Wireless Servo control ESP32, ESPNOW

Projects Programming
1

Using a pair ESP-MROOM-32 controller board with a standard 5V servo communicating across ESPnow.

I have confirmed I am able to send data from the Broadcast to the Listener (master to slave) modules.

I would like to command the servo to change states upon a broadcast being received. Command boolean is always recieved as 1. This is likely similar to a button debounce, but my brain is struggling how to get the logic gates to work out when the boolean is always 1.

Attached is the Reciever code.

#include <esp_now.h>
#include <WiFi.h>
#include <ESP32Servo.h>

// Structure example to receive data
// Must match the sender structure


typedef struct test_struct {
  bool command;
} test_struct;


// Create a struct_message called myData
test_struct myData;

//define Servo parameters
Servo myServo;
bool pos = 1;
bool oldpos;


#define SERVO_PIN 13

// callback function that will be executed when data is received
void OnDataRecv(const uint8_t * mac, const uint8_t *incomingData, int len) {
  /// identifies button pressed
 if (len == sizeof(myData)) {
    memcpy(&myData, incomingData, sizeof(myData));
    Serial.println(myData.command); //We got a command
       if (pos = 1){
        myServo.write(90); //move servo down
        pos = 0;
       }else{
        myServo.write(0); //move servo up
        pos = 1;
       }
  } else {
    Serial.println("Error: Incorrect data length");
  }

}
 
void setup() {
  // Initialize Serial Monitor
  Serial.begin(115200);
  
  // Set device as a Wi-Fi Station
  WiFi.mode(WIFI_STA);

  //setup Servo
  	// Allow allocation of all timers
	ESP32PWM::allocateTimer(0);
	ESP32PWM::allocateTimer(1);
	ESP32PWM::allocateTimer(2);
	ESP32PWM::allocateTimer(3);
	myServo.setPeriodHertz(50);    // standard 50 hz servo
	myServo.attach(SERVO_PIN, 500, 2400); // attaches the servo on pin 18 to the servo object
	// using default min/max of 1000us and 2000us
	// different servos may require different min/max settings
	// for an accurate 0 to 180 sweep

  // Init ESP-NOW
  if (esp_now_init() != ESP_OK) {
    Serial.println("Error initializing ESP-NOW");
    return;
  }
  
  // Once ESPNow is successfully Init, we will register for recv CB to
  // get recv packer info
  esp_now_register_recv_cb(esp_now_recv_cb_t(OnDataRecv));
}
 
void loop() {
// consistently ping for command from button
esp_now_register_recv_cb(esp_now_recv_cb_t(OnDataRecv));
}
2

Booleans are ALWAYS either true or are false.

4

the command boolean is just nonsense content in the sent packet. So yes its 1.

I want to have the servo action occur upon data packet receipt.

5

The above line has several errors. Among those errors, "==" is used for logical comparison.

6

Why try to obfuscate your postings on the forun?

7

Got it figured out using a register for position

#include <esp_now.h>
#include <WiFi.h>
#include <ESP32Servo.h>

// Structure to receive data
typedef struct test_struct {
  bool command;
} test_struct;

// Create a struct_message called myData
test_struct myData;

// Define Servo parameters
Servo myServo;
#define SERVO_PIN 13
int lastPos = 0;  // Track the last position of the servo

// Callback function that will be executed when data is received
void OnDataRecv(const esp_now_recv_info* recvInfo, const uint8_t* incomingData, int len) {
  // Check if the incoming data is the expected size
  if (len == sizeof(myData)) {
    memcpy(&myData, incomingData, sizeof(myData));
    Serial.println(myData.command); // Print the received command

    // Check and move the servo based on the last position
    if (lastPos == 0) {
      myServo.write(90);  // Move servo to 90 degrees
      lastPos = 90;       // Update last position
    } else {
      myServo.write(0);   // Move servo to 0 degrees
      lastPos = 0;        // Update last position
    }

    // Add a delay to allow servo movement
    delay(1000);
  } else {
    Serial.println("Error: Incorrect data length");
  }
}

void setup() {
  // Initialize Serial Monitor
  Serial.begin(115200);

  // Set device as a Wi-Fi Station
  WiFi.mode(WIFI_STA);

  // Initialize Servo
  ESP32PWM::allocateTimer(0);
  ESP32PWM::allocateTimer(1);
  ESP32PWM::allocateTimer(2);
  ESP32PWM::allocateTimer(3);
  myServo.setPeriodHertz(50);       // Standard 50 Hz for servos
  myServo.attach(SERVO_PIN, 500, 2400); // Attach the servo
  myServo.write(0);                 // Set initial position
  lastPos = 0;                      // Initialize position tracker

  // Test Servo Movement (Initial sweep from 0 to 90, then back to 0)
  for (int pos = 0; pos <= 90; pos++) {
    myServo.write(pos);
    delay(15);
  }
  for (int pos = 90; pos >= 0; pos--) {
    myServo.write(pos);
    delay(15);
  }

  // Initialize ESP-NOW
  if (esp_now_init() != ESP_OK) {
    Serial.println("Error initializing ESP-NOW");
    return;
  }

  // Register callback for received data
  esp_now_register_recv_cb(OnDataRecv);
}

void loop() {
  // Nothing is required here since everything is handled in the callback
}
pert 8

I moved your topic to a more appropriate forum category @irishknots .

The Nano ESP32 category you chose is only used for discussions directly related to the Arduino Nano ESP32 board.

In the future, please take the time to pick the forum category that best suits the subject of your question. There is an "About the _____ category" topic at the top of each category that explains its purpose.

Thanks in advance for your cooperation.

9

why not

void OnDataRecv (
    const esp_now_recv_info *recvInfo,
    const uint8_t           *incomingData,
    int                      len )
{
    if (len != sizeof(myData)) {
        Serial.println ("Error: Incorrect data length");
        return
    }

    myServo.write (*incomingData);
}