Tablet suggestions 7" or 10" ?

Discussion in 'General Electronics Chat' started by THE_RB, May 2, 2014.

  1. THE_RB

    Thread Starter AAC Fanatic!

    Feb 11, 2008
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    Hi, I'm in the market to buy a tablet.

    I don't care about internet connectivity or processing speed etc.

    The important thing is that it can be used as a display device, to communicate with small PIC microcontroller devices that I will make myself.

    So these are the most important specs;
    1. must have card socket so data can be stored to SD card etc.

    2. must have USB host ability, so it can connect to a PIC via USB cable and USB->TTL serial converter etc.

    3. inbuilt bluetooth would be nice, so it can connect to a PIC using a second cheap ebay bluetooth module at the PIC end.

    4. ability to write software for it. I want to be able to write simple apps to chart incoming data on the tablet's screen, or display messages showing incoming data and warnings etc. Obviously I don't want to have to buy a compiler to do this!

    5. NOT Apple or Windows monopolies please!

    If anyone has tablet suggestions I would be very appreciative. :) Especially if you have had experience programming a tablet in whatever language and/or connecting it to real world devices.

    Price is always an issue of course, I don't want to spend $500 if I can get something almost as good for $200.
    :)
     
  2. alfacliff

    Well-Known Member

    Dec 13, 2013
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    most important, who are your eyes?
     
  3. MrChips

    Moderator

    Oct 2, 2009
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    You and I must be working on the same projects.

    I started may moons ago with a Palm Pilot and RS-232 connectivity. Tablets have come a long way since then. For connectivity, we can choose from the following:

    RS-232
    RS-485
    IrDA
    USB
    Bluetooth
    ZigBee
    RJ45 ethernet

    So far I have considered the following:

    Raspberry Pi
    ARM9BOARD OK210
    STM32F429 TFT LCD
    Samsung Galaxy
    Google Nexus
    and so many Android tablets under $100 - hard to choose one.

    As you know, I have my own VGA system now running from an STM32F407, but displays in monochrome only at the moment.

    One capability I would like to have is the ability to run MATLAB scripts or Octave.

    Keep me informed with your quest.
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I picked up a 10" Visual Land for $139.00, comes with Android O.S. it is a fairly decent pad for the price.
    Android is Linux based, so essentially open source.
    Max.
     
    Last edited: May 2, 2014
  5. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    Not sure how you're gonna write code for an ARM processor without a compiler...

    ak
     
  6. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    I don't have any experience, but I am cheap. Have a look at the ad I just got in the email.
     
  7. alfacliff

    Well-Known Member

    Dec 13, 2013
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    I have a couple of Dell Axium pda's. they have usb, ir, and one has bluetooth and other rf connectivity. with over 400 mhz processors, full color twist screens, and other nest stuff, they were a good deal at only about 10.00 each. tunning windows ce isnt mch of a problem, I found several ham radio programs for them and interface cables for lots of modes, like rtty, psk31, cw, and others that can be both sent and recieved using the internal sound board interface. the only probloem I have with them is I havnt found a way to save programs on the sd card built in.
     
  8. THE_RB

    Thread Starter AAC Fanatic!

    Feb 11, 2008
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    HOW are my eyes? I assume you are referencing the 7" vs 10" screen size decision? Good point, after looking at some ads and reviews I've pretty much settled on 10". :)


    Yeah I remember that VGA discussion! I went the other way and have been buying 4.2" and 7" colour TFT displays from ebay and have been driving them with PICs. I can get a nice display result but at a cost of lots of wiring and messing about etc.

    And larger displays are still not cheap, surprisingly since you can buy devices with large displays in them cheap! (Like Tracecom's ad!)


    I can tell you're not a programmer! It's all in the syntax; "I don't want to BUY a compiler". ;)

    My woman seems set on the Samsung Galaxy 10" that has Intel atom CPU, USB host, and bluetooth. They are about to release the v4 any day so the v3 models are clearing out cheap locally.

    So my new question becomes; does anyone have suggestions for programming it?

    Basically I have two options;
    1. Get a free compiler and make executables, possibly on my PC, which I can then put on SD card and run on the tablet under Android (jellybean i think).
    2. Use python or other interpreted language and have it running and interpreted on the tablet under Android. Then I have to have the source code on the tablet, which is less secure and less convenient for code editing.

    Or any other suggestions? I'm all ears. :)
     
  9. nerdegutta

    Moderator

    Dec 15, 2009
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    How about BananaPi and Beaglebone?

    RB: Have you tried Eclipse?
     
    Last edited: May 3, 2014
  10. THE_RB

    Thread Starter AAC Fanatic!

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    Hi Nerdegutta, I had to google "eclipse" and think you are referring to the 7" 3G tablet named "eclipse"?

    We bought a Samsung galaxy 3 yesterday from a local shop. More expensive than online but with the local warranty support etc.

    I really like the hardware, really nice screen, gps, wifi, bluetooth, USB host port, IR, dual cameras etc.

