I want to hack an air purifier with this touch buttons to build an smart one.
How can I manage to control this buttons with an ESP8266 for example
thanks
Without a schematic the simplest way would be with relays. They can parallel the contacts on the unit. If by chance they are normally closed then use the normally closed relay contact in series.
thx
what kind of relay should I use?
They make relay boards for the Arduino that have the coil driver etc already built in so the Arduino can drive them directly. Some have LEDs, some are Active High, Active Low, or both. There is a variety of voltages available, the easiest sounding solution is to get a 5 volt one and use the Arduino 5V power, This is the absolute worst thing you can do, the Arduino is not a power supply. You need to determine how you are going to power this project, that will make picking the correct relay straight forward.