Merging rasters in R - errors using mosaic function

Question

I'm trying to use the mosaic function (package: raster) in R to join two geo-tiff rasters together. Both are derived from LandSat tiles. I understand that mosaic requires

All objects must have the same origin, resolution, and coordinate reference system.

Unfortunately, the two tiles have different CRS

+proj=utm +zone=33 +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0

and

+proj=utm +zone=32 +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0 

leading to

Error in compareRaster(x, extent = FALSE, rowcol = FALSE, orig = TRUE,  : 
  different CRS

So, I converted them to the same crs by using projectRaster - I've tried reprojecting both rasters to both epsg:3857 and epsg:4326

However, having done this, in both cases when I run the mosaic function I get the error

Error in compareRaster(x, extent = FALSE, rowcol = FALSE, orig = TRUE,  : 
  different origin

How can I fix this? Is there a different crs I could use that would use the same origin for both?

Answer 1

So my workaround was to create a very large raster file (just drew it out in QGIS) that covers the entirety of the desired area, then resample using that raster for the parameters.