MQTT

At London Hackspace, we use the MQTT protocol to pass messages between systems.

Doorbots send /door/doorname/announcements messages
Doorbots send /door/doorname/bell messages when the doorbell button is pressed
Doorbots send /door/doorname/status messages every 30 seconds or so

acnodes send /tool/toolname/status messages every 30 seconds or so

bandwidth meter listens for /door/+/announcements, /door/+/bell messages
signs listens for /door/+/announcements, /door/+/bell messages

MQTT server is mqtt.lan.london.hackspace.org.uk, a virtual machine running on landin

if the mosquitto process is restarted, most clients should reconnect. Those that don't automatically reconnect at present include listener-ola, listener-signs, listener-bmeter, glados, listener-irc, listener-lastseen