Is it possible to use bluetooth module hc-06 in Master mode
The HC-05 and HC-06 are identical, except the firmware they get shipped with. For whatever reason, the HC-06 has a simpler, slave only firmware. The HC-05 has a much more completed command set. There was some attempts to reflash or change the firmwares on these but the projects were a bit obscure. It's just cheaper and faster to get the HC-05 or a newer master capable bluetooth module.