I'm running Raspberry Pi (3B+) 9 (stretch) Wlan0 connected to WAN with network info stored in wpa_supplicant.conf.
I recently purchased an Wifi dongle in order to create a wireless access point from which an Arduino can connect and transmit data (temperature readings) in to the raspberry with a lightweight webserver. This secondary network does not need to be bridged with wlan0 (WAN), since its purpose is to only retrieve data from arduino.
I'm able to find several questions which addresses the issue of using the second wlan1 as a repeater or bridge to wlan0, but not as stand alone local network. Preferably i also want the network SSID to be hidden.
Any good solutions ?
systemd-networkd
you could also follow this tutorial.