Sending data over ESP_NOW - arduino

Question

I'm a total noob and just starting out with PlatformIO and Arduino/ESP32. I also want to say thanks in advance to any help I can get.
Plan:
I have 2 ESP32's talking over ESP_NOW, I just can't verify the data being sent in order to progress with my project. Basically, I have a Nextion display that sends specific info to an ESP32 (tested and working) and that ESP32 is then to send that information via ESP_NOW to the other ESP32 which will translate it into serial data to send to an Arduino Due and perform some tasks.
Problem:
The issue I have is that when I test, I see the data I think I am transmitting, but when I try to Serial.print said info, I get "0 0 0 0". I'm not sure that I am sending OR receiving the data properly. All I know is that when I press the button on the Nextion, I get a response on the ESP32 that is not connected.
Code:
#include <Arduino.h>
#include <esp_now.h>
#include <WiFi.h>
// Example to receive data with a start marker and length byte
// For ease of testing this uses upper-case characters A and B
// for the request and response types
// and Z for the start marker
// this version saves all the bytes after the start marker
// if the TYPE byte is wrong it aborts
const byte numBytes = 32;
byte receivedBytes[numBytes];
const byte typeBytePosition = 6; // Position after the start byte
const byte requestType = 0x65;
const byte requestLength = 7;
boolean newData = false;
int LED = 21;
// REPLACE WITH THE MAC Address of your receiver
uint8_t broadcastAddress[] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
// Define variables to store Nextion readings to be sent
byte NexEventID;
byte NexPageID;
byte NexObjectID;
byte NexStatusID;
// Define variables to store incoming readings// Define variables to store incoming readings
byte incomingEventID;
byte incomingPageID;
byte incomingObjectID;
byte incomingStatusID;
// Variable to store if sending data was successful
String success;
typedef struct struct_message
{
byte EventID;
byte PageID;
byte ObjectID;
byte StatusID;
} struct_message;
// Create a struct_message called NextionInfo to hold Nextion settings
struct_message NextionInfo;
// Create a struct_message called IncomingInfo to hold incoming info
struct_message IncomingInfo;
// Callback when data is sent
void OnDataSent(const uint8_t *mac_addr, esp_now_send_status_t status)
{
Serial.print("\r\nLast Packet Send Status:\t");
Serial.println(status == ESP_NOW_SEND_SUCCESS ? "Delivery Success" : "Delivery Fail");
if (status == 0)
{
success = "Delivery Success :)";
}
else
{
success = "Delivery Fail :(";
}
}
// Callback when data is received
void OnDataRecv(const uint8_t *mac, const uint8_t *incomingData, int len)
{
struct_message *IncomingInfo = (struct_message *)incomingData;
Serial.println(WiFi.macAddress());
// memcpy(&IncomingInfo, incomingData, sizeof(IncomingInfo));
Serial.print("Bytes received: ");
Serial.println(len);
// incomingEventID = IncomingInfo.EventID;
Serial.print((byte)IncomingInfo->EventID, HEX);
Serial.print(' ');
// incomingPageID = IncomingInfo.PageID;
Serial.print((byte)IncomingInfo->PageID, HEX);
Serial.print(' ');
// incomingObjectID = IncomingInfo.ObjectID;
Serial.print((byte)IncomingInfo->ObjectID, HEX);
Serial.print(' ');
// incomingStatusID = IncomingInfo.StatusID;
Serial.println((byte)IncomingInfo->StatusID, HEX);
}
void emptyBuffer()
{
for (byte n = 0; n < numBytes; n++)
{
receivedBytes[n] = 0;
}
}
void recvBytesWithStartMarker()
{
static boolean recvInProgress = false;
static int ndx = -1;
static byte numBytesReceived = 0;
static byte mesgLen = 0;
const byte startMarker = 0x65;
byte rc;
while (Serial2.available() > 0 && newData == false)
