The robot sits in a chair beside a desk. A miniature laptop and a service bell sit on the desk in front of it. Five micro servos drive the pose; limits and channel IDs are in include/servos.h.
| Index | Servo | Motion | At min |
At max |
Safe range (°) |
|---|---|---|---|---|---|
| 0 | Head | Face up / down (pitch) | down | up | 80 – 100 (stock) |
| 1 | Neck | Head left / right (yaw) | right | left | 80 – 100 (stock) |
| 2 | Left hand | Hand up / down | up | down | 80 – 100 (stock) |
| 3 | Right hand | Hand up / down (inverted scale) | down | up | 80 – 100 (stock) |
| 4 | Body | Whole torso left / right | right | left | 80 – 100 (stock) |
Stock defaults match SERVO_SPECS in include/servos.h: 80°–100° on every joint when NVS is empty (mid 90°). After setup AP guided calibration the wider per-build limits are stored in NVS. Factory reset keeps the saved ranges. Retune them from the setup wizard servos hub (Calibrate servos) when AP mode is open, or Skip to keep the current values.
Animations author poses in −1..1 relative to each joint’s saved min/max (−1 = min, 0 = mid, +1 = max). Horn offset after assembly is absorbed by calibration; firmware maps those poses with servoNormToDeg. Right-hand rest is still electrical min (−1); left-hand rest is electrical max (+1).
Head tilts the face toward or away from the laptop. Neck pans the head side to side. Hands lift and lower over the keyboard; the forearms have no elbow servo — the arm linkage is fixed, so only the hand joint moves. Left and right hand servos use opposite scales: on the left, higher angle is down; on the right, higher angle is up (rest pose for typing is left at max, right at min — both over the keyboard). Setup AP guided calibration sets those keyboard bounds first, then the upper bounds. Body rotates the whole upper body in the chair while the base stays put.
Command a single joint for bench checks:
curl -X POST "http://tiny-engineer.local/test/servo" -H "Content-Type: application/json" -d '{"index":0,"angle":90}'Use angles inside the saved safe range on the assembled robot. During setup AP, POST /setup/servo can command the full 0–180° electrical range so you can find those limits.
Related: servos.md (PWM and electrical limits), api.md (/test/servo, /anim).