Smart Blind Control System Overview

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General (prev)
Project
J2
Here’s a block-by-block rundown of the “Smart Blind Control System” reference design and how it all fits together:
1. Power Management
  • USB Type-C input via J2 provides a 5 V rail.
  • Reverse-protection diode D1 guards against accidental back-feeding or polarity errors on VBUS.
  • A 3.3 V LDO regulator U3 steps the USB 5 V down to power the ESP32 logic and the stepper driver’s internal logic.
  • A separate 5 V LDO U4 cleans up VBUS for the board’s 5 V logic/servo supply.
  • Decoupling capacitors on each rail keep both the microcontroller and motor-driver stable under load.
2. Microcontroller & User Interface
  • The brains is an ESP32-S3 mini module U1, which:
    • Runs your firmware (Wi-Fi/Bluetooth/USB) to receive commands.
    • Drives all stepper and servo control signals.
  • Three push-buttons let you manually BOOT, RESET, or put the ESP32 into Sleep mode (SW1, SW2, plus a “SLEEP” net button).
  • An on-board RGB status LED LED1 (with its series resistors) indicates power, mode, errors, or network status.
3. Stepper-Motor Drive
  • A standard A4988 stepper driver U2 receives STEP, DIR, and ENABLE signals from the ESP32 to spin a blind-shaft stepper.
  • Current-sense resistors and filter caps around the driver set the motor current limit and suppress switching noise.
  • Two screw-terminal blocks (J3 & J4) connect your stepper motor coils directly to the driver’s outputs.
4. Servo Control
  • Two 3-pin headers (J1 & J5) allow you to plug in standard hobby servos—ideal for tilting slats or slaving secondary actuators—powered by the board’s regulated 5 V.
5. USB & Firmware Programming
  • USB D+/D– lines from the Type-C port [J2] route straight to the ESP32’s USB-UART interface, letting you flash new firmware or communicate via serial.
  • CC-pin pulldown networks on CC1/CC2 auto-negotiate current draw so the board appears as a “device” to any USB host.
Overall Workflow:
  1. Power: Plug in a USB-C cable → board generates both 5 V and 3.3 V rails.
  2. Firmware: ESP32 boots from flash; you can reflash via USB or OTA over Wi-Fi/Bluetooth.
  3. Control Signals: Your app or home-automation hub issues blind-position commands.
  4. Motion: ESP32 toggles [U2] step/dir lines to raise/lower blinds; toggles servo outputs on [J1]/[J5] to tilt slats.
  5. Feedback: Status LED [LED1] shows errors or network status; buttons let you override or enter sleep mode.
This turnkey reference design lets you drop in any standard stepper motor and servos for a fully automated, Wi-Fi/Bluetooth-connected blinds controller.
CC pulldown values
ESP32 decoupling caps
Motor supply bulk cap
Set A4988 current
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ENABLE
STEP
U2
U1
MS1
DIR
LED_G
U3
ENABLE
USB_D-
+5V
LED_R
STEP
3V3
MS3
SLEEP
C1
Capacitance
0.1u F
LED_B
MS2
BOOT
DIR
EN
SERVO1
SLEEP
RESET
SERVO2
RESET
USB_D+
C5
Capacitance
1u F
  • Ground
    Ground
    A common return path for electric current. Commonly known as ground.
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    Net Portal
    Wirelessly connects nets on schematic. Used to organize schematics and separate functional blocks. To wirelessly connect net portals, give them same designator. #portal
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  • Power Net Portal
    Power Net Portal
