1. Pierre van Mouche's Avatar
    I am building an application that collects RS232 data via USB. This requires the Nexus 7 to be rooted. No problem.
    The application will run 24 by 7 and therefore this means that the Nexus must be charged during operation.

    The Nexus 7 however used a USB charger which can only charge the device when beeing in slave-mode. Putting the device in host-mode also means that the Nexus will provide power to other devices in stead of use power to charge itself.

    I tried a lot but nothing really worked:
    - supplying power to pin 1 and 5 allthougt the Nexus was in host-mode
    - supplying power to the pogo pins
    - custom rom that stops the Nexus providing power while in host-mode - this worked, but it did not longer receive data via the USB port

    I tried another tablet (Yarivik 9-200 TAB) without succes - this tablet did not retrieve any data via USB/RS232. So I returned testing with the Nexus.
    Now I am thinking of removing the battery completely and provide power directly to the device itself.

    Is there anyone out there who already solved this problem? With software or hardware - I don't care, as long as it works.
    Recommendations for another tablet which solves my problem are welcome too.

    Many thanks !!!
    12-22-2012 11:44 AM
  2. Suntan's Avatar
    Any of the tablets that have stand alone, full size USB ports would be a place to look. Obviously any of the transformer tablets with their docks (the docks offer two usb ports) or possibly the older Toshiba and/or the Acer tablets.

    Otherwise, any android device with USB host support and a removable battery. Pull the batt and solder a filtered AC/DC inverter to the contacts...Depending on how "dedicated" you want to make it.

    12-24-2012 01:02 PM
  3. Pierre van Mouche's Avatar
    Hello Suntan,

    Listing some brands with USB host ports is great - thanks.
    It helps with part of my problem - selecting a device.
    My other problem is that some tablets provide a host port but still data-in via USB/RS232 was not succesfull. So far I haven't found someone who really is experienced in this area.

    Thanks again,
    12-25-2012 05:54 AM
  4. dark_samus's Avatar
    Could you supply power via the charger to the rs232 device while using the custom ROM mod? Meaning you don't power the tablet but the thing that would normally be taking the power from the tablet would that work? Or is that what you need foe it to take power only from the tablet

    Sent from my Nexus 7 using Android Central Forums
    01-03-2013 01:37 AM
  5. Suntan's Avatar
    Do you need this to be a tablet?

    Surely you can find one of the android-on-a-stick solutions that would be better suited. There are a multitude of dev box type android boards available. Surely if other people have wanted to do development work with serial I/O, it would likely be on those types of devices that you would find a conversation.

    Anything from the Cotton Candy or the MK802 to the Odroid-x.

    I have to ask though, if you're looking to build a custom app for logging serial data 24 hours a day, surely there are better platforms than an android based system. I know for a fact that people use little devices like a Raspberry Pi or even an Arduino board just to log serial data. Both of those have a fairly sizable development community with a lot of documentation (and even donated code) to get you up and running with routine stuff like I/O.

    01-03-2013 09:34 AM

Similar Threads

  1. Weather not working on charging dock
    By Theodore55 in forum Motorola Droid
    Replies: 9
    Last Post: 12-14-2009, 12:37 PM
  2. Independent charging
    By dancedirt7 in forum General Help and How To
    Replies: 3
    Last Post: 12-11-2009, 12:28 PM
  3. Slow charging on USB?
    By kehanra99 in forum HTC Hero
    Replies: 11
    Last Post: 12-05-2009, 04:02 PM
  4. Charging Eris
    By tmanrules13 in forum HTC Droid Eris
    Replies: 5
    Last Post: 11-19-2009, 09:35 PM
  5. Eris Charging and Battery Charging Dock?
    By cjohnson481 in forum HTC Droid Eris
    Replies: 0
    Last Post: 11-15-2009, 07:49 PM