It's a possibilty, but I think by the time you have added the multiplexer and all the mosfets required it would be almost as complicated as using separate stepper drivers. Stepper drivers are basically a bunch of mosfets in a single package anyway.
I hear more rumours of 4 way hotends, so it's time to revise the extruder expansion board again.
I need to rework the 6 channel version (EXT6) with improvements I have picked up from RAMPS-FD. I also haven't got round to writing any firmware to support it.
While I wait to do that, I decided to revisit EXT4. That had the advantage of not needing any special firmware support, and should be plug and play. I reworked the layout and I think came up with a much better design.
So there will be two versions, EXT4, a simple extension, and EXT6, a more advanced version to support up to 8 channels.
This is EXT4 as it currently looks:
[attachment 24176 EXT4.png]
The thermistor inputs have their own zone in the corner with a separate Reference voltage and ground, and the stepper drivers and heater mosfets are also separated in two zones, although they share a common ground.
I hear more rumours of 4 way hotends, so it's time to revise the extruder expansion board again.
I need to rework the 6 channel version (EXT6) with improvements I have picked up from RAMPS-FD. I also haven't got round to writing any firmware to support it.
While I wait to do that, I decided to revisit EXT4. That had the advantage of not needing any special firmware support, and should be plug and play. I reworked the layout and I think came up with a much better design.
So there will be two versions, EXT4, a simple extension, and EXT6, a more advanced version to support up to 8 channels.
This is EXT4 as it currently looks:
[attachment 24176 EXT4.png]
The thermistor inputs have their own zone in the corner with a separate Reference voltage and ground, and the stepper drivers and heater mosfets are also separated in two zones, although they share a common ground.