    I'm less impressed with the out of the box functionality. It has GPS hardware but no app, the only thing it has is google maps and that needs to be online to work. I'm not sure what the value of a GPS is if it only works when you're in the city sitting at a wifi hotspot. Personally I would have liked to use it out in the field somewhere... ;)

    Likewise the IR remote control software doesn't work, needs to be online. Probably a registration thing. I hate online registrations with a vengeance. Just give me software that ALREADY works, thank you.

    Anyway I'm still looking for the best (easiest?) way to get some programming functionality where I can make it receive, record and display/chart data coming in one of the ports; bluetooth/USB/IR.

    I'm hoping someone here writes apps or interpreted BASIC/python stuff on their tablet. :)
     
  11. Brownout

    Well-Known Member

    Jan 10, 2012
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    Good choice. We really like ours, use it mostly for navigation. We have mobile 4G, so staying connected is no issue. I've not tried to write any programs yet, but I'll be watching this for ideas.
     
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  12. nerdegutta

    Moderator

    Dec 15, 2009
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    I was referring to this. The IDE. http://www.eclipse.org/resources/resource.php?id=539
    (This is just a example).

    Download link. http://www.eclipse.org/downloads/
    My cellphone has a Wifi hotspot function. When I enable it, my GF can surf the web with 4G, through my phone. I have a Samsung cellphone.
     
    Last edited: May 4, 2014
  13. Markd77

    Senior Member

    Sep 7, 2009
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    In google maps go into the search box and then scroll down, you should see something like download map area.
    Android IDE:
    http://www.android-ide.com/tutorials.html
    Might do what you want, worth a look.
     
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  14. sirch2

    Well-Known Member

    Jan 21, 2013
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    I've done some Android development for my phone, turned out not to be too difficult after the initial learning curve. The phone had bluetooth so I used a bluethooth-serial module to communicate from the phone to an external processor. Like nerdegutta says, download the Android SDK and the Eclipse IDE, it uses what is essentially Java as a language.
     
  15. THE_RB

    Thread Starter AAC Fanatic!

    Feb 11, 2008
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    Thank you Nerdegutta for the eclipse link. Sorry for my confusion. :)

    To Sirch2; good to hear from someone who has done some Android development. I've done java coding for web page online calculators and stuff, and it was easy enough.

    I think you will be right about the "initial learning curve" being tough though. I've never used Linux or its brethren so I have to start right from the start. Hopefully my many years of dos/Windows app developing will count for something... Crossing my fingers. ;)

    There's no rush on this as I'm busy with commercial stuff at the moment and this Tablet is a hobby level project. Long term i hope to be able to use the tablet to display/control devices around the house, including my homemade CNC and Pick'n'place machines etc.

    It would be nice to be able to buy those <$50 ebay tablets and use them as machine controllers or terminals. :)
     
  16. Markd77

    Senior Member

    Sep 7, 2009
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    Maybe you can use a Beadleboard or Raspberry pi as the interface and a tablet to control it
     
  17. sirch2

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    Jan 21, 2013
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    The SDK and associated libraries isolate you pretty much completely for the underlying Linux so I wouldn't worry too much about that. The thing I found a bit strange was that the UI, menu options and various other things are defined in XML files which you can then access from code. So you end up with a mix of tings in XML files and code.

    Interacting with sensor, bluetooth, storeage, etc. was all pretty straight forward and there are good examples with the SDK and good on line help.
     
  18. THE_RB

    Thread Starter AAC Fanatic!

    Feb 11, 2008
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    I'm hoping to use any PIC and USB->TTL serial module, or a bluetooth module. I can get those modules very cheap from ebay.

    Is there an advantage to using a Beagle or Pi? Maybe they have internal WiFi or something that will interface directly with no other hardware required?

    Generally I want to have other hardware as there will be real world sensors and motor drivers etc, so the PIC hardware part is convenient for that (and i can do it with my eyes closed these days).

    Thanks again! That sounds good. :)

    Hopefully there is good OFF-line help too, as my coding PC never gets connected to an internet! Scary thought. :eek:


    (edit) just a bit off topic, how the heck do you put a file (or shortcut to a file) on the desktop (home page) on an Android tablet?

    I want to put commonly used file like some PDFs on the home page. At the moment I am looking through the directory structure each time I want to open a file! Darn tablet noob.
     
  19. sirch2

    Well-Known Member

    Jan 21, 2013
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    I think it is down to the file explorer app you are using. ES File Explorer has an option to do this, long click on the file, then choose more on the options and that has a Add to Descktop (or something like that). There is also "File Widget" but I haven't tried that.

    The issue is that the Android UI is not like Windows (or one of the Linux windows managers), it was designed for small displays and "limited" processors and so really only expects Apps or Widgets on the Home Screen. It then expects the App to find and display the files and other resources it uses.
     
  20. Markd77

    Senior Member

    Sep 7, 2009
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    You can plug a USB WIFI dongle into the Pi or Beagleboard, or they can plug into ethernet. They also have a few I/O pins, the PI has 17, some of which can be used for SPI, I2C, serial, PWM.
    Maybe not as good as a PIC for realtime things, but for robot control they might work well.
     
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