Inspiration
In an operating room, a scrub tech hands the surgeon each instrument the moment it is named and keeps count of everything on the tray. Hospitals cannot hire enough of them, and when no tech is free, the surgeon looks away from the patient to search the tray. Small and rural hospitals feel this the most, and they cannot afford multimillion-dollar surgical robots to make up for it.
What it does
Scrub is a robot arm that passes surgical instruments when you ask for them out loud. You say "hemostat" or "scalpel", and the arm picks it from the tray, holds it out handle first, and lets go when you pull it or say "let go". Saying "stop" freezes it immediately. Requests can come from a phone call or the station microphone, and Scrub asks which one you mean when a request is unclear. It logs every handoff and uses a camera to check the tray count. Scrub never touches the patient.
How we built it
The arm is an SO-101, a 3D-printed six-joint arm that costs about $250 in parts. We taught it each pick by guiding a matching leader arm by hand, recording video and joint positions, and trained it on those demonstrations with Perceptron's robot model. ElevenLabs handles speech through a Photon phone number, and Gemini turns each request into one command limited to instruments on the tray. Perceptron's vision API reads the tray and the count sheet. Events and motor temperatures go to MongoDB, and a public status page runs on Vultr. A MuJoCo simulation lets us test the full flow without the hardware.
Challenges we ran into
The servos overheated while holding position, so we built a guard that rests the arm with the motors off before they get too hot. The gripper struggled to hold thin, smooth steel until we added jaw limits and magnets under the grip. Five arms were shared among about twenty teams, which made recording clean demonstrations the hardest constraint of the weekend.
Accomplishments that we are proud of
Scrub hands a real instrument into a person's hand on a spoken request, with a safety stop at every step, on hardware that costs about $250.
What we learned
Most of the work in a robot that people stand next to goes into what happens when something goes wrong: stopping, overheating, and letting go at the right moment.
What is next for Scrub
We plan to test Scrub with surgical staff, add an electromagnet so the arm can pick up returned instruments and set them back in their slots, and move to a medical-grade arm that runs under a sterile drape in the operating room.
