This may be the most compact way to mount a camera to the bed of an i3-style printer without having it collide with any part of the printer, and without requiring a large amount of space in front of the printer either. I designed it to fit inside the 25 mm (1 inch) of free space that I had between the door of my enclosure and the front of the i3's bed when it is pulled fully forward.

Watch an example time lapse here.

The camera base attaches to one of the front bed mounting holes on the Y carriage, which is available because I have converted to 3-point bed levelling. If you're waiting for a sign before converting, then maybe this is it! The mount is stable as-is, but would be even more stable if it was attached to a rigid third-party Y carriage (preferably one that has a proper 3-point levelling hole halfway down the bed).

The camera is pointed right at the center of the build plate, and held rigid so that your time lapses come out nice. The camera holder can optionally accept a wide-angle smartphone lens, but I prefer not to use one because it reduces the quality of the video, which is already not great to begin with. It is a good idea to own a lens anyway in case you want to record very large or tall objects.

Parts list

1 × Camera base.stl
1 × Camera post.stl
1 × (optional) Camera back.stl

1 × Raspberry Pi camera module
1 × (optional) longer camera module ribbon cable
1 × (optional) smartphone wide-angle lens. Check the screenshot above, it's the kind that snaps onto a collar, not the kind that screws into a holder. If you want to use the threaded kind, you will need to make the hole a big larger.

2 × 2.0–2.5 mm screws (steal them from a broken toy, they're usually holding the PCBs down). Or use some blu-tack maybe.
1 × M3 10 mm screws.
1 × M3 washer (buy it or print it; I buy steel ones so that they distribute loads properly)
1 × M3 wingnut (preferable), or some other nut or thumbscrew.

Assembly

1. Screw Camera base onto the Y carriage (not the heated bed) using the M3 screw, washer, and wingnut. A 90° guideline on the part helps you square it with the corner of the carriage.
2. Attach the camera module to the back of the Camera post with the screws. Install the ribbon cable.
3. Slide Camera back onto the post to cover the exposed circuitry of the camera module.
4. Push the post into the rectangular hole on the base until the shoulders are flush with the base.
5. If you want, push the wide-angle lens into the front of the camera post.

No

No

0.2 mm

PLA is fine since the part is not exposed to the heated bed.