I have esp8266, it connected to 3 temperature sensors. I put all data in list (temperature and time). After 9 hour of work esp8266 just refresh everything and all data get lost. I tried check my code, but problem still there.
I expected that it will just edit previous temperatures and it will not reset. Here is schema (without 8266): Schema without esp8266
Here is my code:
#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>
#include <OneWire.h>
#include <DallasTemperature.h>
#include <WiFiUdp.h>
#include <EEPROM.h>
#define SENSORS_PIN D7
OneWire oneWire1(SENSORS_PIN);
DallasTemperature sensors(&oneWire1);
const int numSensors = 3;
const int maxRecords = numSensors * 1000;
const int INTERVAL_ADDRESS_IN_EEPROM = 0;
float temperatures[maxRecords];
unsigned long timestamps[maxRecords];
int ids[maxRecords];
int dataIndex = 0;
unsigned long lastMillis = 0;
int interval = 10000;
unsigned long blink = 0;
int blink_type = 0;
const char* ssid = "MY-SSID";
const char* password = "MY-PASSWORD";
ESP8266WebServer server(80);
WiFiUDP udp;
const unsigned int udpPort = 4210;
unsigned long lastUdpMillis = 0;
int sensor_ids[numSensors] = {1,2,3};
void writeToEEPROM(int address, int value) {
EEPROM.put(address, value);
EEPROM.commit();
}
int readFromEEPROM(int address) {
int value;
EEPROM.get(address, value);
return value;
}
void setup() {
pinMode(SENSORS_PIN, INPUT_PULLUP);
pinMode(LED_BUILTIN, OUTPUT);
sensors.begin();
Serial.begin(9600);
EEPROM.begin(512);
interval = readFromEEPROM(INTERVAL_ADDRESS_IN_EEPROM);
if (interval <= 0 || interval > 60000) {
interval = 10000;
writeToEEPROM(INTERVAL_ADDRESS_IN_EEPROM, interval);
Serial.println("Interval set to default value: 10000 milliseconds");
} else {
Serial.printf("Current interval is %d milliseconds\n", interval);
}
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("\nConnected to WiFi");
Serial.print("IP Address: ");
Serial.println(WiFi.localIP());
udp.begin(udpPort);
server.on("/status", []() {
server.send(200, "text/html", "OK");
});
server.on("/setinterval", []() {
int newInterval = server.arg("interval").toInt();
if (newInterval > 0 && newInterval <= 60000) {
interval = newInterval;
writeToEEPROM(INTERVAL_ADDRESS_IN_EEPROM, interval);
Serial.printf("Interval updated to %d milliseconds\n", interval);
server.send(200, "text/html", "<p>Interval set</p>");
} else {
server.send(400, "text/html", "<p>Invalid interval</p>");
}
});
server.on("/exit", []() {
Serial.println("Restarting device...");
server.send(200, "text/html", "Exiting");
ESP.restart();
});
server.on("/temp", []() {
String sensor_id = server.arg("sensor_id");
int limit = server.arg("limit").toInt();
unsigned long currentMillis = millis();
unsigned long time_frame = 0;
bool filterByTime = server.hasArg("time");
unsigned long requestTime = server.arg("time").toInt() * 1000;
if (filterByTime) {
time_frame = currentMillis - requestTime;
} else {
time_frame = 0;
}
if (limit <= 0) {
limit = 10;
}
String response = "{\"temperature_data\":[";
int count = 0;
int totalMatched = 0;
for (int i = 0; i < maxRecords; i++) {
bool isWithinTimeFrame = !filterByTime || timestamps[i] >= time_frame;
bool matchesSensorId = sensor_id.isEmpty() || ids[i] == sensor_id.toInt();
if (ids[i] != 0 && isWithinTimeFrame && matchesSensorId) {
totalMatched++;
if (count < limit) {
if (count > 0) {
response += ",";
}
response += "{\"temp\":" + String(temperatures[i], 2) + ",\"time\":" + String(currentMillis - timestamps[i]) + ",\"sensor_id\":" + ids[i] + "}";
count++;
}
}
}
int remainCount = totalMatched - count;
response += "],\"remain_cnt\":" + String(remainCount) + "}";
server.send(200, "application/json", response);
});
Serial.println("Server started");
server.begin();
}
void loop() {
server.handleClient();
if (millis() - blink >= 100) {
blink = millis();
if (blink_type == 1) {
digitalWrite(LED_BUILTIN, HIGH);
blink_type = 0;
}else{
digitalWrite(LED_BUILTIN, LOW);
blink_type = 1;
}
}
if (millis() - lastMillis >= interval) {
lastMillis = millis();
for (int i = 0; i < numSensors; i++) {
sensors.requestTemperatures();
float temperature = sensors.getTempCByIndex(i);
int lastIndex = (dataIndex - 1 + maxRecords) % maxRecords;
int secondLastIndex = (dataIndex - 2 + maxRecords) % maxRecords;
float lastTemperature = temperatures[lastIndex];
float secondLastTemperature = temperatures[secondLastIndex];
float diffLast = abs(temperature - lastTemperature);
float diffSecondLast = abs(temperature - secondLastTemperature);
if (diffLast <= 0.2 && diffSecondLast <= 0.2) {
timestamps[lastIndex] = millis();
} else {
temperatures[dataIndex] = temperature;
timestamps[dataIndex] = millis();
ids[dataIndex] = sensor_ids[i];
dataIndex = (dataIndex + 1) % maxRecords;
}
}
}
if (millis() - lastUdpMillis > 1000) {
int packetSize = udp.parsePacket();
if (packetSize) {
char packetBuffer[255];
int len = udp.read(packetBuffer, sizeof(packetBuffer) - 1);
packetBuffer[len] = '\0';
if (len > 0) {
String packetString = String(packetBuffer);
if (packetString.indexOf("DISCOVER") >= 0) {
if (packetString.indexOf(WiFi.localIP().toString()) < 0) {
IPAddress remoteIp = udp.remoteIP();
Serial.print("Device with IP: ");
Serial.print(remoteIp);
Serial.print(" is attempting to connect...");
udp.beginPacket(remoteIp, udpPort);
String message = "'DEVICE' ," + String(numSensors) + ", [";
for (int i = 0; i < numSensors; i++) {
message += sensor_ids[i];
if (i < numSensors - 1) message += ", ";
}
message += "]";
udp.print(message);
udp.endPacket();
Serial.println("Response packet sent");
}
}
} else {
Serial.println("Error reading UDP packet");
}
}
lastUdpMillis = millis();
}
}
```
the problem in this case is hard to reach as Arduino runs above the Espressif SDK and this also not bug free!
and problems with firmware that happens with time is probably from the RAM as you have nearly 40K of RAM remaining for usage.
1- better way to know if that is from your code or not is to keep the ESP connected to serial and increase debugging messages and check the serial when the bug happens again and use ESP.getFreeHeap(); to track if memory usage is growing.
2- Consider using char[] arrays instead of String objects for web responses to avoid dynamic memory allocation as much as possible.