Delay only some function

Question

I have code which control thermometer, OLED and nanoservo via MQTT. I want to refresh temperature every 10s. It works but my servo receive command only when temperature is refreshed. How can I configure my loop so my servo can receive MQTT command anytime I send it?

Here in my code (I combined several example codes...):

 #include <ESP8266WiFi.h>
 #include <Servo.h>
 #include <PubSubClient.h>
 #include <OneWire.h>
 #include <DallasTemperature.h>
 #include <Wire.h>
 #include "SH1106.h"
 #include "thermometer.h"
 // Data wire is plugged into pin 2 on the Arduino
 #define ONE_WIRE_BUS 14 // je D5 was 2 (D4)
 // Setup a oneWire instance to communicate with any OneWire devices 
 // (not just Maxim/Dallas temperature ICs)
 OneWire oneWire(ONE_WIRE_BUS);
 // Pass our oneWire reference to Dallas Temperature.
 DallasTemperature sensors(&oneWire);
 SH1106 display(0x3c, D1, D2);
 #define DEMO_DURATION 3000
 typedef void (*Demo)(void);
 int demoMode = 0;
 int counter = 1;
 // Update these with values suitable for your network.
 const char* ssid = "******";
 const char* password = "******";
 const char* mqtt_server = "192.168.100.220"; /// MQTT Broker
 const char* topic_state = "/blinds/state";
 const char* topic_command = "/blinds/command";
 IPAddress my_ip (192, 168, 100, 224);
 IPAddress my_gateway (192,168, 100, 1);
 IPAddress my_subnet (255, 255, 255, 0);
 WiFiClient espClient;
 PubSubClient client(espClient);
 long lastMsg = 0;
 char msg[50];
 int value = 0;
 Servo myservo;
 int state = 0;
 int prevstate = 0;
 int dirc = 0;
 int spintime = 0;
 int servoPin = D4; //CHANGE TO WHATEVETR PIN YOUR USING
 void reconnect();
 void callback(char* topic, byte* payload, unsigned int length);
 void setup() { 
 Serial.begin(115200);
 setup_wifi();
 client.setServer(mqtt_server, 1883);
 client.setCallback(callback);
 // Start up the library
 sensors.begin();
 // Initialising the UI will init the display too.
 display.init();
 display.flipScreenVertically();
 display.setFont(ArialMT_Plain_10);
 }
 void servo_move() {
 Serial.println("State Change. Rotating Servo");
 if ( dirc == 180) {
 client.publish(topic_state,"open");
 }
 else if (dirc == 0) {
 client.publish(topic_state,"close"); 
 }
 myservo.attach(servoPin);
 myservo.write(dirc);
 delay(spintime);
 myservo.detach();
 Serial.println("Returning to main loop");
 return;
 }
 void setup_wifi() {
 delay(10);
 // We start by connecting to a WiFi network
 Serial.println();
 Serial.print("Connecting to ");
 Serial.println(ssid);
 WiFi.setPhyMode(WIFI_PHY_MODE_11N);
 WiFi.config(my_ip, my_gateway, my_subnet);
 WiFi.mode(WIFI_STA);
 WiFi.begin(ssid, password);
 while (WiFi.status() != WL_CONNECTED) {
 delay(500);
 Serial.print(".");
 }
 Serial.println("");
 Serial.println("WiFi connected");
 Serial.println("IP address: ");
 Serial.println(WiFi.localIP());
 }
 void callback(char* topic, byte* payload, unsigned int length) {
 Serial.print("Message arrived [");
 Serial.print(topic);
 Serial.print("] ");
 for (int i = 0; i < length; i++) {
 Serial.print((char)payload[i]);
 }
 Serial.println();
 char *blindcommand = (char *) payload; // convert mqtt byte array into char array
 blindcommand[length] ='0円'; // Must delimit with 0
 Serial.print(blindcommand);
 if (strcmp(blindcommand,"open") == 0) {
 Serial.println(" 433MHZ OPEN COMMAND RECEIVED");
 dirc = 180; // direction for servo to run
