Setup and Calibration failures

Hello all.
This started with groundcontrol on an old laptop pre-covid, but we never quite got calibrated.
But covid’s endemic now so we started to get back into it. Getting caught up in the reading [here], there were a lot of new updates, so we decided to restart from the start with the new knowledge that has accumulated over the last 3ish years. We had been using an old laptop and groundcontrol, but when we read the updates we switched to a raspberry pi and webcontrol fresh without importing the groundcontrol.ini file.

Alas, we now cannot seem to get to the “triangular calibration” test.
When we run the “Test Motors/Encoders”, left and right work properly, and Z tries to work but will no longer move the router up and down. It does move the Z connector to the router, but it can’t overcome the static friction and just wiggles in it’s slot back and forth.

Then I do the “Set sprockets and chains”, and everything again seems to work well. I did do the whole thing from scratch to create the marks on the chain, but now I just reset the chain to those marks on the motors and hit “set zero”. All of which seems to work very well.

But, when I try and manually drive Z for a longer run to see if it can move the router if given more of a chance, or in fact when I try to interact with the device in any way other than previously mentioned, all that happens is that the right motor whines, the sled drops, and then the entire system freezes up.

We have tried:
-Wiping eeprom settings
-reflashing fresh 1.26 firmware
-reburning raspberry pi SD
-trying new SD card
-redownloading the program from both github and eastbaysource

Including all but new SD card at once now for 3 times in a row, the only difference being changing from github to eastbaysource.
One thing we did notice, the eastbaysource installation was noticeably faster in the “test motors and encoders” and the other things we tried, MUCH smoother even though the software claims to be the exact same file.

But other than that, when we try and do any high level interaction with the machine, including triangular calibration, all that happens is the right motor whines and drops the sled a bit, and then everything wedges and “stop” flashes, with no error messages shown.

We’re at a serious loss here. We really want this to work but have no idea what we’re possibly doing wrong. I’ve got the dimensions memorized I’ve put them into the quick calibration so much.

Help me Obi Wan Kenobi.
You’re our only hope! :wink:


This sounds like a sled not keeping up error. What shield do you have (should have a printed 1.xx number on it somewhere.

The early motor control boards (shields) had 2 chips and the left motor was on one and the right and z were on the other. that is a potential point of failure if that chip fries and will affect z and the right.

A couple things to think through / work through:

  1. is the right motor jammed inside the gearbox? If it were, then it would try, then overheat the controller and stall and not do anything.

  2. is the right motor plug not fully seated… not getting encoder feedback when it moves?

  3. is the sled not keeping up error stopping you? if so, change the setting from 2 mm to 20 mm. This will also show up if you forget to connect the shield power to 12 V (upper board)

  4. is your motor driver chip on the shield fried? check back if 1-3 are not the issues and we can work through how to verify that.

  5. is the z axis enabled in the settings?

  6. is the z axis pitch correct?

  7. is the board getting hot to the touch, are the heatsinks in place? do you ever get disjointed movement when one motor stops and the other goes creating a zigzag instead of a straight line - typically horizontal close to the top of the work space?

With the RPI, you shouldn’t need to reflash it more that once unless you are testing something and do it wrong. I think it is safe to say the issue could be software configuration or hardware connections… possibly a motor or a chip, but less likely the latter.

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Haven’t been back to work to answer all the questions, but from memory:

  1. It works just fine when I drive it directly, no whining or catching and actually runs really smooth, same as the left.

  2. We did at one point have this problem I remember now, but changing it to 20mm didn’t change anything.

  3. Yes.

  4. We’ve left it default and haven’t touched it that I remember, but I can double-check.

  5. I did feel the motors at one point and nothing felt hot, I didn’t think to test the heat of the shields.

Re: the pi: We did find a huge difference in functionality with the eastbaysource raspberry pi img immediately, it was shocking.

Thanks for the tips, I should be at the shop soon to test and get more info!

This is embarrassing.

I was confusing “Define Zero” under “Set Sprockets And Chains” with “Reset Chains”, specifically “I have reset … to the mark”.

So I was accidentally using “Define Zero” when I meant “I have reset…”, then trying to move, and the machine thought both chains were at 0 length and, well did whatever.

Once I figured that out today, we are now well on our way. Not quite a circular sled but very very close! (approx 2-3mm difference long side to short side) We’ve only done the calibration loop once, so we’ll swap with the better-than-square sled and try another round!

Thanks @Orob.

In tech support we call these a “pebcak”
Problem Exists Between Chair And Keyboard

I’ve heard of it as a picnic → problem in chair, not in computer…

Great to hear you got it sorted out! Thanks for posting back

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same here!! and is something I use almost daily in my job!!

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problem exists between keyboard and chair

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