blinds

SinricPro Motorized Blinds Example

Control window blinds/curtains with voice commands using DC motor or stepper motor.

Hardware

• ESP32 board
• DC motor or stepper motor
• Motor driver (L298N, L293D, or DRV8825 for stepper)
• External power supply (12V for most motors)
• Manual control buttons (optional)

Wiring

Using L298N Motor Driver

ESP32 GPIO25 → IN1 (Motor direction)
ESP32 GPIO26 → IN2 (Motor direction)
ESP32 GPIO27 → ENA (Motor enable)
ESP32 GND    → GND

L298N OUT1   → Motor +
L298N OUT2   → Motor -
L298N +12V   → External 12V supply
L298N GND    → Power supply GND + ESP32 GND (common ground)

Buttons:
ESP32 GPIO32 → UP button → GND
ESP32 GPIO33 → DOWN button → GND
ESP32 GPIO0  → STOP button (BOOT) → GND

Features

• Variable position control 0-100% (0=closed, 100=open)
• Automatic motor control with position tracking
• Manual buttons (up/down/stop)
• Smooth movement to target position
• Position reporting to SinricPro

Build

cd examples/blinds
idf.py build flash monitor

Configuration

Edit main/blinds_example.c - update WiFi and SinricPro credentials.

IMPORTANT: Calibrate travel time for your blinds:

#define FULL_TRAVEL_TIME_MS (10000)  /* Adjust: Time from fully closed to fully open */

To calibrate:

1. Measure time for full open→close cycle
2. Set FULL_TRAVEL_TIME_MS to this value
3. Test accuracy, adjust if needed

Voice Commands

• "Alexa, open the blinds"
• "Alexa, close the blinds"
• "Alexa, set blinds to 50 percent"
• "Alexa, open the blinds halfway"

Motor Control Methods

Method 1: DC Motor (Simple)

• Pros: Simple, cheap
• Cons: No position feedback, relies on timing
• Use with: L298N, L293D
• This example uses timing-based position estimation

Method 2: Stepper Motor (Accurate)

• Pros: Precise position control, no drift
• Cons: More expensive, noisier
• Use with: DRV8825, A4988
• Modify code to use step counting instead of timing

Method 3: Servo Motor

• Pros: Built-in position control
• Cons: Limited rotation (180° max)
• Use for: Small blinds, shutters
• See examples/lock for servo code

Position Tracking

This example uses time-based estimation:

• Tracks motor runtime to estimate position
• Works well for consistent loads
• May drift over time (periodic recalibration recommended)

For better accuracy, add:

• Limit switches (detect fully open/closed)
• Rotary encoder (measure actual rotation)
• Current sensor (detect motor stall)

Safety Features

IMPORTANT: Motorized blinds can be dangerous.

1. Obstruction Detection: Add current sensing to detect obstructions
2. Limit Switches: Prevent over-travel
3. Thermal Protection: Motor drivers can overheat
4. Manual Override: Always provide manual operation method

Manual Buttons

• UP: Move to fully open (100%)
• DOWN: Move to fully closed (0%)
• STOP: Stop at current position

Installation Tips

1. Motor Selection:

   • Calculate blind weight
   • Choose motor with 2-3x torque margin
   • Consider gearing for heavy blinds

2. Mounting:

   • Secure motor to wall/ceiling
   • Ensure smooth pulley/cord system
   • Test for binding or friction

3. Power Supply:

   • Size for motor current + margin
   • Use adequate gauge wire
   • Common ground is essential

Troubleshooting

• Motor doesn't move: Check power supply, wiring polarity
• Wrong direction: Swap IN1/IN2 connections
• Position drift: Recalibrate FULL_TRAVEL_TIME_MS
• Erratic movement: Check common ground connection
• Motor stalls: Increase voltage or reduce load

Advanced Features

Consider adding:

1. Scheduling: Open at sunrise, close at sunset
2. Light sensor: Automatic control based on sunlight
3. Group control: Control multiple blinds together
4. Privacy mode: Automatically close at night

Alternative Hardware

This example can be adapted for:

• Curtains: Horizontal track systems
• Roller shades: Tube motor systems
• Venetian blinds: Tilt angle control
• Shutters: Open/close control

Limit Switch Integration

Add limit switches for accurate calibration:

#define LIMIT_OPEN_GPIO   (34)
#define LIMIT_CLOSED_GPIO (35)

void check_limit_switches() {
    if (!gpio_get_level(LIMIT_CLOSED_GPIO)) {
        blinds_position = 0;  /* Recalibrate at closed */
        set_motor_direction(MOTOR_STOP);
    }
    if (!gpio_get_level(LIMIT_OPEN_GPIO)) {
        blinds_position = 100;  /* Recalibrate at open */
        set_motor_direction(MOTOR_STOP);
    }
}

Power Consumption

Typical DC motor blinds:

• Motor: 1-3A @ 12V during movement
• Idle: <50mA
• ESP32: ~150mA

Use appropriate power supply (recommend 12V 3A minimum).