Doug Joseph (Design8Studio) Full-Sheet LowRider 2 "Build on a Budget"

LowRider CNC Your Builds
11

OK, so a quick SENSORLESS HOMING firmware update success story.

First, my LowRider V2’s mainboard is SKR Pro 1.2 with five (5) TMC2209 drivers (this all came in my kit ordered from V1).

I have never installed any endstops, and had been seriously considering dual endstops. I’m not sure why I had never considered sensorless homing. I guess I did not even realize it was an option with my 2209 drivers.

I happened to stumble onto a YouTube video by @KCGreg about (among other things) enabling sensorless homing on his LowRider v2, and I then began reading up on both his notes here on the forum (link below), as well as the various comments/replies to it, all taken in combination with a video on YouTube (linked below) about configuring Marlin starting from scratch — toward getting sensorless homing working on my very same board and drivers.

Notes:

I’m currently homing to Z-min instead of Z-max for two reasons.

  1. My table is large enough for the router / bit to be off the edge of any work piece (no danger of a router bit hitting anything when homing).

  2. I had long since replaced the “spiral /spring type” couplers (from the kit, for the Z-screws) with the “solid” kind of couplers instead. The “spring” type are so easy to pull apart.

I started off trying to configure a fresh download of Marlin (aka from scratch), however, after setting Extruders to 0 (a needed step) I got some compile errors related to not having the right number of axes defined, which threw me off at first. I felt overwhelmed at the time, like I could not get that sorted, so I resorted to editing a copy of the most recent Dual-Endstop firmware for the LowRider v2 from V1 Engineering. I ran into issues there, and then started editing a copy of the normal (non-dual endstop) LowRider v2 from V1 Engineering. That’s the one I was tweaking when I finally solved the above issues regarding having the right number of axes values, and got full success.

I practiced a couple of tips I have learned over time about editing firmware in VSCode:

  • Immediately compile the initial, unedited, known-good firmware just to make sure all is well.
  • Compile again after each change, so if one of a bunch of edits is going to break something, you immediately know which edit was the culprit. Although, this tip cannot always be followed, as some edits have to happen in batches.
  • Another tip, which was not really needed after I switched to editing the V1 dual firmware, is if you’re getting errors on a first compile, bear in mind some things get built out of order, and so just immediately try compiling a second and third time. If you still get errors, find the first one and fix it, as others after it are likely related to it.

BUILD SUCCESS → HOMING SUCCESS

After quite a few iterations of config tweaks (after each of which I loaded new firmware on the board), I finally got a successful one. Finally, all went without a hitch. I can tap on the Home-related choices icon, and then the HomeXY button, and the X and Y axes home exactly as expected (with anti-racking on the Y). I can then tap on the HomeZ button, and it homes as expected, in a way that corrects it being out of square.

Below is a link to a zip file of my build and configuration and the final compiled bin file:
https://design8studio.com/2022/01/17/sensorless-dual-homing-on-lowrider-v2-with-skr-pro-1-2-and-tmc2209-drivers/dual-sensorless-by-doug-joseph-based-on-v1cnc_skrpro_2209-2-0-9-2/

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