Ender 3 Max Universal Bed Mount with Time Lapse

My initial use for this design was to monitor my prints remotely. I later implemented the time lapse setup using the mount for the BLTouch, and the X axis tensioner.

The Universal Mount is attached to the bed carriage with four of the six bolts that hold the wheels on it. That's right, you pretty much need to rebuild your Y gantry for this. (Easy peasy.)

Parts you'll need:

Mounting Arm
(4x) 5x?? Button Cap Screw (User preference)
(4x) 5x35 Button Cap Screw
(4x) 5x16 Button Cap Screw
(4x) 5mm Nut
(6x) 5mm Flat Washer

Shutter Button
(2x) 3x12 Button Cap Screw
(2x) 4x12 Button Cap Screw
(1x) iPhone wired earbuds (Lightning or stereo)

You'll need four 5x35mm screws to mount the arm, as the 5x30mm screws already in place are too short. You must remove your print bed, and the front four wheels of the carriage. I was able to do this without removing the rear two wheels. Install the mounting arm, using the existing lock nuts. this is where you will need two washers, as only the eccentric nut side had washers on mine. Once attached, re-install the bed. You'll need to adjust your eccentric nuts for a smooth ride.

Now, for the shutter button.

Use the two 3x12mm button cap screws to attach the button pusher to the BLTouch mount. The 4x12mm screws are to replace the screws on the tensioner, which are also too short.
If you haven't already, check out my tensioner shim. it keeps the belt from rubbing on the extrusion if you're having issues.

Now you're all set, once you install the button cradle. This part can be tricky.

To install the button cradle, your printer should be on. Loosen the X axis tensioner. Remove the screws, and install the button cradle with the two 4x12mm button cap screws. Tighten only finger tight, and lean the button cradle all the way to the right. now, tension the belt. Here's the tricky part. with tension on the belt, Home the printer. Then, still holding tension, use the motion menu to move your print head to its maximum. Now, still holding tension, lean the button cradle slowly until the button pusher contacts and pushes the button. Tighten. You're done!

You may want to test the button pushing action with a very small print at first, so you can fine tune it to your preference.

The button pushing action relies on two things. (You'll have to modify your firmware.)

1. The NOZZLE_PARK_FEATURE in Marlin.
   (I have my X and Y coordinates set at X_MIN_POS +299.99 and Y_MIN_POS +299.99 because apparently 300 is out of bounds and the firmware won't compile.) I set my feedrate for XY to 120, and my z-hop to 0.3mm. G27 is the park command.

2. Cura's Post Processing
   There is a time lapse option in the post processing scripts menu of Cura. It allows you to use a custom Gcode to snap a pic. Select Time Lapse, and enter the following:

Trigger camera command: G27
Pause Length: 300ms
Park Print Head: NO
Retraction Distance: Mine is 6. Whole numbers only.
Z-Hop: 0.0 (G27 does z-hop.)

Be sure to check out my other Ender 3 Max mods as well!

The Button Pusher and Button Cradle should be printed solid. The earbud button can be glued to the cradle as pictured, and the earbud parts after the button can be cut off. I used sticky tak to install mine, so it's removable.

The Mount should be printed in the orientation given, with supports. it does not need to be solid, but should have a few top/bottom layers for strength and rigidity. If you choose the CUBEᴰ Mount, print the letters first, centered on the bed. Remove the circle before printing the mount right on top of the letters, also centered. The letters are .36mm. I used a 0.2 initial layer height and 0.16 layer height.

The Spine and Spine Clamp do not need to be solid but should be printed in the same manner as the Mount.