PCB WLED Spec 7

Welcome to this wled Usermod ✨

This usermod enables connection of an ESP32C3 (you can build the firmware for other boards) to a flight controller , allowing users to select specific presets with a switch on their remote. Originally developed for Spec7 quads, this mod can be applied to any project where a preset needs to be activated based on a PWM signal received on a designated pin.

⚙️ How It Works

WLED is a project that allows easy control of addressable RGB lights. Our focus is on enabling users to switch between different presets set up in the WLED app using a physical switch on the controller. This is achieved by leveraging a built-in feature in Betaflight or Inav that generates a PWM (Pulse Width Modulation) signal on a specific pin—typically used for controlling servos. While we could have read data directly from the receiver, we opted for the PWM approach for several reasons outlined below.

Advantages and Disadvantages of Using PWM

Advantages:

• Compatible with Any Remote Protocol Supported by Betaflight: Allows flexibility across various remote protocols.
• Minimal Data Processing from Receiver: Only the PWM signal is processed, improving the program’s speed and efficiency.
• Standalone Use with PWM Receivers: Can operate as a standalone unit with just the controller and LEDs, without a flight controller (FC).
• Protocol Agnostic: No need to adapt to specific protocols, making the setup easily adaptable.
• Avoids UART Conflicts: WLED may interfere with LED-receiver communication, particularly when multiple UARTs are used (one for the receiver and one for LEDs), as adding a software serial port can consume significant processing power.

Disadvantages:

• Requires a Flight Controller or PWM Receiver: Cannot function as a standalone unit with just the receiver, ESP, and LEDs.
• Single-Channel Limitation: Multiple channels for selecting presets would require additional wiring and pins on the FC.
• Consumes a Pin on the Flight Controller: Typically, the LED pin is used, but additional motor pins may also be viable.

Advantages and Disadvantages of Direct Receiver Connection

Advantages:

• Access to Full Receiver Data: Allows use of multiple channels.
• Standalone Operation: Can function with just the receiver, ESP, and LEDs.
• No Flight Controller Pin Usage: Frees up all pins on the flight controller.

Disadvantages:

• Requires Soldering on Receiver Pads: Soldering two wires onto a single receiver pad can be cumbersome.
• Limited to One Remote Protocol: Only one remote protocol can be used in this configuration.
• Increased Processing Power Demand: Requires significant processing resources, potentially impacting performance.

Conclusion

Considering these factors, we chose the PWM option, which offers a balanced approach in terms of flexibility, performance, and ease of setup. For instructions on setting up the system, refer to the Quick Start Guide.

💡 Quick Start Guide

Betaflight Setup

1. Enable Servo on Flight Controller

Ensure you flash your flight controller with servo enabled.

2. Standard Flight Controller Setup

Set up your flight controller as you normally would.

3. Check Resource Pins in CLI

Open the CLI and paste the following command to display all resources and their pin assignments:

resource

Find resource LED_STRIP 1 in the output and note the pin number next to it (e.g., A08).

4. Reassign LED Strip Pin to Servo

Enter the following commands in the CLI to remove the LED strip assignment from this pin and assign it to Servo 1:

resource LED_STRIP none
resource SERVO 1 "your noted pin number from step 4"
save

5. Configure Servo Settings

Go to the Servo tab and adjust the settings marked in the red box in the image below. Only the channel associated with the button to switch presets needs to be adjusted here. In the Receiver tab, you can check which button corresponds to which action. (We recommend using a 6-button switch on your controller; however, other setups may work, although results may vary.)

Note: This configuration won’t work when connected to your computer unless “live mode” is enabled.

Hardware Setup

1. Connect Ground

Connect the ground on your flight controller to the ground on the ESP. This is mandatory, as it sets a shared reference.

2. Connect Data Pin

Connect the LED pin on your flight controller to gpio 2 on the ESP (make sure it's not pin 2, because on some boards they aren't the same). This wire carries the data.