{
rc = Serial2.read();
receivedBytes[numBytesReceived] = rc;
numBytesReceived++;
if (numBytesReceived > 33)
{
Serial.println("Error Rx : RESET !!");
Serial.println();
emptyBuffer();
numBytesReceived = 0;
newData = false;
}
if (recvInProgress == true)
{
if (numBytesReceived == typeBytePosition)
{
ndx = 0; // enable saving of data (anticipate good data)
if (rc == requestType)
{
mesgLen = requestLength;
}
else
{
recvInProgress = false; // abort - invalid request type
ndx = -1;
}
}
if (ndx >= 0)
{
ndx++;
}
if (numBytesReceived >= (mesgLen + typeBytePosition))
{ // got the whole message
recvInProgress = false;
newData = true;
}
}
else if (rc == startMarker)
{
emptyBuffer();
recvInProgress = true;
numBytesReceived = 0;
ndx = -1; // prevent counting valid bytes for the moment
}
}
}
// void getNexInfo()
// {
// NexEventID = receivedBytes[0];
// NexPageID = receivedBytes[1];
// NexObjectID = receivedBytes[2];
// NexStatusID = receivedBytes[3];
// // Serial.print(NexEventID&&NexPageID&&NexObjectID&&NexStatusID);
// }
void showNewData()
{
if (newData == true)
{
Serial.println(WiFi.macAddress());
Serial.print(requestType, HEX);
Serial.print(' ');
for (byte n = 0; n < typeBytePosition; n++) // n < numBytes
{
if (n == 0)
{
NexEventID = receivedBytes[n];
}
else if (n == 1)
{
NexPageID = receivedBytes[n];
}
else if (n == 2)
{
NexObjectID = receivedBytes[n];
}
else if (n == 3)
{
NexStatusID = receivedBytes[n];
}
Serial.print(receivedBytes[n], HEX);
Serial.print(' ');
}
//Serial.print(getNexInfo(),HEX);
Serial.println();
// Send message via ESP-NOW
esp_err_t result = esp_now_send(broadcastAddress, (uint8_t *)&NextionInfo, sizeof(NextionInfo));
if (result == ESP_OK)
{
Serial.println("Sent with success");
}
else
{
Serial.println("Error sending the data");
}
newData = false;
}
}
void sendNewData()
{
// Set values to send
NextionInfo.EventID = NexEventID;
NextionInfo.PageID = NexPageID;
NextionInfo.ObjectID = NexObjectID;
NextionInfo.StatusID = NexStatusID;
// Send message via ESP-NOW
esp_err_t result = esp_now_send(broadcastAddress, (uint8_t *)&NextionInfo, sizeof(NextionInfo));
if (result == ESP_OK)
{
Serial.println("Sent with success");
}
else
{
Serial.println("Error sending the data");
}
}
void setup()
{
pinMode(LED, OUTPUT);
Serial.begin(250000);
Serial2.begin(115200);
while (!Serial)
{
;
}
// Set device as a Wi-Fi Station
WiFi.mode(WIFI_STA);
// 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 Send CB to
// get the status of Trasnmitted packet
esp_now_register_send_cb(OnDataSent);
// Register peer
esp_now_peer_info_t peerInfo;
memcpy(peerInfo.peer_addr, broadcastAddress, 6);
peerInfo.channel = 0;
peerInfo.encrypt = false;
// Add peer
if (esp_now_add_peer(&peerInfo) != ESP_OK)
{
Serial.println("Failed to add peer");
return;
}
// Register for a callback function that will be called when data is received
esp_now_register_recv_cb(OnDataRecv);
//Setup has completed
Serial.println("<ESP32 is ready>");
}
void loop()
{
recvBytesWithStartMarker();
showNewData();
}
Most of this has come from various tutorials across the web including YouTube and RandomNerdTutorials. I am by no means a master programmer, but I am trying to learn.
Here are the results I get from the serial monitors:
ESP32 1:
�<ESP32 is ready>
AC:67:B2:36:AA:A8
65 1 2 1 FF FF FF
Sent with success
Last Packet Send Status: Delivery Success
ESP32 2:
AC:67:B2:35:19:D8
Bytes received: 4
0 0 0 0
Note that I am only sending 4 bytes of info (65 1 2 1), so it seems to match up (I'm not sending FF FF FF)...
Thanks again for any help!!

Answer 1

I was able to resolve my issue. Below is the code that displayed the same information that was sent from the host and received by the slave ESP32.
