Prusa MK3 Camera Bed Mount Arm

by ironhalo Dec 26, 2017
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Works well. I think the cable holder would be better off on the side or at least on an angle - there is a risk of it getting caught to the printer frame as the Y-axis moves all the way to the front.

loose fit and the zip ties don't line up right on my mk3. one of them lines up right under the bed shim. unuseable really. even if you force the second tie down it's not tight.

Sounds like your print settings are off. It's a perfect fit when printed correctly. I would check your extrusion with an extrusion test print. Sounds like you might be under extruding.

I use this one: https://www.thingiverse.com/thing:1622868

Also, the tie alignment is by design, the bottom of the tie is under the bed shim so that the top of the tie will be hugging the shim and creating a lateral force to help keep the arm tight to the frame.

Fast edge over/under extrusion test

Why is the arm so long? I was gonna remix shorter, but maybe you had a specific reason to make it that long.

If you make it much shorter the camera can collide with the extruder motor when the bed moves to the back of the printer. I left a little margin for safety, but not much.

Ok, I’m going to try trimming off 20mm... seems like it can tolerate that much.

Did you ever finish that accessory rail design?

I finished a preliminary design of the accessory rail system, but wasn't happy with the vibration I was seeing or the amount of weight it was adding to the front of the bed. May revisit later as time permits.

Slightly off topic, but where did you get a pi zero ribbon cable long enough to mount your camera to the front of the build plate? The longest I've seen that have the smaller pi zero connector are only 300mm.

Yeah, the longest one I found was 300mm as well. So I remote mounted my Pi Zero underneath the camera, and ran extension wires from the Pi to the EINSY accessory port. Another solution is to buy a longer (wide version) Pi cable, and a cable joiner to extend the wide end of the Pi zero cable.

The RIGHT side option is a no go on the MK3. The left and right sides for the frame are not the same distance from the smooth rod connections. Plenty of clearance on the left. Right side is much closer for me. Sadly hour and a half of wasted time.

Sorry about that, never tested the right side myself. Surprised no one else flagged this after so many downloads. I've uploaded a new file with more clearance. Although you can probably take the one you already printed and just snip the corner off with some snips. It only needed a few mm of plastic removed to clear the rail.

Also if anyone else is interested I made a fusion 360 file for the left arm. I believe this to be on the money but want to be clear that it is untested. Just change the height dimension for the sketch that defines the vertical cylinder and the ball should reposition itself accordingly.

I'm completely terrible at Fusion. With the R3 components, the front fan now gets in the way of the camera mount during the auto homing feature. Is there a way to extend the arm so that the fan doesn't affect the mount?

The 175mm tall camera mount seems to work great. Just needs lighting and some focusing now. https://youtu.be/jRKHEZUBRU4

Thanks a lot for addressing this so quickly! I did get the left one working properly. I plan on remixing to get some more height. If you're interested I did make a timelapse of printing the left mount and of printing a calibration cube using the correct camera mount. https://www.youtube.com/watch?v=HffqZvrXMBc https://www.youtube.com/watch?v=KZoSbjqBWLI

Hi. I really liked the idea of cable going throw the holder (even if it is not shown on pictures). But it turned out than you cannot use this very well because you the cable is kind of twisted this way if you turn camera and you cannot lead the cable together with LCD cables.
Also the mount does not hold very well on the frame even with zipties (but could be affected by print tolerances). However, I am not a big fan of ball connection anyway so I made a bit more robust version: https://www.thingiverse.com/thing:2736439.

Prusa i3 MK2/MK3 Raspberry Camera Mount
by jgeyer

Nice. I like your improvements, especially the connection method to the bed rail. And I agree, there is nothing good about the ribbon cable, it's a disaster to try to gracefully route it anywhere. This setup was really just a quick temporary solution, and I'll be ditching it for a completely new design soon. I plan to convert the ribbon cable to a round shielded cable that can be easily routed and hidden, and ditch the single mount point arm for an adjustable accessory rail. I'll post something once I have a working design.

Do you mind sharing the cad file? I've a need to modify it to fit a different camera and the cad file would save some work.

Sorry, it's not a proper CAD file. It's just an STL mesh I imported into Fusion 360 and did some quick patchwork on. Here is a .DWG file, but it won't be all that helpful.

Ah, I see what you mean. Looks like I will be designing a camera mount for the ball instead.

Hi it's TheSquall from the Prusa forums. Any way to have an additional one of these for a higher ball? I want to be able to look down a bit more at the print instead of look at it from the side. Maybe like 4-6 inches high? I'm kinda guessing on this, since I obviously don't have anything to try it with, and I'm just really bad at CAD.

Yeah, I was considering making that adjustment for myself as well. Although I'll probably only make mine 2-3 inches tall.

Here is a version that has a height of about 4 inches. I haven't printed it myself, but you can give it a shot. I'm editing an imported mesh rather than designing from scratch, so no guarantees it will behave as desired.

Replied in a separate comment, but I'll reply here. Do you still have the file for this? I'm not too great at Fusion, but the middle portion (where it goes from the mount to the frame to the vertical part that connects to the camera) needs to be extended a bit if a user has the R3 upgrade on the printer, which causes the front print fan to extend out past the extruder motor. Do you think you can help out? :)

Quick glance with a very scientific instrument (a ruler and my eyes) says that hte fan is extended about 3/4 of an inch, so we would need to make the arm that much longer. Thanks

I've updated the design with 20mm of extra length on the arm, but I'll need someone to test it for me to make sure that's enough length. I'm not using a mounted camera anymore. Thanks.

I updated the file using TinkerCAD (thank goodness for YouTube assistance on this). I increased the length by 22mm and the height by 32 mm, so the overall dimensions are 123.12x28.62x149.67 (original was 101.12x28.62x117.67).

I haven't had time to print yet, since my printer is waiting on a new home. I'm posting this just in case someone else wants to try them.

Printed it and it came out well. As I was re-hooking everything up, my camera cable unplugged from the Pi0, so I was unable to check to see how good the height was.

Only complaint is that with it being on the left side of the bed, it makes it difficult to be able to reach the SD card if needed. My last request would be for it to be able to be mounted on the right side of the bed :)

Looks like it should be ok in Slic3r. I need to finish printing my castle (stress test of the printer) and I'll run this after.