Keyring magnet

A simple keyring thing with an embedded magnet. I use a pair of them to keep my car keys and house keys together. This lets me keep the house keys in my pocket so I don't have them bashing against my knee when I drive.

I used these 4 x 8mm magnets

#Printing notes
0.1mm layers look nice, but 0.15 worked fine too.

You will need to add a pause to insert the magnets. I did it at the 4.5mm layer change and inserted this GCode:

; Pause to insert magnets
G1 X10.000 Y200.000 E0  ; parking position
; Move print head up proportionally of print height to max  
{if layer_z < max_print_height}G1 Z{z_offset+min((layer_z/max_print_height)*(max_print_height-100)+100, max_print_height)}{endif}
M400                    ; Finish moves
M300 S2500 P1000        ; beep
M0 Add Inserts          ; User stop with message
M105                    ; return to current temp

When you insert the magnets you need to ensure that half of them are north-up and the other half are north-down otherwise they will repel rather than attract each other! It's a bit fiddly and the magnets want to grab each other so you need to take care. Once they're in the pockets it's not a problem as they snap to the steel bed on the Prusa. I'm guessing printers with glass beds might be more trouble so your mileage might vary.