Motorized Venetian Blinds

Tired of manually adjusting your venetian blinds?

If yes, here's a solution to automate your daily routine with a mobile app, allowing you to control the position of your venetian blinds wirelessly.

With just a few clicks, you can open or close the venetian blinds of a single window, a group of windows, or even all the blinds in your home. The system is compatible with Android smartphones and works seamlessly with conventional venetian blinds. Don't worry—manual operation remains an option as well!

At the top of each window frame, a totally concealed setup of a small step motor, PCB, Bluetooth module, and battery pack is installed. Using the app, your phone establishes a Bluetooth connection with each motorized blind, giving you full control over their position.

The battery is designed to last approximately 1–2 years, even with heavy use, such as opening and closing the blinds twice daily.

HARDWARE:

1. Electrical main board
2. Bluetooth module: BL652 Series Bluetooth v5 + NFC Module | Ezurio
3. Motor driver DRV8833PW datasheet
4. Bill of Material is listed in the attached BOM_v1.txt
5. Mechanical parts
6. DC5V 2-Phase 4-Wire Metal Gearbox Stepper Motor, e.g. ebay.com
7. Battery holder AA 4 cell, e.g. BH34AASF drawings
8. Battery connector snap, e.g. A strap catalog
9. 2 x 3D printed parts
10. paperclip
11. motor cable
12. thin copper wires
13. screw terminal of a wire connector
14. 2 x screws
15. 4 x AA batteries

SOFTWARE:

1. Smart basic FW in Bluetooth module
2. MIT App Inventor SW in Android mobile phone

The key components in the schematic are a linear voltage regulator, a Bluetooth module, and a motor driver. The purpose of the regulator is to convert the 6V input battery voltage from the J2 connector to 3.3V for the Bluetooth module. The motor driver is powered directly by the 6V battery supply. The Bluetooth module's 4 GPIO ports are connected to the motor driver to provide input signals for the step motor's movement. The motor driver's output ports are linked to the step motor via the J1 connector. Additionally, the J3 pin header enables the interface for programming the Bluetooth module.

The rectangular PCB size is 46 x 22 mm. It features a dual-layer stack-up, with all components soldered onto the top side. The bottom side serves as a solid ground plane. The right edge of the PCB includes a copper keep-out area to ensure optimal performance of the Bluetooth module's antenna.

Assemble the battery cable:

Assemble the motor cable:

Prepare the motor cable and solder A+, A- and B+, B- control wires to the step motor. Solder the GND wire to the chassis of the step motor. Secure all soldered connections with hot glue for stability. Leave the SIO-wires un-soldered at this phase. The length of the SIO wires are about 12 cm, all the other wires are approximately 6 cm.

Print the 3D parts

The size of the main 3D printed housing is approximately 50 x 24 x 25 mm (L x W x H).

Remove the screw terminal from a wire terminal

The screw terminal serves as the connection between the shaft of the venetian blind and the motor's shaft.

Bluetooth Module Firmware and Programming Instructions

The file $autorun$.kaihdin_v5p6.txt contains the firmware for the Bluetooth module. Rename the file from .txt to .sb before use. For detailed programming instructions, refer to BL652 Series Bluetooth v5 + NFC Module | Ezurio

Various USB-UART cables are available on the market; you may use your preferred model, but ensure that the output voltage of the cable is 3.3V. Here is one model for reference:

Programming the Bluetooth Module

1. Connect the debug cable to the programming pin headers (J3).
2. Plug in the battery cable.
3. Follow the programming procedure outlined in the Bluetooth module documentation.

MIT App Inventor SW in Android mobile phone

kaihdin_v2p3.aia contains the source code for the Android app. AIA files are not supported file type in this web page. This is the reason, why the code is shared only as a two overview pic captures. Basically the pics represent the entire phone-side code.

For more information about the Android app creation tool used in this project, visit the MIT App Inventor homepage.

The next image will describe the main screen and the button functionalities in detail.

The second screen is reserved for settings:

Assembly Instructions

1. Insert the step motor into the housing.
2. Place the red 3D-printed part into position.
3. Bend two paperclips and thread the straightened paperclips through the main housing.
4. Solder the SIO28 wire to the lower paperclip.
5. Solder the SIO29 wire to the upper paperclip.
6. Attach the screw terminal to the shaft of the step motor and tighten the screw.

Disclaimer

This product/service is provided "as is" without any guarantees or warranties of any kind, either express or implied. Use of this product/service is at your own risk. The creators, manufacturers, or distributors shall not be held responsible for any damages, losses, or issues arising from its use, including but not limited to physical, financial, or operational impacts. Please ensure compliance with local laws and regulations when using this product/service.

Final Installation and Testing

1. Open a window and slide the assembled housing onto the end of the venetian blind’s shaft.
2. Tighten the screw.
3. Manually check the movement of the venetian blind. If adjustments are needed, loosen the screw, reposition the shaft slightly, and tighten the screw again.
4. Repeat Step 3 until you are satisfied with the movement range.
5. Attach the main board to the housing and secure it with two screws.
6. Plug in the connectors and place the battery pack next to the housing.
7. Close the window and test the functionality of the system using the app.
8. If you want to reverse the rotation direction, enable the reverse checkbox in the app's settings screen.