This is a easy to assemble tablet that has an simple and powerful power system for usability and compatibility.
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Think of this tablet as not as some toy, but as a computer in whole. This Tablet is designed to be Modular by using USB as the main communications line. Though it is a modified version of USB so that way any one attachable card can be a power source, or be able to take control of the system. This is the PC-XT for the mobile world.
Youtube Playlist
I don't think it would be too healthy for someone to follow my projects too closely. I have a habit of running out of money, and getting 10 projects deep before I can come back to this. But, I think I have something I can gnaw on to help this happen. Firstly, someone has gone about and created an open source cellular telephone. If they do release anything I can use their dev board with the power system that I have designed to make something of this.
The other thing is the operating system and main controls for the system. I am hoping to make the basic controls for this system as free as possible. That means open source hardware when and if possible. The prototype will not be pretty, but it will be functional. After the prototype is made, I may drop this project entirely. I have been mauling over this from time to time since highschool. There are too many obsessions and too little time.
There is a hope that this is the last of the project updates that aren't showing progress. Otherwise this account is a waste of space and time.
These past three months have been insightful. My dream project has been on the forefront of my mind for 4 years now. While waiting for Google to do something it has given me a 3 month reprieve of not even looking at this. I have had time to pick up an internship, and now I am working to get a new job at a data management group. I have put more time into my studies without distraction. And, I have cleared all my thoughts on the matter. I haven't been able to fully make a working color model for the 3D printer so my attention is back to here.
When I was last doing this three issues had me terrified: design of the logic system, the creation of the computing card that controlled the system, and feasibility of the build with so many esoteric connections and design philosophies. Now, I am back with a solution and a goal that I will not let budge one millimeter. In the logic system I was terrified about who had control of the logic over the USB and video. I now know I will be pushing almost all control logic down USB since its standard has now expanded to a 10Gb/s standard with a glimmer of 20Gb/s out there. Which means I can push all video data down the USB line without denying most other things on the bus. Even 4k won't go too far beyond 6Gb/s since it's bound by SATA III under most circumstances, and I don't have any expectations that this is the immediate use. Another huge thought on the matter is that it leave a possibility of multiple host computing devices on the same tablet working in tandem as master and slave.
As for designing a computer card for the tablet... I'm not even going to think about it. That's because it takes a team of people to make a proper board, and it's design won't make or break this project.
I can have a board that can without making the Motherboard for the mobile system, but I can't have the modular tablet without the power system and logic. So, that's off my dinner plate, and instead I should be focusing on drivers for *nix like and maybe NT to drive the entire board and establish the controls.
And with almost exclusively using USB 3.1/C for my logic interface, I can make the production for anyone who wants to build this feasible. I can take all proprietary connections and reduce them to a type C connection and maybe headers for SPI/I2C for some rudimentary things to maintain control. IF done right though, there should be an internal host that hands Bus control over to the proper device without the need for SPI/I2C. This would eliminate all but one connection type, and that type would just be USB.
Since I made those "simple" things out, I can make goals that will be done this year:
It's not that I'm not enjoying making this project, but I want to put a hold on this project on hold until I fully see how the Ara project is coming together. Since phone blocks is something that put the tile format into this design I want to see how this pans out. I might pop on down to pick one up to see the phone in person from Puerto Rico if/when they're released since I'm in the American South. I will try to learn from what they're doing and see how I can apply it. If they publish greater details on the internals I might shamelessly lift the tech and transplant it here.
I'm Not normally into making quick updates, but I have updated the schematic to be a little more in line with what I was thinking. When I went through the caves for a good ideal diode I found I could replace quite a few parts in one go. Most of the darlington PNP transistors can be removed, and almost all the protection diodes could go since their voltage drop would most likely push this out of spec, and all those devices functions was covered by this singular chip. It can carry 2.6 amps, and it's dropout voltage is lower than the diode and the transistors. The schematic looks off in my head. It's like there are too many parts between the boost converters and USB ports, but I will figure it out. I didn't bother mucking with the microcontroller and logic circuitry. I just made a point it exists with the 3.3v regulator. I will try to run a simulation on this before I order it.
***ERRORS***
I will have to post a new circuit.
It's not pretty by most senses of the word, but it's almost ready to get moved into KiCAD for a proper layout. This isn't everything that I wanted, but it's what I needed to make this power system function* enough for a test. After about 5 iterations this week, I have come to this design. All the tags on the page go to the Micro Controller. The USB should support two way power systems, and there is plenty of battery power for the system without the exterior batteries. I have put up safety guards for the power and data lines, set up the shield and made the boost converter rail diagram for the BABP (Big alternative battery pack).
I have added some design rules to the tablet.
Some interesting things cropped up as I added control transistors to stop and allow current flow. I didn't notice it until I began writing it, but I could increase efficiency by attaching sensors to the boost converters, and turn them on and off by how much current is going though them at any moment. Too low it gets turned off. But, that will have to be added in a later edition of the bridge board. Also, all the diodes that you see are to represent ideal diode circuits. I haven't picked out which one I am going with yet.
As for now I can label the unlabeled components, test the design (if ltspice has all the components. Otherwise I will just have to test small fractions of the circuit), put it on a board schematic/gerber file, and prep it to be ordered from OSH Parks.
