Automation¶

December 3, 2025
in Automation, Blog, English
4 min read

A gripper tool for OLA & Jubilee - Part 2

This is a follow-up post to A gripper tool for OLA & Jubilee - Part 1.

Background and requirements are listed there.

homing

Tracker: https://gitlab.com/groups/open-la/-/epics/20

Homing Implementation

The wripper sits on a freely-rotating wrist, which makes wiring sensors on the tool-side complicated.

To get around this, the homing sequence proceeds in two ordered steps:

Home the wrist axis.
Align the gripping axis to the second endstop.
Home the gripper.

The most reasonable endstop options, given what i had around, were either optical or magnetic. I went with magnets because they are far more forgiving than opto-endstops in terms of alignment.

I used electromechanical Reed switches, soldered to Makerbot-style endstop boards, each one fixed to the "stator" part of the gripper.

Control

This time I just stuck the control board onto the tool, and routed only 24V and USB to it.

I really didn't want to do any more cable management. Reducing the cable count to just 3 is a real achievement.

Behind this is a firmware capable of syncronizing motion between multiple control boards. At the time of writing, I used my klipper for CNC fork.

With it I get all of the klipper goodies, and two important bits:

Kinematics for an additional axis set; A for gripping and B for turning in this case.
Homing through generalized probing (i.e. G38 commands) and basic macros.

Klipper is slowly working towards its own multi-axis features, so hopefully I won't have to maintain the fork for too long.

If you know about other firmware projects that might replace Klipper, please let me know. There is now Prunt, but it's not what I am looking for.

Proof of concept

Here is a video of it homing clumsily on a pair of stepper motors: https://www.youtube.com/watch?v=3veRTsW12Zw

Up next

Get involved. Introduce yourself and browse to the OLA tools forum.

Get in touch, join the chat! https://discord.gg/GmCeXTHpM4

A roadmap:

Replacing the servos with NEMA8 motors.
Print a Jubilee-style tool mount.
Add endstops, probably optical, probably coupled to each other (or with just one).
Review or redesign the mechanics to fox the jankiness in the motion.
Figure out kinematics for rotation & gripping.
Have a little fin with it.
Integrate to the OLA lab automation stack as a new tool: https://gitlab.com/open-la

There will be a "Part 3", no ETAs though. :)

November 17, 2025
in Automation, Blog, English
4 min read

A gripper tool for OLA & Jubilee - Part 1

After a couple years, this project has finally received my attention.

alt text

Tracker: https://gitlab.com/groups/open-la/-/epics/20

Background

I want a gripper tool for this lab robot: https://docs.openlabautomata.xyz/

Notable previous works include:

BioPick by dr3y at GitHub.
Also the awsome SO-ARM100 by TheRobotStudio.
Source Robotics' pricey gripper tool for the Parole.
Several others at the GOSH forum.

Some requirements

Gripping action: for tiny (e.g. seeds) and medium-sized stuff (well-plates and petri dishes). Nothing too heavy.
Wrist action: with unbound spinning angle.
Affordable, ubiquitous components.
Mostly 3D-printed parts.
Upgradable.
Open-source hardware.
Synchronizable motion.

Nice to haves:

Eccentric grip.

Implementation

Hollow-shaft concept: a pair of concentric shafts transmit force to different parts of the actuator.
- The broader shaft (8 mm) rotates the wrist.
- The narrow shaft (5 mm) passes through it, and actuates the gripper claws.
- Because of this arrangement, the wrist is coupled to the grip action. Both motors will need to turn in sync for the claws to rotate and hold a certain grip.