• Indoor desk use beside a Windows computer.
• One-off modular prototype using readily available development boards and modules.
• Connected to Hermes Agent Desktop through a small local plugin or companion application.
• Intended for learning, experimentation, and expressive AI interaction rather than unattended or safety-critical operation.

• Display animated eyes, an optional mouth, and optional status information.
• Turn its head approximately 45 degrees left and right.
• Raise and lower its left and right arms independently.
• React to Hermes states such as listening, thinking, speaking, tool activity, success, and errors.
• Offer a fallback reactive mode based on microphone activity and USB/connection state.
• Appear in Windows as a standard USB microphone and speaker.
• Allow Windows/Hermes to use either the robot audio devices or separate computer audio devices.

• Verified Adafruit SPI TFT LCD Display Touch ILI9341 module, 2.8-inch, 240 x 320 pixels (Flux part UID 86457530-204e-4e30-9ac7-55b0be369132), mounted landscape for a 320 x 240 face.
• Three micro servos: one head and one for each shoulder.
• USB audio with microphone input and speaker output.
• USB serial or HID control channel for expressions and motion commands.
• Two-cable power arrangement for reliability:
  • USB data/electronics cable from the computer.
  • Dedicated 5 V USB servo-power cable.
• 3D-printed body, 6–8 inches (15–20 cm) tall, with no legs.

Text
Windows PC / Hermes Agent
          |
          | USB data + electronics power
          v
   Internal USB 2.0 hub
      |             |
      v             v
USB audio module   RP2040 controller
(mic + playback)    |       |
      |              |       +--> Adafruit 2.8-inch ILI9341 SPI touchscreen
      |              +----------> 3 servo control signals
      v
Microphones + small audio amplifier + speaker

Dedicated 5 V USB servo supply
          |
          +--> fuse/protection --> bulk filtering --> 3 micro servos
                                      |
                                      +--> common ground with controller

• Native USB device support for a serial or HID command channel.
• Adequate SPI performance for a small animated TFT.
• Enough PWM/GPIO resources for three servos.
• Good Arduino and CircuitPython ecosystem for a learning-focused prototype.

1. Animated eyes only.
2. Eyes and mouth.
3. Expressions plus compact status text/icons.

• Three 9 g micro servos.
• Metal-geared MG90S-class servos are preferred for durability, subject to mechanical load testing.
• Head travel limited in firmware and mechanically to approximately ±45 degrees.
• Each shoulder provides one degree of freedom: arm raise/lower.
• Firmware must use eased acceleration and avoid commanding all servos to reverse abruptly at once.

• Windows class-compliant USB audio.
• Two or more microphones.
• Acoustic echo cancellation, noise suppression, and voice activity detection where available.
• Playback output suitable for feeding a small amplifier.

• Small 4 ohm or 8 ohm speaker in the body.
• Compact class-D amplifier module driven by the USB audio module’s analog playback output, if that output is available on the selected module.
• Physical or software volume control is desirable.
• Speaker placement and microphone isolation must minimize acoustic feedback.

• Approved FE1.1s USB 2.0 four-port hub, bus-powered from DATA_5V.
• One protected upstream pair from the Windows PC.
• Two populated protected downstream pairs: Raspberry Pi Pico SC0915 and CM108B. Unused hub ports are intentionally not populated.
• Every used USB D+/D- pair has USBLC6-2SC6 protection placed connector-side before hub/device circuitry.

• Separate 5 V USB input rated for at least 3 A.
• Selected fuse: F2 Bel Fuse 0ZCF0300AF2C, resettable PPTC, 2920 SMD, 15 Vdc, 3.00 A hold / 5.20 A trip at 23°C. SMD050F-2 remains prohibited on SERVO_5V because its 0.50 A hold rating cannot pass this rail.
• Reverse-current/backfeed prevention between the servo input and computer USB power.
• Installed bulk: two Chemi-Con EMZS250ARA102MJA0G low-ESR SMD aluminum electrolytics, 1000 uF/25 V each (2000 uF total), 60 mOhm max ESR and 1.19 A rated ripple each at 105 C/100 kHz, plus local ceramic bypassing.
• Common ground between servo supply and controller; 5 V power rails remain isolated from each other.

• The robot is always tethered; no battery is planned.
• Data-side electronics should target no more than 500 mA from a conventional USB port unless the selected hub and computer connection explicitly support more.
• Servo supply should be a regulated 5 V, 3 A USB wall adapter or equivalent dedicated source.

• Hermes Desktop supports Windows, voice mode, plugins, WebSocket/JSON-RPC integration, and lifecycle hooks.
• Recommended software arrangement:
  1. A Hermes plugin or local companion application observes lifecycle events.
  2. It maps events to a small robot state model.
  3. It sends concise commands over USB serial or HID.
  4. The robot firmware performs animations locally.
• Proposed high-level states: idle, listening, thinking, speaking, tool-working, success, warning, error, disconnected, and manual-demo.
• Standalone reactive mode uses audio activity and connection status when Hermes events are unavailable.

Text
STATE THINKING
STATE SPEAKING
FACE HAPPY
FACE EYES_ONLY
ARM LEFT 70
ARM BOTH WAVE
HEAD -30
BRIGHTNESS 60
MODE REACTIVE

• Revision 1 uses modules and hand wiring rather than a custom all-in-one PCB.
• Use keyed or clearly labeled connectors for the servos and power inputs.
• Use strain relief on both USB cables.
• Provide access to the RP2040 reset/boot controls and USB connector.
• The body should be serviceable with screws; avoid permanently glued electronics.
• A later revision may replace the wiring with a small carrier/interconnect PCB.