After four months of continual silence from life getting ahead of me, I have had a chance to sit down and truly figure out what the platform will be based on (who got knocked out by me being in the quarter finals even though I resigned?). I had my original mind stuck inbetween a particular ARM SoC and Intel Atom SoC. And, with much deliberation and one trip to see how easy it is to purchase each of these processors it was an easy decision. Intel seems to be the winner right now by a land slide. This is because I can purchase most intel processors, scan the bottom and map out the bga on my ridiculous scanner, and I don't have to go through a paper wall to get the processors. Not one ARM Cortex-A model was quickly available from any of the manufacturers. Well, at least I can put all my ARM assembly into the Raspberry Pi. ***I should have been focusing on *nix like Kernels***
Things to do now is send my power system design to OSH to get made, and have it sent back with a screen so I can do the soldering here (I DON'T HAVE TO USE MY TRANSPARENT LASER PRINTER SHEETS FOR SILKSCREEN :D). I need a test subject for the new reflow oven, and three of those boards would be great.
Write 2 versions of the drivers to control the main power control on the board. One practical prototype for the Pi, and one for the x86_64 design (If I hadn't looked at ARM I would have went for x86_64 sooner.... this is madness... we all go a little mad).
Next up I need to use my Pi as a test dummy to run the embedded USB 2.0->1.0 Hub and the power supply. I need to make sure that those things run correctly, and I might run video if I want to make a sample board that is 4 layers that separates power, signaling, video, and more.
Once I have all that working, and I have proper power system I can tackle the real beast. the 4+ layers of the final power prototype, and the 4+ layer mainboard prototype. I will be sacked studying every detail for a few months to a year. My lab* at that point will have to be rebuilt from the ground up. There will be minimal margins of error, and every error will easily cost me weeks.
Also, pictures, video (4K), "documentation", and giveaway prototypes when all is said and done (depending how much I hate the project when I get to my goal... More I hate it the more likely I will give away prototypes and not make more). If, I give away prototypes they get sent to these people first.
My friend who helped me get started by building my initial lab with good equipment.
UXWBILL
Mystery Person
Dave Jones
Myself *why so low on the list me* -because you build bad things and should feel bad
Now, I can get down and refine what my image on what the specs have a good chance of being.
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Power system will be based on a TI chip, and will be controlled by saved settings in the OS. The device defaults everything to on until a boot sequence tells it otherwise. This controls the distribution of power to all the individual segments on the device, it can't control the power of the main board, switches between charging and charged circuitry, and performs the first power on test then passes this onto the main system. That way you can upgrade and replace the main system without the power on sequece being completely in control of the main device. This also informs the main computer if a device is disconnected after all power has been removed from that device.
*Also, the charging port will be on the oppisite side of the board of the main control logic of the power/video/usb.
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Each segment will have each device connect via a friction connection (think game boy, sega, and nintendo cartridge). This seemed like something that would last a considerable amount of time, be simple to produce, and easy to use. All other solutions required too many tools. Power will be turned off by definition of the user. Not only will there be usb connections...
Read more »The last parts listing that I had were not as good as I hoped they were. Since I was a little more patient in the design out of laziness I saved myself a little trouble in making the proper power system. I have effectively replaced the MAX618 with the TPS81256. This has opened up a new series of possibilities because it also possibly eliminates the need for regulator pairing. This gives an absolute level of control over each connected device and allows me to have a surprise set up in the design. All I have to do now is order some COG/NGO ceramic capacitors. This will allow me to finish getting the parts I need for the test system, and it will also allow me to spend time troubleshooting certain persistant problems.
I was a bit worried when I was overviewing my parts list for the schematic of the power supply, and now that I have slept and began working on the reflow oven my worries were right. I have gone back and overviewed my power system and... it's wrong wrong wrong wrong... Continue Briefly Here→
I have come to the conclusion that only large updates should be focused on here. Small updates like the one that I have today will be relinquished to the blog. This isn't because I don't want to keep everything in one concise place, but it is instead due to how HackADay has set up the projects page. I will try to build a greasemonkey script to adjust how my page looks to anybody who can get it. These two ideas will allow me to run updates the way I need to. To read the full update go here.
TLDR:
Got the parts that I needed for the oven with a few extra and some not ordered. I have decided to lower the space with insulation and a fan, and I corrupted a μC so procrastination on selling a computer saved me because it's the only one with a proper serial and parallel port.
I am adding something to my portfolio when building this that probably should have been added a while ago. I am building the communications schedule for the USB setup. I am using http://www.usb.org as a base site to collect some of the specifications and the checklist on prepping the USB for work.
The parts for the reflow oven are now officially on their way, and they will arrive in due time. Here are the parts that I ordered/using.
Crydom D2425 (arrived)
ATMega328
2 22pf ceramic capacitors
16MHz Crystal
Button Switch
Radio Shack Perfboard (here)
Repurposed Heatsink
14g Wire (here)
16X2 Display
I have also decided to keep a rolling playlist in the description. I will take note of updates in text, but most updates will occur in the video playlist.
Krinkleneck
Rob Lauer
Yonghan
Clara Hobbs
Yaroslav Zhilin
By August 20th you must have the following:
- A video. It should be less than 2 minutes long describing your project. Put it on YouTube (or Youku), and add a link to it on your project page. This is done by editing your project (edit link is at the top of your project page) and adding it as an "External Link"
- At least 4 Project Logs (you've got this covered).
- A system design document
- Links to code repositories, and remember to mention any licenses or permissions needed for your project. For example, if you are using software libraries you need to document that information.
You should also try to highlight how your project is 'Connected' and 'Open' in the details and video.
There are a couple of tutorial video's with more info here: http://hackaday.com/2014/07/26/4-minutes-to-entry/
Good luck!