No need for Octoprint - a Duet controller has its own and very good web interface right out of the box: Duet Web Control Manual | Duet3D Documentation
The main work with swapping was four things:
- metal work: getting a hole for the Wifi antenna and the cooling fan into the side of the printer. That one frightened me the most, but it was easier than expected.
- soldering adapter cables for all those custom J1 connectors and to figure out where some additional capacitors were due was what took me the longest apart from getting the config and calibration macros done
- the wiring of the cooling fan on the J1 is “common ground, PWM positive” - which is incompatible to pretty much anything else. Changing this requires unsoldering the fan connector on the hotend PCBs that are behind the extruder steppers, isolating one pin and reconnecting it to a 24V connector plate that is close to the connector
- and lastly, I went for the most complicated possible way to get the analogue (those things spit out a sawtooth voltage each 360°!) filament sensors of the J1 to run with the Duet and completely rebuilt those. The easier way would be to read them out by an Arduino or such and send the digital pulses to the Duet… or to switch to other filament sensors.
If you want, search www.mechanotronikum.de for the “J1” tag for a more detailed explanation. If you see an error message, write me a PM that I can allow acces for your country (currently, I only allow access for european countries to minimise spam).
Alternatively, someone here mentioned he got a Klipper board into his J1.