6.8 KiB

Raw Blame History

DShotRMT - ESP32 RMT DShot Driver

An Arduino IDElibrary for generating DShot signals on ESP32 microcontrollers using the modern ESP-IDF 5 RMT encoder API (rmt_tx.h / rmt_rx.h). This library specifically leverages the official rmt_bytes_encoder API for an efficient, hardware-timed, and maintainable implementation. It provides a simple way to control brushless motors in both Arduino and ESP-IDF projects.

The legacy version using the old rmt.h API is available in the oldAPI branch.

DShot300 Example Output

Here's an example of the output from the dshot300 example sketch:

🚀 Core Features

Multiple DShot Modes: Supports DSHOT150, DSHOT300, DSHOT600, and DSHOT1200.
Bidirectional DShot Support: Implemented, but note that official support is limited due to potential instability and external hardware requirements. Use with caution.
Hardware-Timed Signals: Precise signal generation using the ESP32 RMT peripheral, ensuring stable and reliable motor control.
Simple API: Easy-to-use C++ class with intuitive methods like sendThrottlePercent().
Error Handling: Provides detailed feedback on operation success or failure via dshot_result_t.
Lightweight: The core library has no external dependencies.
Arduino and ESP-IDF Compatible: Can be used in both Arduino and ESP-IDF projects.

⏱️ DShot Timing Information

The DShot protocol defines specific timing characteristics for each mode. The following table outlines the bit length, T1H (high time for a '1' bit), T0H (high time for a '0' bit), and frame length for the supported DShot modes:

DShot Mode	Bit Length (µs)	T1H Length (µs)	T0H Length (µs)	Frame Length (µs)
DSHOT150	6.67	5.00	2.50	106.72
DSHOT300	3.33	2.50	1.25	53.28
DSHOT600	1.67	1.25	0.625	26.72
DSHOT1200	0.83	0.67	0.335	13.28

📦 Installation

Arduino IDE

Open the Arduino Library Manager (Sketch > Include Library > Manage Libraries...).
Search for "DShotRMT" and click "Install".
Alternatively, you can clone this repository or download it as a ZIP file and place it in your Arduino libraries folder (~/Arduino/libraries/DShotRMT/).

⚡ Quick Start

Here's a basic example of how to use the DShotRMT library to control a motor. Please use example sketches for more detailes:

#include <Arduino.h>
#include <DShotRMT.h> // Include the DShotRMT library

// Define the GPIO pin connected to the motor ESC
const gpio_num_t MOTOR_PIN = GPIO_NUM_27;

// Create a DShotRMT instance for DSHOT300
DShotRMT motor(MOTOR_PIN, DSHOT300);

void setup() {
  Serial.begin(115200);

  // Initialize the DShot motor
  motor.begin();

  // Print CPU Info
  printCpuInfo(Serial);

  Serial.println("Motor initialized. Ramping up to 25% throttle...");
  
}

void loop() {
  // Ramp up to 25% throttle over 2.5 seconds
  for (int i = 0; i <= 25; i++) {
    motor.sendThrottlePercent(i);
    delay(100);
  }
  
  Serial.println("Stopping motor.");
  motor.sendThrottlePercent(0);

  // Print DShot Info
  printDShotInfo(motor, Serial);
}

🎮 Examples

The examples folder contains more advanced examples:

throttle_percent: A focused example showing how to control motor speed using percentage values (0-100) via the serial monitor.
dshot300: A more advanced example demonstrating how to send raw DShot commands and receive telemetry via the serial monitor.
web_control: A full-featured web application for controlling a motor from a web browser. It creates a WiFi access point and serves a web page with a throttle slider and arming switch.
web_client: A variation of the web_control example that connects to an existing WiFi network instead of creating its own access point.

Dependencies for Web Examples

The web_control and web_client examples require the following additional libraries:

📚 API Reference

The main class is DShotRMT. Here are the most important methods:

DShotRMT(gpio_num_t gpio, dshot_mode_t mode = DSHOT300, bool is_bidirectional = false, uint16_t magnet_count = DEFAULT_MOTOR_MAGNET_COUNT): Constructor to create a new DShotRMT instance.
begin(): Initializes the DShot RMT channels and encoder.
sendThrottlePercent(float percent): Sends a throttle value as a percentage (0.0-100.0) to the ESC.
sendThrottle(uint16_t throttle): Sends a raw throttle value (48-2047) to the ESC. A value of 0 sends a motor stop command.
sendCommand(uint16_t command): Sends a single DShot command (0-47) to the ESC.
sendCommand(dshotCommands_e dshot_command, uint16_t repeat_count = DEFAULT_CMD_REPEAT_COUNT, uint16_t delay_us = DEFAULT_CMD_DELAY_US): Sends a DShot command multiple times with a delay between repetitions. This is a blocking function.
getTelemetry(uint16_t magnet_count = 0): Retrieves telemetry data from the ESC. If magnet_count is 0, uses the stored motor magnet count.
getESCInfo(): Sends a command to the ESC to request ESC information.
setMotorSpinDirection(bool reversed): Sets the motor spin direction. true for reversed, false for normal.
saveESCSettings(): Sends a command to the ESC to save its current settings. Use with caution as this writes to ESC's non-volatile memory.
printDShotResult(dshot_result_t &result, Stream &output = Serial): Prints the result of a DShot operation to the specified output stream.
printDShotInfo(const DShotRMT &dshot_rmt, Stream &output = Serial): Prints detailed DShot signal information for a given DShotRMT instance.
printCpuInfo(Stream &output = Serial): Prints detailed CPU information.
setMotorMagnetCount(uint16_t magnet_count): Sets the motor magnet count for RPM calculation.
getMode(): Gets the current DShot mode.
isBidirectional(): Checks if bidirectional DShot is enabled.
getEncodedFrameValue(): Gets the last encoded DShot frame value.
getThrottleValue(): Gets the last transmitted throttle value.

🤝 Contributing

Contributions are welcome! Please fork the repository, create a feature branch, and submit a pull request.

📄 License

This project is licensed under the MIT License. See the LICENSE file for details.

6.8 KiB Raw Blame History