To identify which all devices are connected to your Router in Wireless network, we can use nmap command which internally uses ARP request/reply scan to show which all devices and their mac address and IP address are actively connected to our router.
$ sudo nmap -PR 192.168.0.1/24 -sn Starting Nmap 7.01 ( https://nmap.org ) at 2018-04-18 01:07 IST Nmap scan report for 192.168.0.1 Host is up (0.0017s latency). MAC Address: (Tp-link Technologies) Nmap scan report for 192.168.0.104 Host is up (0.0068s latency). MAC Address: (Samsung Electronics) Nmap scan report for 192.168.0.106 Host is up. Nmap done: 256 IP addresses (3 hosts up) scanned in 28.10 seconds
In our network we had 2 devices, 1 laptop and 1 Mobile connected to the router. So, nmap which was initiated from latop with IP address 192.168.0.106 shows that we are connected to router with IP address 192.168.0.1 and second device connected to this router is with IP address 192.168.0.104.
You can also check How to get all the details of a device using IP address in Linux/Ubuntu