MQTT data - how do get this into Signalk/influxdb?

[Sea-and-Sea]

On one side of the boat i have a Victron 712 which feeds data via usb to a Pi zero which in turn feeds into an MQTT broker.  i need to get this data from MQTT into SignalK to be sent on to InfluxDB

The bit i'm stuck with is how to get the data out of the MQTT Broker.

I can see there are 4 MQTT related SignalK apps, but they all seem to go from sk to mqtt and not the other way.

What am i missing?
Colin

[jim321]

i used node red.
mqtt sends info on topic ,,data allways sends it, you have to subscribe to topic to get the info