So whenever my phone gets close, and it connects to the Hc-05, the Arduino changes a variable? I want to avoid the use of apps, where the user has to do anything after first time connecting. The project is an automatic door opener, wherein the user for whatever reason can't use their hands, like if they have groceries in their hands.
Thank you for your time
The HC-05 can be configured to do what you are after.
Search for "POLAR" in the AT set documentation.
AT+POLAR=0,1
should be what you need as per their examples. Hook up PI09 to your arduino and wait for it to go HIGH. You may even want to wake up your arduino with an hardware interrupt using that signal.
Depending on your package, this may require soldering to the HC-05 module. The datasheet features a pinout in that case. Be sure to checkout the manual of your breakout board first.
