So I got really excited by the auto-leveling feature just pushed to the Marlin feature, so I am putting together something that will attach to my printer and allow me to drop a switch down using a servo so I can auto level my bed. As you can see there are some problems with the first version I printed. Once I have a working prototype I’ll throw it up on #youmagine and #thingiverse. Fully parametric OpenSCAD design of course.
And for anyone reading. You MUST jumper the vcc and 5v pins on the ramps board. (And solder in pins for it and for servo if, like me, you didn’t bother with it at first ;-)) That was my last two hours of frustration
You probably want to use better servos. These tiny blue ones are weak and not at all accurate. It won’t give you the sane distance twice. Have a look at the towerpro s3003. They are much better and not that expensive.
I was thinking the same thing @Mano_Biletsky_Open_M , in fact driving any servo directly from the arduino tends to be “twitchy”, so I was surprised that it works well enough for this application.
That said, it appears to work, so I’m starting with a small servo too (figure the less moving mass the better) and if it’s not enough I have some nicer full-size ones to try.
…of course I have to get my wiring straightened out first, looks like I soldered in the only header I have in-stock to the wrong servo port.
@Aaron_Kartash Yes it does matter! If the servo is moving the switch down. But the next time it stopt a bit early and the switch is positioned higher. Thus, the nozzle will push through your bed, breaking the glass. The whole point of this system is accuracy. You’ll loose that with bad servos.
Another issue I “discovered” is that the probe MUST be away from you’re homing xy position. Designed a a bracket that did the opposite. It is a bug I think, as it could just as we’ll take into consideration the offset before homing Z. To mitigate I will move my endstops to the other ends.
@ThantiK that was immediately apparent after I actually printed it. I am very tempted to have the end stop actually extend back towards where the hotend is so it is very close for better results.
@Jelle_Boomstra I’m just trying to support Ultimaker’s efforts.
@Mano_Biletsky_Open_M you are correct the servo is rather small. I thought I’d see how well it worked, I have a few larger ones to try if needed but was going for smaller mass first.
The servo “issue” largely can be solved by adding a bump-stop and programming the servo to go slightly past it. Servo strength/size doesn’t matter, as long as it puts the microswitch in the same position every time, and that position isn’t based on rotation of the servo, it’s based on the relation to the shaft that it pivots on, which won’t change.
