ConsentiumNow Library API

The ConsentiumNow library simplifies the implementation of ESP-NOW communication for ESP32 devices. It provides a templated, type-safe interface for transmitting and receiving structured data between devices.

---

Class: ConsentiumNow

The ConsentiumNow class is a templated class designed to handle communication using ESP-NOW. DataType is a user-defined struct or class representing the data to be exchanged.

Template Parameter

• DataType: A user-defined data structure (e.g., a struct) that represents the data to be sent/received. Must be serializable (e.g., no pointers or virtual members).

---

Public Methods

Constructor

ConsentiumNow();

Initializes the ConsentiumNow object. Does not perform any hardware initialization.

---

void receiveBegin()

Initializes ESP-NOW in receive mode.

• Purpose: Sets up the ESP32 to receive data over ESP-NOW and register a callback function to handle incoming messages.

• Usage:

  consentiumNowInstance.receiveBegin();

• Output: Prints initialization status to Serial.

---

*void sendBegin(const uint8_t peerMac)

Initializes ESP-NOW in send mode and sets the receiver’s MAC address.

• Parameters:

  • peerMac: A 6-byte array representing the receiver's MAC address.

• Usage:

  uint8_t receiverMac[] = {0x24, 0x6F, 0x28, 0x11, 0x22, 0x33};
  consentiumNowInstance.sendBegin(receiverMac);

• Output: Prints initialization status to Serial.

---

*bool addPeer(const uint8_t peerMac)

Adds a peer (sender or receiver) to the ESP-NOW network.

• Parameters:

  • peerMac: A 6-byte array representing the MAC address of the peer to be added.

• Returns:

  • true if the peer is added successfully.

  • false if the operation fails.

• Usage:

  uint8_t senderMac[] = {0x24, 0x6F, 0x28, 0xAA, 0xBB, 0xCC};
  bool success = consentiumNowInstance.addPeer(senderMac);

• Output: Prints success/failure status to Serial.

---

void sendData(const DataType &data)

Sends data to the predefined receiver.

• Parameters:

  • data: A reference to the DataType object containing the data to be sent.

• Usage:

  SensorData sensorData = {25.5, 60.0};
  consentiumNowInstance.sendData(sensorData);

• Output:

  • Prints success/failure status to Serial.

---

bool isDataAvailable()

Checks if new data has been received.

• Returns:

  • true if new data is available.

  • false if no data is available.

• Usage:

  if (consentiumNowInstance.isDataAvailable()) {
      // Handle received data
  }

---

DataType getReceivedData()

Retrieves the most recently received data.

• Returns:

  • The received data of type DataType.

• Usage:

  SensorData receivedData = consentiumNowInstance.getReceivedData();
  Serial.printf("Temperature: %.2f, Humidity: %.2f\n", 
                receivedData.temperature, receivedData.humidity);

• Note: Resets the data availability flag.

---

void readMacAddress()

Prints the MAC address of the ESP32 to the Serial monitor.

• Purpose: Useful for identifying devices in an ESP-NOW network.

• Usage:

  consentiumNowInstance.readMacAddress();

---

Static Callback Methods

void onDataReceive(const esp_now_recv_info_t info, const uint8_t incoming, int len)

Handles incoming ESP-NOW messages. Automatically called when data is received.

• Parameters:

  • info: Information about the sender (e.g., MAC address).

  • incoming: Pointer to the incoming data.

  • len: Length of the received data.

• Purpose: Parses and stores incoming data in the incomingData buffer and sets the dataAvailable flag.

• Usage: Registered automatically by receiveBegin().

---

Static Variables

DataType incomingData

Holds the latest received data.

• Scope: Private (access via getReceivedData()).

---

bool dataAvailable

Indicates whether new data has been received.

• Scope: Private (access via isDataAvailable()).

---

Example: Using ConsentiumNow

Receiver Code

#include "ConsentiumNow.h"

struct SensorData {
    float temperature;
    float humidity;
};

ConsentiumNow<SensorData> receiver;

void setup() {
    Serial.begin(115200);
    receiver.receiveBegin();
}

void loop() {
    if (receiver.isDataAvailable()) {
        SensorData data = receiver.getReceivedData();
        Serial.printf("Temperature: %.2f, Humidity: %.2f\n", 
                      data.temperature, data.humidity);
    }
}

Sender Code

#include "ConsentiumNow.h"

struct SensorData {
    float temperature;
    float humidity;
};

ConsentiumNow<SensorData> sender;

uint8_t receiverMac[] = {0x24, 0x6F, 0x28, 0x11, 0x22, 0x33};

void setup() {
    Serial.begin(115200);
    sender.sendBegin(receiverMac);
}

void loop() {
    SensorData data = {random(200, 300) / 10.0, random(400, 600) / 10.0};
    sender.sendData(data);
    delay(2000);
}

---

Features

• Templated Design: Flexibility to handle any structured data.

• Static Methods: Callback management for receiving data.

• Ease of Use: Abstracts ESP-NOW complexity, focusing on data exchange.

---

Known Limitations

1. Peer Management: Must manually add peers to the network using addPeer().

2. Static Data Buffer: Only one instance of incoming data can be stored.