This tutorial is intended to show the minimum steps to get a Bluetooth 4.0 CC2540 Module to connect to an Android Smartphone or tablet.
Step 1: Buy Arudino Nano on Ebay for $3
Step 2: Buy a Bluetooth BLE "SMART" Serial Uart on Ebay for $3.46
Step 3: Connect the Nano and the Bluetooth Serial Module
Step 4: Select Board Type to Be a Nano and Then Upload ASCII Example Code to Your Arduino
Step 5: Download HM BLE Terminal APP From Google Play Store
Step 6: Launch the BLE Terminal App
Step 7: Open the Menu Button Then Hit Connect So You Can Scan for New Devices
Step 8: Connect to the Serial Module
The android device will then search for available devices.
It should find a BT05. Select this device to connect to.
Step 9: Hit the Reset Button on the Arduino and You Should See the Communication Happen
From here you can write your own code. A Serial.print(" your text or data here "); is all that is needed.
Note you need to hit the clear screen button on the android app to see new data from your device.
I hope it works for you.