Way of going to creating tablet from used tablets and conifguring boot - Page 1
Forum section: electronics / projects

author: UnruffledST
author_rank: Newbie
timestamp: April 30, 2017, 08:12:39 pm
content: So how would i go if i bought two tablets that are being sold for parts and wanted to use theirs parts to create a modified tablet of my own? What parts should worry about the most inside of a tablet when taking it out and wanting reuse it? I figure most parts are compatible from other tablets this be my first time doing something like this .Also what starting tools will be needed for taking a tablet apart and putting it back together ?

author: janoc
author_rank: Super Contributor
timestamp: April 30, 2017, 08:25:09 pm
content: Quote from: UnruffledST on April 30, 2017, 08:12:39 pmWhat made you actually believe this? Even obvious mechanical differences (size, mounts, etc.) aside, an iPad screen will certainly not fit any other tablet, not even another iPad model, for example. Different connectors are used, different pinouts, different electrical interfaces and the displays have often different registers sets/controllers.And that is only display ...Oh and the majority of that stuff is either undocumented or the documentation is not available without signing an NDA/paying a lot of money (e.g. MIPI for displays and cameras) or at all (especially Apple hardware). Good luck hunting for bootleg documents on obscure Chinese forums.Quote from: UnruffledST on April 30, 2017, 08:12:39 pmYou can find some good lists here:http://mendonipadrehab.com/Jessa runs an iPad/iPhone repair shop and her videos on Youtube explain a lot of how these devices work, even if you don't want to deal with Apple hardware.However, unless you buy two identical but differently broken tablets, your chances of getting this "frankentablet" to work are next to zero, especially with no background in electronics.

author: UnruffledST
author_rank: Newbie
timestamp: April 30, 2017, 09:42:39 pm
content: Ok thank you so much for replying and also I do have the opportunity to buy two identical tablets for really cheap also Im really looking more into android and not ipad since android is techinally more open than apple. Also is the signing that you are talking about for apple because I have heard of apple using signing restrictions when it comes to jailbreaking.

author: janoc
author_rank: Super Contributor
timestamp: May 01, 2017, 10:53:43 am
content: Quote from: UnruffledST on April 30, 2017, 09:42:39 pmThat "more open" part is really of no help here. That matters for companies building the products (anyone can take Android and make a tablet/phone), but from the consumer/repairman point of view it is very much the same thing. The moment you will need to modify firmware because e.g. the display module or wifi or camera or anything else needs slightly different settings, you will hit a wall.The firmware on all these devices is locked down (ever heard about "rooting" a tablet or phone?) and drivers for many things are binary blobs provided by the OEM to the manufacturer. Even company like Samsung may not have the source code and full documentation for e.g. the 3rd party camera module or radio chip/module their device uses. You will certainly never be able to (legally) obtain the required documentation or even the code itself as a "small fish", so even something as minor as upgrading a camera resolution by changing the camera module is pretty much out of the question.Your best bet is taking two identical tablets and replacing the broken parts in one with the good parts from the other one, assuming they are the same (may not be - even the same tablet model could have had several hardware revisions over the time). And then you pray that it will actually work. That's about all you can be expected to be able to do.I do wonder why are you attempting this - if your goal is to obtain a cheap tablet, go on on AliExpress and buy one - it would probably cost less than your two - three broken ones. And it would work, something which is far from guaranteed with your approach. Not to mention the amount of lost time.On the other hand, if you want to learn how to repair tablets, by all means, go ahead. Just expect to be very frustrated often unless you live in Shenzen or some place like that where you can buy replacement parts for almost anything in the street.

author: UnruffledST
author_rank: Newbie
timestamp: May 01, 2017, 11:31:00 pm
content: Quote from: janoc on May 01, 2017, 10:53:43 amOh ok thank you so much for the information I think you saved me a lot of time , I know you said that legally it isn't possible still there are ways I guess without getting the approval from a company like Samsung and yes I have rooted a phone , and yeah I guess telling you the end goal would help you help me understand better really I wanted to customize a tablet to be able to put pre installed systems on it and things of the sort and memory add ram basically create a super tablet of my own customization and as I understand you say that legally at the moment its not possible correct? Still it is possible illegally ? Say if it was to serve for education purposes only and such?

author: UnruffledST
author_rank: Newbie
timestamp: May 01, 2017, 11:32:51 pm
content: Also one of the main thing I wanted to do was run a system such as Ubuntu as the pre installed OS

author: cdev
author_rank: Super Contributor
timestamp: May 02, 2017, 12:34:26 am
content: You likely could build a tablet form factor pc using a Linux SBC, multi-touch screen, etc. Maybe that would satisfy your itch as it were, sounds in many ways preferable to android, except it would be a bit thicker. You could remove the parts that stuck out.

