App of the day: WiFi Watch for Android
WiFi Watch Android app will allow you to find out how many WiFi devices are connected with your home WiFi network. If you are looking for a way to find out which devices are connected to your WiFi than WiFi Watch is one of the best way to figure it out right on your Android device.
With WiFi Watch you can scan your network for all reachable devices (not only the wireless, also the wired ones), and even more, you can monitor automatically when they connect/disconnect, as the app checks automatically (only if you want, you can disable it).
You can also check out the IPs, names (hostname), MAC addresses and Manufacturers of the devices currently or recently connected (the Manufacturer is actually the one who made the network card of the device, sometimes will be the same one of the device itself, sometimes will be different), so even if they are not using the network right now, but they used it lately, you will have this info (Anyway, your router must be capable of it).