This project automates the opening and closing of roller blinds operated by a beaded chain, enhancing user convenience and accessibility. The system can be retrofitted to most existing chain operated blinds. It utilizes an ESP32-C6 microcontroller to control a DC motor to open, close, or move the blinds to specific positions. Users can interact with the system through several methods: tactile switches for manual operation, time-of-flight (ToF) sensor for proximity control, and a web interface for remote activation and configuring daily activation schedules. The system operates using a finite state machine with several distinct modes:
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Toggle Mode: Default operation mode where pressing the Open/Close buttons or proximity detection via the ToF sensor move the blinds to their configured positions.
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Manual Mode: Activated by a pressing the Mode button, allows for precise position control by holding the Open/Close buttons. The system automatically returns to Toggle Mode after a set timeout.
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Configuration Mode: Activated by holding the Mode button, allows the user to set the fully open and closed position limits into non-volatile memory by holding the Open/Close buttons. The system automatically returns to Toggle Mode after a set timeout.
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Microcontroller (ESP32-C6-DevKitC-1): The central processing unit, executing the main control loop and state machine logic. It manages peripherals via GPIO and I2C, handles networking tasks (Wi-Fi connection, Network Time Protocol (NTP) synchronization, web interface), reads the encoder with its internal Pulse Counter (PCNT) module, and controls the motor driver.
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DC Motor w/ Encoder (JGY-370-EN): A 158:1 geared DC motor that drives the physical movement of the blinds via the beaded chain. Its integrated quadrature encoder provides rotational feedback for precise position tracking.
- 3D-Printed Sprocket: Mechanically couples the motor shaft to the beaded chain with the correct pitch and
diameter. Model files available in
assets/.
- 3D-Printed Sprocket: Mechanically couples the motor shaft to the beaded chain with the correct pitch and
diameter. Model files available in
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Motor Driver (TB6612FNG): An H-bridge to control the DC motor since the ESP32's GPIO pins cannot supply enough current or voltage to directly power the motor. It receives PWM and direction signals from the ESP32, enabling forward, reverse, speed control, and braking.
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Time-of-Flight Sensor (VL53L0X): An I2C sensor for proximity detection to enable touchless operation. It checks if a user's hand gesture is within the range threshold, allowing the blinds to toggle between open/closed states or interrupt current movement.
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Timekeeping: It uses the ESP32's internal timer for scheduled remote activation, allowing the blinds to open or close automatically at user-defined times. Ihe timer periodically synchronized with an NTP server over Wi-FI to prevent drift.
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Web Interface: An asynchronous web server for remote control and configuration over Wi-Fi. Users can open or close their blinds and program the daily activation schedule without physical access to the device. The schedules are saved to the ESP32's non-volatile memory.
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Tactile Switches (SPST): Three momentary buttons that provide the primary means for manual opening/closing, switching between operational modes (Toggle, Manual, and Configuration), and setting the physical open/close limits during the setup process.
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RGB LED: It provides visual status feedback to the user, indicating the system's current state (Setup, Idle, Moving Open, Moving Close, Manual Mode, Config Open, Config Close, Config Save, and Error) and aiding in troubleshooting.
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Buck Converter: It converts the 12V input supply voltage to 5V in order to power the ESP32 and peripherals.
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ESP32-C6 Compatibility: Integrating the ESP32-C6 was challenging due to its novelty. A significant portion of development time was dedicated to utilizing the encoder as the board has newer PCNT harware. This involved creating a custom library (
ESP32PCNTEncoder) by navigating technical documentation and using an existing Arduino library as a baseline. -
Position Accuracy: Maintaining accurate encoder readings during rapid motor movements was challenging due to motor coasting at the target position. Adjusting the motor driver outputs to enable braking resolved the drift. Setting an appropriate position tolerance and saving the last known encoder position to memory helped prevent inaccuracies even after a power loss.
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State Machine Logic: Ensuring clean transitions between system states required careful debugging. Initially, the system occasionally skipped states upon button release. This was resolved by implementing boolean flags to correctly handle button events during specific state transitions. Managing timeouts for different modes also added complexity.
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Web Server & Persistence: Implementing the web server’s scheduler, parsing HTML form data, and reliably saving settings presented difficulties. Parsing the form required discovering the
sscanf()function. During debugging, it became clear that saving schedules was failing because the key names exceeded the maximum length allowed by the Preferences library.
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Target Application: Unlike products such as SwitchBot Curtain, which are designed for rail-based curtains moving horizontally, AutoBlinds specifically targets roller blinds operated by a vertical beaded chain.
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Installation & Cost: AutoBlinds is a cost-effective retrofit solution for existing beaded chain roller blinds, whereas many commercial motorized blind systems require a complete replacement of the window covering.
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Control Methods: Unlike many commercial options that rely on proprietary RF protocols or cloud services, AutoBlinds offers local network control via its web interface, enhancing user privacy and eliminating the need for app downloads. It also supports a wider range of control inputs, improving accessibility and operational independence.
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Power: AutoBlinds requires a wired 12V power source, whereas most commercial solutions typically offer battery-powered options.
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Motor Control: Implement a PID control loop for smoother, more precise movement, and develop an automatic calibration routine to detect blind position limits during initial setup.
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Scheduling: Implement per-day scheduling options and allow setting schedules based on sunrise and sunset times.
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User Interface: Develop a more sophisticated web interface with improved visual design, real-time status updates, and graphical blind position feedback/control.
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Security: Enhance the security of the web interface with basic authentication and HTTPS encryption to prevent unauthorized access.
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Over-the-Air (OTA) Updates: Implement OTA firmware updates via Wi-Fi to eliminate the need for physical access for reflashing.
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Enclosure: Create a 3D-printed enclosure and a custom PCB for the components for a smaller, aesthetically pleasing package.
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Power: Design a version that can be powered by rechargeable batteries, with appropriate power management (sleep modes, battery monitoring, and interrupts instead of polling).
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Preferences:
- Part of the Arduino Core for ESP32, used for non-volatile storage.
- License: LGPL-2.1 (github.com/espressif/arduino-esp32)
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ESP32PCNTEncoder (Custom Library):
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VL53L0X:
- Used for ToF sensor interfacing.
- Copyright:
- (C) 2017-2022 Pololu Corporation
- (C) 2016 STMicroelectronics International N.V.
- License: MIT+BSD-like (
.pio/.../VL53L0X/LICENSE.txt)
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WiFiManager:
- Used for Wi-Fi configuration.
- Copyright (C) 2015 tzapu
- License: MIT (
.pio/.../WiFiManager/LICENSE)
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AsyncTCP:
- Used for asynchronous TCP communication.
- Copyright (C) 2016-2025 Hristo Gochkov, Mathieu Carbou, Emil Muratov
- License: LGPL-3.0 (
.pio/.../AsyncTCP/LICENSE)
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ESPAsyncWebServer:
- Used for running the asynchronous web server.
- Copyright (C) 2016-2025 Hristo Gochkov, Mathieu Carbou, Emil Muratov
- License: LGPL-3.0
(
.pio/.../ESPAsyncWebServer/LICENSE)