I don't think Lansweeper is the best, or even a "good enough" solution for that.
Lansweeper checks IP's every 24-hours, and you want something that checks every minute or at most every 5 minutes.
On the Opensource field, you can check things like Nagios, Zabbix, Zenoss, those are the more commom used ones for that purpose. They can a bit tricky to install/maintain, if you aren't a Linux guy...
And them there is a LARGE number of commercial solutions for that, check these lists:
https://en.wikipedia.org/wiki/Comparison_of_network_monitoring_systems
https://www.slac.stanford.edu/xorg/nmtf/nmtf-tools.html