#include <Arduino.h>
#include <esp_now.h>
#include <WiFi.h>
// Example to receive data with a start marker and length byte
// For ease of testing this uses upper-case characters A and B
// for the request and response types
// and Z for the start marker
// this version saves all the bytes after the start marker
// if the TYPE byte is wrong it aborts
const byte numBytes = 32;
byte receivedBytes[numBytes];
const byte typeBytePosition = 6; // Position after the start byte
const byte requestType = 0x65;
const byte requestLength = 7;
boolean newData = false;
int LED = 2;
// REPLACE WITH THE MAC Address of your receiver
uint8_t broadcastAddress[] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
// Variable to store if sending data was successful
String success;
struct __attribute__((packed)) dataPacket
{
byte EventID;
byte PageID;
byte ObjectID;
byte StatusID;
} packet, *packetPtr;
const dataPacket onLoc1R = {0x65, 0x01, 0x01, 0x01};
const dataPacket offLoc1R = {0x065, 0x01, 0x01, 0x00};
const dataPacket onLoc1L = {0x65, 0x01, 0x02, 0x01};
const dataPacket offLoc1L = {0x65, 0x01, 0x02, 0x00};
// Callback when data is sent
void OnDataSent(const uint8_t *mac_addr, esp_now_send_status_t status)
{
Serial.print("\r\nLast Packet Send Status:\t");
Serial.println(status == ESP_NOW_SEND_SUCCESS ? "Delivery Success" : "Delivery Fail");
}
void emptyBuffer()
{
for (byte n = 0; n < numBytes; n++)
{
receivedBytes[n] = 0;
}
}
void recvBytesWithStartMarker()
{
static boolean recvInProgress = false;
static int ndx = -1;
static byte numBytesReceived = 0;
static byte mesgLen = 0;
const byte startMarker = 0x65;
byte rc;
while (Serial2.available() > 0 && newData == false)
{
rc = Serial2.read();
receivedBytes[numBytesReceived] = rc;
numBytesReceived++;
if (numBytesReceived > 33)
{
Serial.println("Error Rx : RESET !!");
Serial.println();
emptyBuffer();
numBytesReceived = 0;
newData = false;
}
if (recvInProgress == true)
{
if (numBytesReceived == typeBytePosition)
{
ndx = 0; // enable saving of data (anticipate good data)
if (rc == requestType)
{
mesgLen = requestLength;
}
else
{
recvInProgress = false; // abort - invalid request type
ndx = -1;
}
}
if (ndx >= 0)
{
ndx++;
}
if (numBytesReceived >= (mesgLen + typeBytePosition))
{ // got the whole message
recvInProgress = false;
newData = true;
}
}
else if (rc == startMarker)
{
emptyBuffer();
recvInProgress = true;
numBytesReceived = 0;
ndx = -1; // prevent counting valid bytes for the moment
}
}
}
void showNewData()
{
if (newData == true)
{
Serial.println(WiFi.macAddress());
Serial.print(requestType, HEX);
packet.EventID = requestType;
Serial.print(' ');
for (byte n = 0; n < typeBytePosition; n++) // n < numBytes
{
if (n == 0)
{
packet.PageID = receivedBytes[n];
}
else if (n == 1)
{
packet.ObjectID = receivedBytes[n];
}
else if (n == 2)
{
packet.StatusID = receivedBytes[n];
}
Serial.print(receivedBytes[n], HEX);
Serial.print(' ');
}
Serial.println();
// Send message via ESP-NOW
esp_err_t result = esp_now_send(broadcastAddress, (uint8_t *) &packet, sizeof(packet));
if (result == ESP_OK)
{
Serial.println("Sent with success");
}
else
{
Serial.println("Error sending the data");
}
newData = false;
}
}
// Callback when data is received
void OnDataRecv(const uint8_t *mac, const uint8_t *data, int len)
{
Serial.println(WiFi.macAddress());
memcpy(&packet, data, sizeof(packet));
Serial.printf("%x %x %x %x\n",(byte) packet.EventID,(byte) packet.PageID,(byte) packet.ObjectID,(byte) packet.StatusID);
Serial.println();
}
void sendNewData()
{
// Send message via ESP-NOW
esp_err_t result = esp_now_send(broadcastAddress, (uint8_t *) &packet, sizeof(packet));
if (result == ESP_OK)
{
Serial.println("Sent with success");
}
else
{
Serial.println("Error sending the data");
}
}
void setup()
{
pinMode(LED, OUTPUT);
Serial.begin(250000);
Serial2.begin(115200);
while (!Serial)
{
;
}
// Set device as a Wi-Fi Station
WiFi.mode(WIFI_STA);
// 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 Send CB to get the status of Trasnmitted packet
esp_now_register_send_cb(OnDataSent);
// Register peer
esp_now_peer_info_t peerInfo;
memcpy(peerInfo.peer_addr, broadcastAddress, 6);
peerInfo.channel = 0;
peerInfo.encrypt = false;
// Add peer
if (esp_now_add_peer(&peerInfo) != ESP_OK)
{
Serial.println("Failed to add peer");
return;
}
// Register for a callback function that will be called when data is received
esp_now_register_recv_cb(OnDataRecv);
//Setup has completed
Serial.println("<ESP32 is ready>");
}
void loop()
{
recvBytesWithStartMarker();
showNewData();
}