Minimal Raspberry Pi setup for MQTT on Puck.js

Is there a requirement to install everything in the "Installation of EspruinoHub and Web IDE" section from the EspruinoHub github page?

Yes, apart from the git clone bits commented as 'optional'.

So all you need then is to use something like NRF.setAdvertising({0xFFFF:[buttonPresses]}); on the Puck - and you're then looking to see when packets on /ble/advertise/DEVICE/ffff change.

To toggle the LEDs, write "\x10E.getTemperature()\n" to /ble/write/DEVICE/nus/nus_tx