# Building an expressive robot head prototype, Ecko, with a Galaxy S10 and a RealMan robotic arm

- Source: Reddit r/humanoidrobotics
- Published: 2026-10-27T18:39:16.000Z
- RoboHot: https://robohot.news/en/items/qxgskyw5h6e2tfuj9xnh7gf05
- Original: https://www.reddit.com/r/humanoidrobotics/comments/1xh0utx/prototyping_an_expressive_robot_face_with_a/

## Summary

A developer built an expressive head prototype, Ecko, using a Galaxy S10 paired with a RealMan robotic arm; it is not a complete humanoid robot. The phone provides animated eyes, a camera, a microphone, and a speaker, with ARCore facial landmarks drawn inside the eyes. A Mac backend handles arm movement and Gemini-driven conversation, and displays real-time joint telemetry in a digital twin. Face tracking works within a limited range; the first motion stopped after about seven seconds due to a sign error, and that failure was kept in the build video.