Step 1: You need:
or search for "bluetooth module" on ebay
I've bought mine for $8.20 on dealextreme.
2. An Android device with bluetooth.
3. An Arduino board.
4. Some sensor or potentiometer to read values from.
Step 2: Setup the Arduino hardware
Device name: linvor
Baud rate: 9600
You can leave the settings as they are or change them with a serial adapter.
For more info see: http://wiki.openpilot.org/display/Doc/Serial+Bluetooth+Telemetry
Connect the bluetooth module to your Arduino.
BT module Rx-> Arduino Tx
BT module Tx-> Arduino Rx
VCC to 5v
GND to GND
Connect a sensor or potentiometer to analog pin A0.
Upload this sketch to your Arduino: http://pastebin.com/raw.php?i=xmyr840j
The onboard LED at D13 is toggled everytime a sensor value is requested from the Arduino.
Step 3: Setup the Android device
(This instructable is based on SL4A r4)
Copy the code from http://pastebin.com/raw.php?i=FVxKzf1g
and name it androino.html
Copy the code from http://pastebin.com/raw.php?i=XEmEsATU
and name it androino.py
Change the BT_DEVICE_ID in androino.py to the address of your BT module.
If set to None, Android will ask you at program start which bluetooth device to use.
Upload both files to the /sdcard/sl4a/scripts/ directory on your phone.
Step 4: Have fun
Start SL4A on your Android device.
Select androino.py and then the gear symbol to start the application.
The SMD LED on your BT module should stop blinking at this point.
A WebView is started and when you click on the button, the sensor value gets read and displayed.
It's really that easy :)
SL4E API reference:
I've added this script which simply dumps anything that is send via serial out from your arduino.
Select dump.py and then the console icon in SL4A to start.