it’s been pretty reliable. the trigger i’m using is not that it has joined the wifi network, but that it has ARPed for something. in fact it’s less than that, the script just looks for a packet from the right mac address, no matter what it is (but i’m pretty sure the first thing it does is an ARP)
the line in question is:
tcpdump -c 1 ether src host [macaddr] >& /dev/null
which blocks until a single packet with the mac address of the dash button is seen. the following script just then goes off and sends a push notification (via Pushover) and starts a video feed for 30 seconds on the computer running the script.)
the nice thing is that this can run on any computer… and in fact, i have another computer running homebridge with the videodoorbell plugin which basically does the same thing. over there i have another plugin for dash buttons which starts the process, which i believe also looks for an L2 packet from the button. so now i’m firmly in belt and suspenders territory - i get notifications from Pushover, and also homekit notifications when someone pushes the button.
i guess one problem is there’s no feedback for the user - the button does not make any noise and the only indication something happened is that the LED flashes. but so far no one has mashed the hell out of the button.
i just realized that since they have discontinued these, that there may be no way to configure one in the future if they remove the configuration stuff from the amazon app. it might be time to buy one of their IoT buttons as a backup.
