ESP32 Owl Companion

An interactive owl statue project powered by ESP32-C3, featuring motion, light, sound, and haptic feedback.

Garden Watch Visualization

The Garden Watch system monitors garden activity patterns to detect potential health concerns.

Overview

This project combines art and technology to create an interactive steel owl statue with the following capabilities:

• Head nodding motion via servo
• LED illuminated eyes with WS2812B rings
• Sound playback (owl hooting)
• Vibration haptic feedback
• Battery powered operation with deep sleep support
• HTTP-based remote control

The owl is designed with a detachable head that connects via magnetic pogo pins, allowing for modular design and easy maintenance. The statue features a bronze/copper-colored finish with a modern interpretative design.

Hardware Components

The project uses the following main components:

• M5Stamp C3U: ESP32-C3 RISC-V MCU controller module with Wi-Fi
• StampTimerPower: Power management module with battery charging, RTC, and power control
• WS2812B LED Rings (optional): 8-LED 5V rings for the owl's eyes
• MAX98357A Amplifier: I2S audio amplifier for the speaker
• 28mm Speaker: For sound output
• Vibration Motor: DC 3V-6V, 32mA for haptic feedback
• Servo Motor: For head nodding motion (15° forward, 10° back)
• 4-pin Magnetic Pogo Connector: For detachable head connection
• LiPo Battery: 3.7V 1000mAh with JST connector
• Slide Switch: For power control

See the Bill of Materials for a complete parts list.

Physical Design

Owl Statue Specifications

• Total Height: 200mm
• Head Diameter: 100mm
• Body Top Diameter: 75mm
• Materials: Steel with bronze/copper-colored finish
• Features:
  • Detachable head via magnetic connection
  • Decorative base with radiating support legs
  • Contrasting black interior
  • Bowl-shaped body design
  • Large circular eye cutouts with LED illumination

System Architecture

The system uses a dual voltage design (3.3V and 5V) with the following subsystems:

Power System

• Battery charging via TP4057 on StampTimerPower
• 3.3V DCDC output for M5Stamp C3U
• 5V boost circuit for peripherals
• USB Type-C charging port
• Battery protection circuit

Head Section

• WS2812B LED rings powered by 5V (optional component, can be omitted if visual feedback is not needed)
• 4-pin magnetic pogo connector:
  • Pin 1: 5V (LED power)
  • Pin 2: GND (Common ground)
  • Pin 3: LED Data (3.3V)
  • Pin 4: Sensing/Head detection

Body Section

• Motion system with servo motor for nodding
• Audio system with MAX98357A amplifier and 28mm speaker
• Vibration motor controlled via MOSFET
• Power management and control logic

GPIO Assignment

ESP32-C3 GPIO Mapping:
GPIO2  → LED Ring Data (3.3V) [Optional - only if LED rings are installed]
GPIO6  → I2S BCLK
GPIO7  → I2S LRCLK
GPIO8  → I2S DIN
GPIO4  → Motor MOSFET (3.3V)
GPIO18 → I2C SDA (RTC)
GPIO19 → I2C SCL (RTC)
GPIO9  → Built-in Button
GPIO5  → Head Detection
GPIO10 → Servo Control

API Endpoints

The owl robot provides a comprehensive RESTful API for controlling all aspects of its functionality:

API Endpoint Overview

Endpoint	Method	Description
/	GET	Root endpoint that confirms server is running
/api/status	GET	Returns owl robot status including battery level and alert state
/api/hourly-data	POST	Receives hourly activity data from sensor modules
/api/control/motion	POST	Controls the nodding motion of the owl's head
/api/control/vibration	POST	Activates the vibration motor for haptic feedback
/api/control/audio	POST	Triggers sound playback
/api/control/led	POST	Controls the LED color
/api/action	POST	Activates the owl's action mode directly
/api/data/activity	GET	Returns garden activity data with baseline and deviation analysis
/api/data/daily-patterns	GET	Returns daily activity pattern data for healthy vs. current behavior
/api/data/weekly-tasks	GET	Returns weekly garden task completion data
/api/data/deviation	GET	Returns detailed deviation score analysis
/api/data/reminders	GET	Returns data on response times to garden care reminders

Detailed API Reference

1. Status Endpoint

Get the current status of the owl robot:

curl http://[OWL_IP_ADDRESS]/api/status

Example response:

{
  "status": "online",
  "batteryVoltage": 3.85,
  "recentActivity": 0.75,
  "alertActive": false
}

2. Hourly Data Endpoint

Send hourly activity data:

curl -X POST \
  http://[OWL_IP_ADDRESS]/api/hourly-data \
  -H 'Content-Type: application/json' \
  -d '{
    "timestamp": "2025-03-28 14:30:00",
    "hour": 14,
    "day": 5,
    "detectionCount": 12,
    "totalReadings": 15,
    "maxDetectionPoints": 8,
    "avgDetectionPoints": 3.5,
    "presenceRatio": 0.8
  }'

