I am building a robot car with 2 DC motors, Arduino UNO R3 and controlled with an HC-05 Bluetooth module via my Android phone. I used a perfboard as an UNO shield that will hold all the components; motor driver and female pin socket for the HC-05 Bluetooth module, along with some LEDs and resistors. However, the HC-05 module sticks out and i want to reduce its size to make the overall perfboard more compact and eventually transfer all the components to a custom PCB. What are some possible replacements that would not necessitate changes to my Arduino code or Android app code?
I've found the HC-12 which looks like it could simply be soldered onto the perfboard but it also comes with an antenna... Is that a requirement?
There is also the HM-13 and the newest HM-19.
I also found this: nRF52840 Bluetooth Low Energy Module with USB - MDBT50Q-1M from Adafruit: nRF52840 Bluetooth Low Energy Module with USB [MDBT50Q-1MV2] : ID 4078 : $12.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Can all of these work as drop-in replacements for the HC-05? Are there any others that i missed?