DigitalWrite Cannot Power HC-06 Bluetooth
A digital IO pin is only capable of powering an LED or an incredibly low powered device. It is not suitable for powering meaty RF modules.

Instead you need to control the power to your module using a P-channel MOSFET as a High-Side switch.

For instance, assuming a 5V module with built in 3.3V LDO:







simulate this circuit &ndash; Schematic created using CircuitLab

Note that /RFEN is active low - set the pin OUTPUT and LOW to turn the module on. M1 should have a threshold of no lower than -4V, better -2V or higher.

Also be sure to set RX and TX to be INPUT when you power down the module or back-powering through the TX/RX pins may occur.

R2/R3 is a simple logic level shifter for the 3.3V logic signal the RX pin expects.