Parameters:

Field	Type	Description
timestamp	string	ISO formatted date and time when the hour period started
hour	integer	Hour of day (0-23) of the data collection period
day	integer	Day of week (0=Sunday, 1=Monday, ..., 6=Saturday)
detectionCount	integer	Number of readings that detected human presence
totalReadings	integer	Total number of sensor readings taken during the hour
maxDetectionPoints	integer	Maximum number of detection points recorded in any single reading
avgDetectionPoints	float	Average number of detection points across all readings
presenceRatio	float	Ratio of readings with detected presence to total readings (0.0-1.0)

3. Motion Control Endpoint

Control the nodding motion:

curl -X POST \
  http://[OWL_IP_ADDRESS]/api/control/motion \
  -H 'Content-Type: application/json' \
  -d '{
    "angle": 15,
    "duration": 1000,
    "immediate": false
  }'

Parameters:

• angle: Nodding angle in degrees (1-30)
• duration: Duration to hold the position in milliseconds
• immediate: If true, moves immediately; if false, uses smooth animation

4. Vibration Control Endpoint

Activate haptic feedback:

curl -X POST \
  http://[OWL_IP_ADDRESS]/api/control/vibration \
  -H 'Content-Type: application/json' \
  -d '{
    "intensity": 50,
    "duration": 500
  }'

Parameters:

• intensity: Vibration intensity (1-100)
• duration: Duration in milliseconds (50-2000)

5. Audio Control Endpoint

Play sounds:

curl -X POST \
  http://[OWL_IP_ADDRESS]/api/control/audio \
  -H 'Content-Type: application/json' \
  -d '{
    "pattern": "hoot",
    "volume": 75
  }'

Parameters:

• pattern: Sound pattern to play ("hoot" or "reminder")
• volume: Volume level (1-100)

6. LED Control Endpoint

Control the LED color:

curl -X POST \
  http://[OWL_IP_ADDRESS]/api/control/led \
  -H 'Content-Type: application/json' \
  -d '{
    "r": 255,
    "g": 0,
    "b": 0,
    "w": 0,
    "duration": 5000
  }'

Parameters:

• r, g, b, w: RGB+W color values (0-255)
• duration: Duration in milliseconds (0 for indefinite)

7. Action Mode Endpoint

Trigger action mode directly:

curl -X POST http://[OWL_IP_ADDRESS]/api/action

Response:

{
  "status": "ok",
  "message": "Action mode activated"
}

8. Garden Activity Data Endpoint

Get garden activity metrics:

curl http://[OWL_IP_ADDRESS]/api/data/activity

Example response (abbreviated):

[
  {
    "day": "Day 1",
    "actualActivity": 75,
    "baselineActivity": 80,
    "deviationScore": 0.25,
    "alert": false
  },
  {
    "day": "Day 2",
    "actualActivity": 78,
    "baselineActivity": 80,
    "deviationScore": 0.33,
    "alert": false
  },
  ... additional days ...
]

9. Daily Activity Patterns Endpoint

Get daily activity pattern data:

curl http://[OWL_IP_ADDRESS]/api/data/daily-patterns

Example response (abbreviated):

{
  "healthy": [
    {
      "hour": "0:00",
      "activity": 5
    },
    ... additional hours ...
  ],
  "current": [
    {
      "hour": "0:00",
      "activity": 20,
      "expectedActivity": 5
    },
    ... additional hours ...
  ]
}

10. Weekly Task Completion Endpoint

Get weekly garden task completion data:

curl http://[OWL_IP_ADDRESS]/api/data/weekly-tasks

Example response (abbreviated):

{
  "healthy": [
    {
      "day": "Mon",
      "tasksCompleted": 5,
      "gardenTime": 45
    },
    ... additional days ...
  ],
  "current": [
    {
      "day": "Mon",
      "tasksCompleted": 1,
      "gardenTime": 15
    },
    ... additional days ...
  ]
}

11. Deviation Score Endpoint

Get detailed deviation score analysis:

curl http://[OWL_IP_ADDRESS]/api/data/deviation

Example response (abbreviated):

[
  {
    "day": "Day 1",
    "deviationScore": 0.25,
    "alert": false
  },
  {
    "day": "Day 2",
    "deviationScore": 0.33,
    "alert": false
  },
  ... additional days ...
]

12. Reminder Response Endpoint

Get response time data for garden care reminders:

curl http://[OWL_IP_ADDRESS]/api/data/reminders

Example response:

[
  {
    "week": "Week 1",
    "responseTime": 12,
    "alert": false
  },
  {
    "week": "Week 2",
    "responseTime": 15,
    "alert": false
  },
  {
    "week": "Week 3",
    "responseTime": 35,
    "alert": true
  },
  {
    "week": "Week 4",
    "responseTime": 42,
    "alert": true
  }
]