 spintime = 50; // << CHANGE TO WHATEVER TIME YOU NEED TO OPEN YOUR BLINDS
 state = 1; //sets current state
 }
 else if (strcmp(blindcommand,"close") == 0) {
 Serial.println(" 433MHZ CLOSE COMMAND RECEIVED");
 dirc = 0;
 spintime = 150; // << CHANGE TO WHATEVER TIME YOU NEED TO CLOSE YOUR BLINDS
 state = 2; //sets current state
 }
 if (state != prevstate) {
 Serial.println("State change!");
 servo_move();
 }
 prevstate = state;
 }
 char temperatureVonku[15];
 String tempUnit = " °C";
 void temperature(){
 float temperatureFloat;
 sensors.requestTemperatures();
 temperatureFloat = sensors.getTempCByIndex(0);
 dtostrf(temperatureFloat, 7, 1, temperatureVonku);
 client.publish("temp/outside", temperatureVonku); /// send char
 delay(10000);
 }
 void dispTempVonku() {
 display.drawRect(1, 1, DISPLAY_WIDTH -1, DISPLAY_HEIGHT -1);
 // Font Demo1
 // create more fonts at http://oleddisplay.squix.ch/
 display.setTextAlignment(TEXT_ALIGN_LEFT);
 display.setFont(Roboto_Bold_12);
 display.drawString(5, 5, "Temp: ");
 display.drawXbm(7, 24, Img_width, Img_height, thermometer);
 display.setTextAlignment(TEXT_ALIGN_CENTER);
 display.setFont(Roboto_Bold_28);
 display.drawString(64, 22, temperatureVonku + tempUnit);
 }
 void dispTempVnutri() { 
 display.drawRect(1, 1, DISPLAY_WIDTH -1, DISPLAY_HEIGHT -1);
 display.setTextAlignment(TEXT_ALIGN_CENTER);
 display.setFont(ArialMT_Plain_16);
 display.drawString(64, 22, "Hello World");
 }
 Demo demos[] = {dispTempVonku, dispTempVnutri};
 int demoLength = (sizeof(demos) / sizeof(Demo));
 long timeSinceLastModeSwitch = 0;
 void reconnect() {
 // Loop until we're reconnected
 while (!client.connected()) {
 Serial.print("Attempting MQTT connection...");
 // Attempt to connect
 if (client.connect("ESP8266Client", "******", "******")) {
 Serial.println("connected");
 client.subscribe(topic_command);
 } else {
 Serial.print("failed, rc=");
 Serial.print(client.state());
 Serial.println(" try again in 5 seconds");
 // Wait 5 seconds before retrying
 delay(5000);
 }
 }
 }
 void loop() {
 temperature(); 
 if (!client.connected()) {
 reconnect();
 }
 client.loop();
 // clear the display
 display.clear();
 // draw the current demo method
 demos[demoMode]();
 display.setTextAlignment(TEXT_ALIGN_RIGHT);
 display.drawString(10, 128, String(millis()));
 // write the buffer to the display
 display.display();
 if (millis() - timeSinceLastModeSwitch > DEMO_DURATION) {
 demoMode = (demoMode + 1) % demoLength;
 timeSinceLastModeSwitch = millis();
 }
 counter++;
 //delay(10000);
 }

Thank you.

• Sonali_B: please follow the below links, might be useful: stackoverflow.com/questions/5452394/… stackoverflow.com/questions/14397973/…
• user31481: MQTT does not guarantee delivery times. Delays between publishing and receiving can reach 2-3 seconds in a local configuration. If you are using an Internet broker, it's worse.

Answer 1

I assume your servo only receives data when you keep the delay(10000).

The problem is that with a delay, the Arduino does kind of nothing during that time, so it cannot control your servo.

What you want is to call every 10 s the temperature update, but keep the servo control always running.

So keep a last-time-called variable (type unsigned long) that keeps the time of the last call to update the temperature. When 10 s have passed (you can check somewhere in the loop), you call it, and update the last time to the current time.