author: janoc
author_rank: Super Contributor
timestamp: May 02, 2017, 10:14:08 am
content: Quote from: UnruffledST on May 01, 2017, 11:31:00 pmI hope you understand that nobody would go on the record on a public forum to tell you where to obtain bootleg documentation or code. Nobody wants to get sued. So on that front you are on your own."Customizing" a tablet by changing the hardware is pretty much impossible job to do for a hobbyist. Even if you manage somehow to deal with things like BGA chips and package-on-package (good luck!), without having the corresponding drivers you won't be able to make the modified hardware to work.Quote from: UnruffledST on May 01, 2017, 11:31:00 pmForget it. You would be hard pressed to make even the bare kernel boot on most of the consumer hardware today. That something is capable of running Android doesn't mean that it runs stock Linux kernel. Especially ARM is an ecosystem where every motherboard is totally different, with board-specific hacks in the kernel to make it work.This is nothing like a PC where you have UEFI/BIOS, ACPI and similar things to bring up the machine, regardless of what is physically on the mobo. Here youmusttalk directly to the hardware to initialize and configure it - a famous example of this is the Apple SMC chip that controls power to the most of the system. Its programming is undocumented and proprietary - and without talking to it the motherboard won't even turn on. Most phones and tablets use similar solutions, because it simplifies (the often complex) task of powering up the system.If you want to try your hand building something like this, go rather with one of the Linux boards, as @cdev suggested above. Those are documented, there are plenty of accessories and the boards have tons of peripherals available. You have none of that on some random broken Android tablet that has been built down to a price without any regards for repairability, upgrading or public documentation - those machines are essentially designed to be disposable.

author: UnruffledST
author_rank: Newbie
timestamp: May 03, 2017, 06:28:51 am
content: Quote from: cdev on May 02, 2017, 12:34:26 amhttp://linuxgizmos.com/worlds-smallest-quad-core-sbc-starts-at-8-dollars/Ok so are you speaking on behalf of something like this? I notice that it comes without many features still that it is small so generally speaking I should be able to build a fairly slim and modern tablet?Also would this work silimar to Raspberry PI? I do not have much knowledge on it. I will have to do some research.

author: janoc
author_rank: Super Contributor
timestamp: May 03, 2017, 09:08:06 am
content: Quote from: UnruffledST on May 03, 2017, 06:28:51 amKinda sorta. If I was you I wouldn't focus on "slim" nor "modern" but learning how the system works and being able to actually make it work first. The smallest SBC boards are usually the worst/most difficult to start building from because of weird connectors and little I/O being available.Quote from: UnruffledST on May 03, 2017, 06:28:51 amNo, that $8 is an Allwinner machine, while it is an ARM the internals are totally different from the Broadcom SOC that RPi uses. Both run Linux but system configured for RPi will not run on the Neo. Also don't forget that the Neo is headless - i.e. there isno video output at all- no HDMI, no composite, no MIPI-DSI. So you wouldn't be able to connect a display to it. That board is meant to be used for things like a small robot or perhaps some networked IoT gizmo, not something the user can directly interact with.I suggest you start with Raspberry Pi, that has the best ecosystem (software, hardware and support) at the moment. That will allow you to learn the basics. Then you can "graduate" to something like a BeagleBone or one of the Chinese SBCs (OrangePi, BananaPi, the new Asus board, etc) where the learning curve is much steeper and support more difficult to obtain.Also, for something like a tablet you need to target a machine that has at least 1GB of RAM - e.g. that $8 Neo is next to useless with 256MB of RAM. You start Firefox or Chrome on it and it will crash because it runs out of memory right away. 1GB is minimum - it is still marginal, but it starts to be somewhat useable. Ideal would be at least 2-3GB. That rules out many of the cheapest boards. Another thing to look for is availability of hw accelerated drivers for the GPU - e.g. many of the cheap Allwinner-based boards are notoriously bad at this, because they use the ARM Mali GPU, for which there is no support. Without hw acceleration any kind of fancy graphics or video is going to be unusable.

author: cdev
author_rank: Super Contributor
timestamp: May 04, 2017, 08:30:28 pm
content: Yes, like @janoc stated there are compelling reasons to use something like an RPI if you plan on using graphics. You could remove some parts of the RPI to make it slimmer. That sounds like a potentially quite interesting build.

author: janoc
author_rank: Super Contributor
timestamp: May 04, 2017, 11:11:51 pm
content: Quote from: cdev on May 04, 2017, 08:30:28 pmOr just use the RPi Zero/Zero W, those are a lot smaller. However the problem will be RAM as those have only 512MB (and it is not upgradeable - uses package on package SoC+RAM combo).