings for all maps ("Player A vs Player B on map 1", "Player X vs Player Y on map 2"). You consult any kindle at the beginning of the round find out where to go/play for that round.
• provide information about the details of the current round in the tournament (time limits and such, who is playing at this station),
• provide certain useful game-related reference information plus details about the map the players have in front of them (e.g., allowed areas on that map where they can place their armies at the start of the game, etc.),
• provide a timer for how much time remains in the current round
• provide browseable tournament result information (for following along how other friends are doing during downtime if you finish your game early)
• would be what the players use to send the results of their game (who won and some other details) back to those of us running the tournament. The game results would then be used to determine correct Swiss style pairings for the next round of tournament, eventually leading to identifying our winners.
• provide a button to call a referee over for a question or ruling
• might (this is lower priority) also be used to register yourself for the various tournaments we run through the day (you have to provide information on what figures you are using in your army and it could check to make sure it meets the requirements for the rules of a particular tournament). The idea behind this last one is that there is time between one tournament finishing and the other starting. Players could just grab any available Kindle and register themselves instead of us (the organizers) doing it at our main computer, which is a bottleneck.

The above system, if it works, feels pretty slick to me. It would help with getting game information recorded accurately and round/map information distributed quickly and widely. Depending on the tournament format, games getting called on time (running too long) can be an issue and when there is a lot of that, it threatens to make the schedule slip. Finishing one round on time and getting the new set of parings determined swifty (which this whole system would REALLY help with) helps things run on time which makes everyone (players and organizers) happier.

BTW, we're all just fans of the game. Nobody is making money on this. I have the chance for a screaming deal on the Kindle Touches so hope to determine if this is feasible pretty quickly while I can still get the deal. Even with the deal this will still be pretty pricey to put into play since we're talking about a lot of Kindles.

[Cinisajoy]

Not sure about the second part.
You said checking the internet once a minute.
At best, that would drain the battery every day.
Even at every 5 minutes, at best you might get 3 days of battery life.

Refresher on Kindle battery life.
That one month of battery life you have read about is based on reading 30 minutes a day with the wifi turned off.
So battery time is actually only about 15 hours under those conditions.
Wifi constantly on, cut the time to 10 hours.
Wifi pretty much constantly checking time will be at best 7.5 hours.

Yes, I know the ads for battery life are a bit misleading.

[Cinisajoy]

Now that game looks like H G Wells war games. Except modernized. Totally cool.

[Cinisajoy]

Also which kindle are you thinking of using?

[knc1]

Depending on the model of the Kindle and what communications you have enabled, the battery run-time is from 2 to 4 hours.

or as you describe it;
2 hours running, 9 hours asleep out of every 11 hours.

[Cinisajoy]

Originally Posted by knc1

Depending on the model of the Kindle and what communications you have enabled, the battery run-time is from 2 to 4 hours.

or as you describe it;
2 hours running, 9 hours asleep out of every 11 hours.

He said he wanted it to check something every minute or every 5 minutes. So where are you coming up with 9 hours sleep time?

I think we need to know how many seconds each check and update takes.

[xorlof]

Thanks for the initial feedback. Much appreciated Here are some answers/clarifcations. For devices, I am talking about the Kindle Touch (1.0). Why that model? Three reasons: 1) most importantly, I can get them cheap (with good battery life remaining), 2) it has a touchscreen so I can make an interface people can easily pick up and use, and 3) it was one of the last Kindles to have a speaker which I'd like to briefly use for the app.

Regarding battery, this was my thinking:

Kindles are conservatively (?) rated at one month of battery life at 1/2 hour of reading per day. It seems like you can hit that number even with wifi on. (Some ads from the kindle 3/4 era say 2 months after the Nook started making that claim.) So that is conservatively 15 hours of non-sleeping time, with the screen probably updating about once a minute. I'm hoping to hit 11 hours, which sounds easy enough (4 hours less than 15), but the devices I'd be using don't have brand new batteries (the batteries are in good shape though) and I'll be using Wifi. That's why I was saying I thought 11 hours might be cutting it close.

You asked about how long it takes to do the update? It will be contacting a local, non-overloaded web server retreiving small data sets, so I'm guessing less than a second to get the data. And I'm guessing about a second processing and displaying the data, even on the Kindle's reasonably slow processor. It's very straightforward in that regard. (The majority of per-minute updates will return no new data relevant to the currently active screen in the web app, so the only screen update will be to update the minutes-remaing-to-play-out-the-current-round countdown. After it's done displaying the update the cpu should go back to idle (or at least my web app won't be doing anything until the next per-minute update).

I don't want the device to ever go to sleep during the whole event though because ideally I want a person to be able to pick up the device at any time and interact with the web app--no "press power button to wakeup" instructions needed. This interaction time should be short--probably only in the range of a half hour total for the whole 11 hour day. I would recharge the Kindles each night.

Does that make sense?

[Yourcat]

I'd expect 1-2 broken or lost Kindles during each tournament day. Do you plan to use them each weekend?

I like the idea to aid the players and to allow them to submit their data on their own. Based on what I know right now about your plan I'd avoid implementing it requiring Kindles.

In any case you need a central application to handle the data. You need to setup a private wifi - this could be an issue if you have a lot of clients/data. And you likely need to provide USB charging slots.
It will be 'net' based as you plan to use wifi. It may be more easy to build a web application so the users may use their own smartphone browser to get the data.
I know the display is smaller but you could run the web app also in a Kindle or Kobo browser if available - so it would be completely device independent. And for finals you may use a 4K screen and show the browser/web UI there.