3. Power the ESP and LEDs

Power the ESP as needed, and connect the LEDs like a standard WLED setup.

Note: The following diagram provides an example for wiring. Do not copy it exactly; please research how to power your ESP safely. We are not liable for any physical or material damage.

Custom PCB

Warning: this pcb has not yet been tested, you can find all of the design files under the folder pcb. You should check the pcb design befor ordering.

If you want to order and test this pcb, we have added an excel file that includes all of the components. The components can be ordered from mouser and JLCPCB. Feel free to use other components.

We recently introduced a custom PCB that integrates all the necessary components to run WLED on drones. This board includes a 5V@3A buck converter, capable of stepping down 3s-6s voltage to a stable 5V supply.

The PCB measures 29mm × 21mm, making it a perfect fit for a Spec7 quadcopter. Since only one side of the board is populated, you don’t need to worry about clearance on the mounting surface.

However, we highly recommend placing a layer of electrical tape beneath the PCB to prevent potential short circuits, as carbon fiber is conductive.

At its core, the board features an ESP32-C3, complete with all essential supporting components for power management and Wi-Fi transmission.

To simplify wiring, we've integrated a logic level converter, which shifts the ESP32-C3's 3.3V signal to 5V, ensuring proper operation of LED strips.

Additionally, we've included an extra GPIO pin, which can be used for:

• Receiving an input from the flight controller
• Connecting an additional LED strip

This extra GPIO is available as both a 3.3V pad and a 5V pad (via the logic level converter), allowing seamless integration with LED strips.

Below is the wiring diagram. Please note that your flight controller may vary, so be sure to check its specifications before wiring.

Note: you should have a common ground between the PCB and flight controller to ensure proper operation of the PCB.

ESP Setup

This guide covers setup on Windows only. (Linux users should be able to manage on their own. Mac users: consider upgrading your hardware! Just kidding 😊)

1. Download Firmware

   • Navigate to build_output/releases, select the appropriate folder for your board, and download the .bin firmware file.
   • For ESP32 devices, download the bootloader file located in .pio/build/your_board_here.

2. Set Up Programming Tool

   • Follow the steps in this guide to install Python. You may skip steps 4 and 7 as they are optional.
   • Once Python is installed, open Command Prompt (cmd) and run pip install esptool to install esptool.

3. Connect ESP to Computer

   • While holding the boot button on the ESP, plug it into your PC.
   • Open Device Manager and note the COM port your ESP is connected to.

4. Upload Firmware

Note: These commands should be executed in the Command Prompt (cmd) on your Windows PC. You do not need to run it as an administrator. If you're unsure how to open Command Prompt, click the Windows Start button, type cmd, and select the Command Prompt application. This will open a terminal where you can enter commands.

• First, install the bootloader:

  esptool -p com(your_com_port) -b 460800 write_flash 0x0 (path_to_bootloader_file)

  Example:

  esptool -p com13 -b 460800 write_flash 0x0 C:\Users\YourUser\Downloads\WLED-main\.pio\build\esp32c3dev\bootloader.bin

  • Once done, disconnect and reconnect the ESP while holding the boot button.

• Now, upload the firmware:

  esptool -p com(your_com_port) -b 460800 write_flash 0x10000 (path_to_firmware_file)

  Example:

  esptool -p com13 -b 460800 write_flash 0x10000 C:\Users\YourUser\Downloads\WLED-main\build_output\release\WLED_0.14.4_ESP32-C3.bin

• After completion, disconnect the ESP from your PC.

Final Steps

Set up WLED as usual, ensuring you create six presets to avoid errors when switching. This setup is compatible with six-button switches (e.g., Radiomaster Boxer and TX16s). Future updates will include support for two- and three-position switches.

Enjoy your new LED setup on your Spec 7 quad!

Disclaimer:

If you are prone to photosensitive epilepsy, we recommended you do not use this software.
If you still want to try, don't use strobe, lighting or noise modes or high effect speed settings.

As per the MIT license, I assume no liability for any damage to you or any other person or equipment.