I'd claim that this is the best and easiest Hemera Upgrade for your i3 MK3s out there if you're willing to leave the filament sensor away.
Instructions
Instructions with photos: https://imgur.com/a/45Vc4Xh
About
This mod changes the PINDA position to X +30.6 and Y +11.6.
I tested Z- and first layer calibration with the stock firmare. Mesh levelling might be a tiny bit off obviously, but doesn't really impact print quality. A modified Firmware with changed probe position and mesh coordinates ready to download over on thingiverse (https://www.thingiverse.com/thing:4510337).
My previous version requred to replace the Z axis parts on the right, which required quite some effort to do. This mod here optimised the extruder placement to make use of the full printing space, without much hassle.
If you want to add your filament sensor back, there is a STEP file for modifying. I didn't upload my fusion project because I referenced some parts/files that I don't know the licencing of (and it got a bit messy).
Compiled firmware included
Version 3.9.0 for Prusa MK3s
Changes done:
#define MESH_MIN_X 31
#define MESH_MAX_X 228
#define MESH_MIN_Y 12
#define MESH_MAX_Y 210
and
#define X_PROBE_OFFSET_FROM_EXTRUDER 30.6 // Z probe to nozzle X offset: -left +right
#define Y_PROBE_OFFSET_FROM_EXTRUDER 11.6 // Z probe to nozzle Y offset: -front +behind
to this configuration:
(here you can see the default values)
I added the modified and compiled firmware as .hex file, since i ran into so much trouble compiling it. Use the Firmware Updater in PrusaSlicer or in Octoprint to flash it.
The firmware is under GNU GPL licence. Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm.
https://prusa3d.github.io/Prusa-Firmware-Doc/
https://github.com/prusa3d/Prusa-Firmware
Supports: Yes
Resolution: 0.2
Infill: 30
Filament: PETG
Notes:
Use support in the regions mentioned in the picture above.
The author marked this model as their own original creation. Imported from Thingiverse.