Work in progress · not for sale

A tool changer for the SO-101 arm

A 3D-printed twist-lock mount so one robot arm can pick up and put down its own tools.

Status: a person has flown the arm through a few successful catches. It can't swap tools by itself yet.

Get an email when something real happens with it.

A short welcome, then build updates on the SO-101 tool changer when something real happens (about two emails a month at most). If I ever release files, a kit or a price, the list hears first. Unsubscribe anytime. You'll get one email to confirm first. Details

Bench camera still: an SO-101 robot arm on a cutting mat with a black tool locked on its wrist and a rubber-banded wrist camera, with loose parts on the mat
Still from my bench camera on 10/27: the arm with a tool on it.

Where it stands

  • What it is. A master ring on the SO-101's wrist and a plate on each tool. Three steel pins on the tool drop into steel V-notches when the wrist twists, and spring plungers hold them there. The body is 3D printed, with steel pins and springs.
  • What works. I've flown the arm by hand with its leader arm (teleop) and it has caught a tool out of the dock, locked it by twisting the wrist, and lifted it out a few times. The first was on 10/27, and that's the video below.
  • What doesn't yet. Automatic swaps. I've had a few scripted locks, and I've checked one of them by hand. It hasn't done a full pick up and put back on its own. The tool can jam coming out of the dock, so the dock is being redesigned, and parts are still changing.

The 10/27 catch

Real footage from 10/27, phone at the bench and wrist camera, flown by hand with a leader arm. Sped up where it says so on screen.

How the lock works

The tool slides onto the ring with its pins in three windows. Twisting the wrist rolls each pin up a ramp, compressing its spring, until it drops into a V made of two steel dowels. The springs keep it seated. Twist the other way and it lets go.

Tool changers for robot arms already exist, mostly industrial ones. This is my own small printed design for the SO-101.

Cutaway CAD render of the tool changer: a master ring on the wrist, a tool plate with three steel pins and spring plungers, and an unrolled diagram of one pin riding a ramp into a steel V-notch
CAD render. Cutaway made from my CAD model, not a photo.

Questions

Does it work?

Partly. A person flying the arm has caught a tool a few times. It can't swap by itself yet.

Can I buy one, or get the files?

Not now. There's no price and no date, and I haven't decided whether I'll release files or a kit. People on the list hear first.

Get tool changer updates

Build updates when something real happens, and the first word if I release files, a kit or a price.

A short welcome, then build updates on the SO-101 tool changer when something real happens (about two emails a month at most). If I ever release files, a kit or a price, the list hears first. Unsubscribe anytime. You'll get one email to confirm first. Details