This project uses an ESP32-based controller, stepper motors, TMC2209 (or similar) drivers and endstop switches (from a 3d printer kit) to control the circular Air Conditioner vents used in many ducted HVAC systems. Each board can control up to 4 vents (leave the stepper header empty and tweak the /AC_Vent/config.h to control fewer vents). Multiple boards can be utilised to control more vents, or for vents too far from one board.
This project is part of a larger ecosystem, designed to enable automation of vents based on the room temperatures, along with an App for manual control.
- home-app-backend - backend API and automation logic
- home-control - web app for manual control
- ESP32 Dev Board (NodeMCU-ESP32 DEVKITV1 - 30 pins - based on ESP-WROOM-32)
- 3D Printer Kit (from ebay or Aliexpress)
- 4x Nema 17 stepper motors + cables
- 4x Nema 17 mounting brackets
- 4x Stepper motors drivers - A4988 or DRV8825 or TMC2208 (for quieter operation)
- 4x RAMPS 1.4 switch endstops + cables (Note, swap the trigger switch for a waterproof one for more reliable operation, but keep the switch PCB)
- Order the PCB from the Gerber files (or custom-build with Perfboard 24 x 18 pins)
- 4x 150mm Lead screws + copper nuts (4mm pitch ideal, but any will work)
- DC-DC Buck convertor TRS2433 (or you can use an LM2596 set to 3.3v if DIYing the board)
- DC power supply (8-35 V)
- (optional) header-pin sockets for ESP32 and Stepper Drivers to allow quick removal/replacement
- A handfull of M4 screws & nuts
- Duct tape
- Order the custom PCM from the Gerber files in the Circuit Board V2/ directory.
- Print 4x Motor Bracket, Motor Cover, Endstop Clip in PLA or PETG (or other hard-plastic).
- Print 4x Coupler, Damper and 8x End Holder in TPU (for vibration damping - PLA will work in a pinch though). Metal couplers from a 3d printer kit can also be used.
- Assemble the circuitboard per the KiCad schematic or using the silk screen guides.
- Set the ventNames, microStepping, WiFi parameters in the firmware (see AC_Vent/README_CONFIG.md for details).
- Compile and flash the firmware onto your ESP32 dev board using Arduino IDE.
- Using USB for power (do not plug in the power supply for this).
- NOTE: Setup Arduino IDE with ESP32 library like this: https://randomnerdtutorials.com/installing-the-esp32-board-in-arduino-ide-windows-instructions/
- Bench test by connecting motors and endstop switches.
- You may need to switch the red and black wires on your endstop switches (black should be at the edge of the board, and red in the middle).
- Connect the power supply to the high-voltage side of the buck convertor. This will power up the ESP32.
- Tune the stepper motor current limit (Try this guide: https://www.makerguides.com/a4988-stepper-motor-driver-arduino-tutorial/).
- Using USB for power (do not plug in the power supply for this).
- On a computer, navigate to the IP Address of the device.
- Click to open one of the Vents.
- It will first spin counter-clockwise to close the vent until the endstop switch is triggered, then clockwise until the limit position is reached.
- Note: If the motor spins the wrong direction, simply unplug and reverse it's connector.
- Assemble components and install into vents. Tip: use Ethernet cable to extend leads as neccessary (I used RJ45 breakout modules but you could crimp connectors).
Note: There is no security or authentication in this system. Do not open up the port in your Router! For use on your internal network only.
Get vents status: GET http://192.168.2.110/?&t=1
Sample return:
{
"0": {
"name": "Room #1",
"pos": 30
},
"1": {
"name": "Room #2",
"pos": 60
},
"2": {
"name": "Room #3",
"pos": 100
}
}
Open vent #1 to 100%: GET http://192.168.2.110/?a=6&t=1&m=0&d=100
Here a is the operating mode, where mode 6 corresponds to: open to ratio set by &d= (eg. ?d=050:open50%, ?d=000:close, ?d=100:open100%).
Also, t is the response type (1 = JSON).
And, m is the motor number (0-2).
The return format is identical to the 'get status' request.
Note: Some photos are from the prototype.