[Cinisajoy]

Makes perfect sense.

[knc1]

Originally Posted by xorlof

- - - - -
Kindles are conservatively (?) rated at one month of battery life at 1/2 hour of reading per day. It seems like you can hit that number even with wifi on. (Some ads from the kindle 3/4 era say 2 months after the Nook started making that claim.) So that is conservatively 15 hours of non-sleeping time, with the screen probably updating about once a minute. I'm hoping to hit 11 hours, which sounds easy enough (4 hours less than 15), but the devices I'd be using don't have brand new batteries (the batteries are in good shape though) and I'll be using Wifi. That's why I was saying I thought 11 hours might be cutting it close.
- - - - - -

What was your point in asking the question if all you are intending to do is dispute it?
It does not make anyone willing to take the time to answer your next question(s).

Rethink all of that -
Your rationalizing without any facts, only marketing statements.

Other than that, the error in your thinking is that the Kindle does not shift to a low power mode between page turns.

The only time the Kindle is actually 'running' is during the changing of the display.

[xorlof]

Originally Posted by knc1

What was your point in asking the question if all you are intending to do is dispute it?
It does not make anyone willing to take the time to answer your next question(s).

No, I didn't intend any of that to dispute anything you guys wrote. Sorry if it came off that way. There were questions about specifics such as "number of seconds in each check and update takes" and the numbers supplied by you and Cinisajoy didn't definitely confirm or refute that the battery could hold up (assuming I was reading them correctly), so I was trying to clarify my thinking and provide more detail as to how hard I'd be running (or not running) the display and CPU.

I'm hoping you can help me take that detail and apply it to your knowledge and experience. You mentioned:

Originally Posted by knc1

Other than that, the error in your thinking is that the Kindle does not shift to a low power mode between page turns. The only time the Kindle is actually 'running' is during the changing of the display.

Right, but even if I'm not updating the display I can be hitting the CPU pretty hard between display changes...or not! While I don't have knowledge about the kindle devices, I do have knowledge of programming mobile devices, and if I am 100% of the time pegging the cpu at 100% on any mobile device even if nothing is happening on screen I know I'm going to suck A LOT more battery than if I don't use use the CPU much. The CPUs use more power when they're being worked. That's the power savings I'm talking about (only using the CPU a few seconds every minute), not a power savings from the device dropping to a greater sleep mode (normally screen saver time).

I think that's what you were getting at when you wrote this: "Depending on the model of the Kindle and what communications you have enabled, the battery run-time is from 2 to 4 hours. or as you describe it; 2 hours running, 9 hours asleep out of every 11 hours." Just to clarify and be sure: does that mean if I'm running my Javascript and web page repaint for less than 2 hours of CPU time before recharging, and the rest of the 11 hour block time I have the device sitting idle (but NOT have the Kindle in sleep mode), I'm probably OK? Pardon my denseness, I'm just trying to parse your information correctly!

Originally Posted by Yourcat

I'd expect 1-2 broken or lost Kindles during each tournament day. Do you plan to use them each weekend?

Thanks for checking in on the theft issue. My post was getting long so I didn't go into all details of my plan, but I think I have "loss prevention" covered. As far as breaking, yeah that still could be an issue...

No, these wouldn't be used each weekend, but if all goes well I hope to have them see regular use.

Originally Posted by Yourcat

In any case you need a central application to handle the data. You need to setup a private wifi - this could be an issue if you have a lot of clients/data.

Right, I have a setup I've already done for a different project that I can apply to this one. It is basically a pretty nice consumer wifi router, running custom software. Connect the kindles to that router and try to open up any website. It will instead pop up with the web app I need the kindles to run. The web server and web app run on the router itself! All you need to do is plug the router into electricity. It doesn't have to connect to any outside network at all.

Originally Posted by Yourcat

And you likely need to provide USB charging slots.

Yeah, that's what I'm hoping to avoid and trying to live within the Kindle's battery budget, but am not sure if I can!

Originally Posted by Yourcat

It will be 'net' based as you plan to use wifi. It may be more easy to build a web application so the users may use their own smartphone browser to get the data. I know the display is smaller but you could run the web app also in a Kindle or Kobo browser if available - so it would be completely device independent. And for finals you may use a 4K screen and show the browser/web UI there.

I appreciate the brainstorming and if doing the custom wifi router system, nothing would stop anyone from connecting to that router and using their smartphones. This could happen whether or not we have Kindles onsite for screens. I have reasons for preferring the Kindle solution vs. a "bring your own smartphone" solution and can go into that if you're curious!

Thanks again all!

[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?

[knc1]

Right, but even if I'm not updating the display I can be hitting the CPU pretty hard between display changes...or not!

That is in your case.
But the basis being used is for the purpose of reading a book.

Which was my point - you where mixing Apples and Oranges in your reasoning.

Just to clarify and be sure: does that mean if I'm running my Javascript and web page repaint for less than 2 hours of CPU time before recharging, and the rest of the 11 hour block time I have the device sitting idle (but NOT have the Kindle in sleep mode)

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

[Cinisajoy]

Originally Posted by knc1

That is in your case.
But the basis being used is for the purpose of reading a book.

Which was my point - you where mixing Apples and Oranges in your reasoning.


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

If I read it right, he wants to change the screen every minute.

[knc1]

Originally Posted by Cinisajoy

If I read it right, he wants to change the screen every minute.

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.