I am looking for a cheap 7" Android tablet to connect via Bluetooth with and Arduino. Has anyone tested any of the tablets available on ebay or DX?
My idea is to use a $75 tablet as the brain and the Arduino to interface with Sensors, either via ADK or USB-serial, and I would appreciate some thoughts on that.
However, I spotted a few potential problems below:
Cheap tablets have no Bluetooth. Can I use a bluetooth dongle? I've heard their USB is not powered, which could be an issue.
Only one USB port, which would occupied by the Bluetooth dongle. Is a USB hub an option?
Rumors that this tablets are unstable when connected to the charger.
It probably depends on what version of the Android OS the tablet is running, and whether you can root the tablet (to install custom versions of the OS). I suspect you want a tablet with using the Android OS Ice Cream Sandwich (ICS, 4.0) or Jelly Bean (JB, 4.1). If your tablet is running ICS or JB, it has the option of wifi-direct, which means you could set up a connection to the arduino using a wifi shield without having a wifi infrastructure present.
There is the head phone (3.5mm) jack, though I've seen in other projects that there delays in sending out information via the headphone jack that matter for high speed devices, but may not matter for normal stuff. Also, Android devices meant to be sold in Europe have volume limiters that may make programming harder (this comes from the triggertrap device, which had some interesting quirks when they released the Android version using the phone jack that they didn't have on the iphone).
A wacky way if you are controlling the s/w on the android is to dedicate part of the screen to the communication, and tape a color sensor over that spot, and when you get a particular color, use it to do something on the arduino.
slayer3031987:
"If you are looking for a cheap but good quality tablet, I would recommend uPlay C70 from uPlay Tablet (www.uPlayTablet.com) for only $79. This is the latest model from uPlay (a Silicon Valley company, located next to Apple) for the Christmas shopping season. It's running the latest Google Android 4.0 ICS, has a powerful ARM based 1.2GHz CPU with GPU, capacitive multi-touch screen, front-facing camera, expandable memory, and HDMI port to output video and game to your big screen TV. uPlay is the leader of high quality low price tablet. They have tablets similar to Apple iPad and Google Nexus 7 but half price. Their tablet comes with 1 year warranty, and you send your repairs and returns to their California office.