ELK Grafana show online devices

Hi to all,
I search online and in the community forum but i didn’t find a solution for my needs.
I have about 30 devices that use cellular network. I’m using filebeat to send logs to ELK stack on a virtual machine and Grafana for the dashboards.
I need a panel (like Status Panel plugin) or something else to show the status of my devices (online/offline).
I want to achieve this only using last log received timestamp.
I tried using a table where in a cell I get the timestamp with From Now representation but it’s not possible to make threshold (green/yellow/red) on that.
Is there another way to achive this?

Thank you

If the device use IP, you can use heartbeat to check on or of, because in heartbeat there are fields for summary.up and summary.down, also have rtt for icmp.
Then you can visualized it when the devices down or up, also count the down and up.
I think log can not get the state of online/offline

Fadjar Tandabawana