Build log, field notes, and robotic experiments

The servos arrived, and the build went super smoothly. I’m inappropriately proud of my color scheme.

 And the servos Daisy chain together. So the anticipated wire fiasco was minimal.

On the digital side, Cursor did everything.

I gave it the web address for the LeRobot project and the SO-101 arm, and it planned the setup, installed everything we needed, and handheld me through the motor ID and calibration process.

FYI, it is highly advised to ID the servos before setting up the robot.

With surprisingly little troubleshooting, I was logged into my robot through a website and controlling the robot hand.

Kind of.

I never actually got the phone control working well. I troubleshot it with Cursor for way too long, but the best I ever got was three of the servos awkwardly reacting to the phone.

It also became pretty clear that doing anything requiring finesse using a cell phone, and especially controlling the gripper with a little slider on a touchscreen, was going to be impractical.

It was very cool to get the thing wiggling, but if I want anything resembling decent teleoperation, I’m going to need the leader arm.

That pushes back quality teleoperation until after Santi leaves, which is a little disappointing. But I think I properly compensated for abandoning my mechanical engineering degree pursuit.

Critically, the servos for the leader arm are not just 6 of the same servo. They have different gear ratios involved and apparently that’s important. You can buy full leader/follower kits with all the servos included, but you can’t just buy the leader-arm servo set as a simple bundle.

So now I’m ordering from the servo company in China, and naturally they don’t even have all the needed servos in the same warehouse. 

Moral of the story: just buy the full kit.

I’ve been watching the open-source project LeRobot for nearly a year now, and I’ve been seriously impressed by the VLA models coming out of it, particularly the Pi0.5.

Learn all about that project at huggingface.co/lerobot

The only reason I hadn’t jumped into a robotics project was to avoid yet another project that distracts me from the projects I should probably be working on.

But it’s Christmas break and Gabi’s older son Santi is coming to visit. He’s been studying mechanical engineering and working at a marine robotics company. Honestly, I don’t think I need a better excuse than that to finally jump into building an SO-101 robot arm.

And they’re cheap.

I’ve already got a Raspberry Pi 5, so all I really needed to buy were the servos, the servo bus, and a power cord, which was about $140 on amazon. I just started 3D printing the main arm.

There’s a “leader” teleoperator arm option that lets you control the follower arm. But since it’s a whole 2nd setup of servos (another $140) and they also say you can teleoperate it with your cell phone, I’m going to try the cell phone version first, as I already have one of those. 

So excited to have a robot to do my bidding!