I've not used hall effect sensors before so am I correct in saying that they are essentially a digital signal that uses the frequency to assimilate the value? If that is the case, is there a way that I can get the GPIO Node_Red to trigger interrupts so I can measure this?
Broadly speaking, and for real world operation, I would utilise either a esp8266 or arduino microcontroller at the sensor location. Then get that to transmit data back to the RPi which would be running NR and other stuff.
The RPi (and NR) end is relatively easy. The micro at the sensor end needs to have some way to transmit data back (esp has built in wifi, arduino would need a wireless transceiver like the NRF24L01).
Another approach would be to use a PiZeroW at the sensor end. But personally, I think the RPi is not the right device for attaching one or two sensors (except perhaps for education purposes).
If you are undertaking an educational exercise/project then what does the sensor spec sheet say about how you would interface it to a microcontroller?
Doing a little more online reading the consensus aligns with your suggestion.
I have a Wuzzah32 sitting in the packet on my bench so I might just use this device.
Slightly annoying I need to add another device to achieve what I need but understand the advantages.
Yes, there is so much you can do with a "central" RPi. Run NR, Grafana, InfluxDB, Mosquitto (mqtt), Apache ... the list is endless. But on that device you don't really want to attach much in the way of hardware.