    Wirelessly connects power nets on schematic. Identical to the net portal, but with a power symbol. Used to organize schematics and separate functional blocks. To wirelessly connect power net portals, give them the same designator. #portal #power
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  • Generic Resistor
    Generic Resistor
    A generic fixed resistor for rapid developing circuit topology. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard resistor values: 1.0Ω 10Ω 100Ω 1.0kΩ 10kΩ 100kΩ 1.0MΩ 1.1Ω 11Ω 110Ω 1.1kΩ 11kΩ 110kΩ 1.1MΩ 1.2Ω 12Ω 120Ω 1.2kΩ 12kΩ 120kΩ 1.2MΩ 1.3Ω 13Ω 130Ω 1.3kΩ 13kΩ 130kΩ 1.3MΩ 1.5Ω 15Ω 150Ω 1.5kΩ 15kΩ 150kΩ 1.5MΩ 1.6Ω 16Ω 160Ω 1.6kΩ 16kΩ 160kΩ 1.6MΩ 1.8Ω 18Ω 180Ω 1.8KΩ 18kΩ 180kΩ 1.8MΩ 2.0Ω 20Ω 200Ω 2.0kΩ 20kΩ 200kΩ 2.0MΩ 2.2Ω 22Ω 220Ω 2.2kΩ 22kΩ 220kΩ 2.2MΩ 2.4Ω 24Ω 240Ω 2.4kΩ 24kΩ 240kΩ 2.4MΩ 2.7Ω 27Ω 270Ω 2.7kΩ 27kΩ 270kΩ 2.7MΩ 3.0Ω 30Ω 300Ω 3.0KΩ 30KΩ 300KΩ 3.0MΩ 3.3Ω 33Ω 330Ω 3.3kΩ 33kΩ 330kΩ 3.3MΩ 3.6Ω 36Ω 360Ω 3.6kΩ 36kΩ 360kΩ 3.6MΩ 3.9Ω 39Ω 390Ω 3.9kΩ 39kΩ 390kΩ 3.9MΩ 4.3Ω 43Ω 430Ω 4.3kΩ 43KΩ 430KΩ 4.3MΩ 4.7Ω 47Ω 470Ω 4.7kΩ 47kΩ 470kΩ 4.7MΩ 5.1Ω 51Ω 510Ω 5.1kΩ 51kΩ 510kΩ 5.1MΩ 5.6Ω 56Ω 560Ω 5.6kΩ 56kΩ 560kΩ 5.6MΩ 6.2Ω 62Ω 620Ω 6.2kΩ 62KΩ 620KΩ 6.2MΩ 6.8Ω 68Ω 680Ω 6.8kΩ 68kΩ 680kΩ 6.8MΩ 7.5Ω 75Ω 750Ω 7.5kΩ 75kΩ 750kΩ 7.5MΩ 8.2Ω 82Ω 820Ω 8.2kΩ 82kΩ 820kΩ 8.2MΩ 9.1Ω 91Ω 910Ω 9.1kΩ 91kΩ 910kΩ 9.1MΩ #generics #CommonPartsLibrary
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    1.5M
  • Generic Capacitor
    Generic Capacitor
    A generic fixed capacitor ideal for rapid circuit topology development. You can choose between polarized and non-polarized types, its symbol and the footprint will automatically adapt based on your selection. Supported options include standard SMD sizes for ceramic capacitors (e.g., 0402, 0603, 0805), SMD sizes for aluminum electrolytic capacitors, and through-hole footprints for polarized capacitors. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard capacitor values: 1.0pF 10pF 100pF 1000pF 0.01uF 0.1uF 1.0uF 10uF 100uF 1000uF 10,000uF 1.1pF 11pF 110pF 1100pF 1.2pF 12pF 120pF 1200pF 1.3pF 13pF 130pF 1300pF 1.5pF 15pF 150pF 1500pF 0.015uF 0.15uF 1.5uF 15uF 150uF 1500uF 1.6pF 16pF 160pF 1600pF 1.8pF 18pF 180pF 1800pF 2.0pF 20pF 200pF 2000pF 2.2pF 22pF 20pF 2200pF 0.022uF 0.22uF 2.2uF 22uF 220uF 2200uF 2.4pF 24pF 240pF 2400pF 2.7pF 27pF 270pF 2700pF 3.0pF 30pF 300pF 3000pF 3.3pF 33pF 330pF 3300pF 0.033uF 0.33uF 3.3uF 33uF 330uF 3300uF 3.6pF 36pF 360pF 3600pF 3.9pF 39pF 390pF 3900pF 4.3pF 43pF 430pF 4300pF 4.7pF 47pF 470pF 4700pF 0.047uF 0.47uF 4.7uF 47uF 470uF 4700uF 5.1pF 51pF 510pF 5100pF 5.6pF 56pF 560pF 5600pF 6.2pF 62pF 620pF 6200pF 6.8pF 68pF 680pF 6800pF 0.068uF 0.68uF 6.8uF 68uF 680uF 6800uF 7.5pF 75pF 750pF 7500pF 8.2pF 82pF 820pF 8200pF 9.1pF 91pF 910pF 9100pF #generics #CommonPartsLibrary
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  • Generic Inductor
    Generic Inductor
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  • Terminal
    Terminal
    An electrical connector acting as reusable interface to a conductor and creating a point where external circuits can be connected.
    natarius
  • RMCF0805JT47K0
    RMCF0805JT47K0
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  • 875105359001
    875105359001
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  • CTL1206FYW1T
    CTL1206FYW1T
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Smart Blind Control System Reference Design

Smart Blind Control System Reference Design
Description

Created
Last updated by barracuda474
1 Contributor(s)
barracuda474

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