• Store neutral positions and motion limits for each servo.
• Smooth motion profiles to reduce noise and current spikes.
• Watchdog or timeout that returns servos to a safe neutral pose after lost communication.
• Non-blocking display and servo animation.
• USB command parser with acknowledgments and version reporting.
• Configurable face modes and screen brightness.
• Manual demo/reactive mode independent of Hermes.

• Overall height: 6–8 inches (15–20 cm).
• 3D-printed head, torso, and two arms; no legs.
• Screen forms most of the front face.
• Head rotates around a vertical axis with ±45-degree travel.
• Arms rotate at the shoulders to raise/lower independently.
• Microphones need unobstructed acoustic openings away from the speaker.
• Internal structure must provide rigid servo mounts, wire clearances, cable strain relief, and access for assembly.
• The body should have enough mass or a weighted base to resist tipping when both arms move.

• Approved: Replace all planned/unverified 2.4-inch TFT references with the verified Adafruit 2.8-inch ILI9341 SPI touchscreen module, Flux part UID 86457530-204e-4e30-9ac7-55b0be369132.
• Approved module set for the first-pass carrier schematic: Raspberry Pi Pico SC0915, FE1.1s USB hub, CM108B USB audio, the verified Adafruit display, and three 1x3 servo headers.
• USB protection is mandatory: USBLC6-2SC6 on the hub upstream pair and on each populated downstream pair (Pico and CM108B), connector-side before the protected IC/module; SMD050F-2 plus SMF5.0A on DATA_5V; SMF5.0A on SERVO_5V with the higher-current fuse selection left open.
• Servo interface: three external MG90S-class servos connect through independent 1x3 2.54 mm headers, each carrying GND, SERVO_5V, and one dedicated Pico PWM GPIO.
• DATA_5V supplies hub/controller/display/audio only and must remain within the negotiated USB source limit; SERVO_5V is a separate 5 V/3 A input. The rails share GND only and must never be tied together.
• The Windows computer performs all AI and speech processing.
• The robot is a USB peripheral rather than a standalone AI computer.
• The first prototype uses off-the-shelf modules.
• Reliability takes priority over a single cable, so servo power uses a second USB cable.
• One data cable still carries both robot control and USB audio through an internal hub.
• Audio input/output and external computer audio remain selectable options.

• Hermes lifecycle hooks/plugin APIs available in the installed version are sufficient to derive the desired animation states.
• A currently supported ReSpeaker/XMOS module with Windows USB audio and playback capability will be available.
• The printed head and arms are lightweight enough for genuine MG90S-class servos.
• The user has access to a 3D printer and a regulated 5 V/3 A USB power adapter.
• The first enclosure can be adjusted after fit and acoustic testing.

• Windows detects the robot controller and USB audio without a custom kernel driver.
• Hermes events trigger visible expressions and motions with acceptable latency.
• Robot microphone works for understandable near-field speech.
• Robot speaker can play Hermes speech without unstable feedback at normal desk volume.
• Simultaneous servo motion does not reset or disconnect the controller/audio devices.
• Head and arm motion remain within safe mechanical limits.
• Robot remains stable on the desk during normal gestures.

1. Bench-validate F2 0ZCF0300AF2C temperature rise and nuisance-trip margin with three real servos in the enclosure; the fuse selection and schematic implementation are complete.
2. Measure or obtain guaranteed current consumption for the selected TFT/backlight and complete DATA_5V enumeration/current-budget validation.
3. Estimate printed head/arm mass and confirm MG90S torque margin.
4. Decide whether USB serial or HID is the preferred robot command transport after a small Windows/Hermes proof of concept.
5. Confirm CM108B C12 VREF capacitance from a legible official reference schematic; the datasheet mandates decoupling but the searched application-note text did not expose a numeric value. C12 remains 1 uF and is explicitly not release-confirmed. C13 VBIAS=1 uF and the 100 nF AVDD/DVDD local bypass values are also retained as engineering defaults pending authoritative numeric confirmation.

• Rev 0.4: Selected and implemented F2 Bel Fuse 0ZCF0300AF2C (2920 resettable PPTC) between J7 raw VBUS and protected SERVO_5V; retained D3 SMF5.0A on the protected side; documented electrical ratings, voltage drop, transient behavior, and thermal-derating limitation.
• Rev 0.3: Locked SC0915, FE1.1s, CM108B, verified Adafruit 2.8-inch 240x320 ILI9341 SPI touch display, three external MG90S-class servo headers, DATA_5V/SERVO_5V isolation, per-pair USBLC6-2SC6 protection, and per-input TVS protection. Restricted SMD050F-2 to DATA_5V and recorded the required higher-current SERVO_5V fuse as an open safety item.
• Rev 0.2: Approved the verified Flux library Adafruit 2.8-inch ILI9341 SPI touchscreen (UID 86457530-204e-4e30-9ac7-55b0be369132) and replaced every earlier 2.4-inch display reference; fixed the first-pass module set and explicitly preserved separate DATA_5V and SERVO_5V domains.
• Rev 0.1: Captured the agreed 6–8 inch, Windows-connected Hermes robot concept; selected the modular two-cable architecture; added preliminary module directions, power budget, integration approach, and prototype success criteria.