While you can make use of specialized system admin tools to find out which devices have been connected to a local area network in the past, it is not really something that is really something that you may want to explore if you need to run a quick check.
That's what NetworkConnectLog by Nirsoft has been created for. It is a lightweight portable networking tool that scans the local area network for you in intervals to record any device connections to its log.
To use it, download it from the Nirsoft website and unpack the archive to a directory on your Windows PC. Run the program afterwards to start the logging.
Please note that it may display an UAC prompt depending on the version of Windows that you are using. According to the program's page on the Nirsoft website, it is compatible with all versions of Windows from Windows 2000 onwards including all 32-bit and 64-bit editions that Microsoft has made available.
The program runs a first scan on start up and adds all devices that are connected at the time to the program interface.
Each device is listed with its computer and workgroup name, mac address, network adapter, event type (first scan, connected, disconnected), as well as the recorded date and time.
You can sort the table with a click on any column header, for instance by Mac address or IP address. The program continues to scan the local area network for as long as it is running. There is no stop or pause button currently, you need to exit the application to stop the scans.
A click on options > scan options or a tap on F9 displays the list of network adapters so that you can make changes here.
Instead of selecting one and using its range automatically, you can alternatively select to scan a custom IP range instead.
NetworkConnectLog ships with the usual Nirsoft traits. You can export the data to csv, xml or text files, or generate an HTML report instead.
Nirsoft's NetworkConnectLog is a handy program for users who want to either scan the network just once to get a list of devices connected to it, or who want to get a listing of connected devices over time instead. The program could use a pause or stop button though as it is not really that user friendly to close the app each time you want to pause the scanning for the time being.