The Button is supposed to be for starting the "Google Voice Search". It is easier to push a button while driving than unlock my phone and start Voice Search. Connecting the two devices could be achieved by setting up the RPi as accesspoint. I already use NFC to activate the wifi on my phone with pro...

Ok, here is my scenario: I want to build the RPi in my car. Once I get in the car my phone should connect to the RPi (preferably by wifi). When I press a button I want to start the "Google Voice Search" on my phone, to interact with my phone.

Thanks for your reply! Sounds great! I thought about writing my own app. But if it is possible to do that with tasker it would be perfect!! Could you please explain how the communication between Tasker and MQTT works? Do you have a tutorial?

Hello! Is it possible to start an App on my Android cellphone (e.g. Google Voice Search) by pressing a button connected to my RaspberryPi ? My cellphone is connected by wifi with my RaspberryPi.