At first sorry for my bad english because i am from France. I’ll do my best for explaining my problem.
I am doing a message box. in fact i send a text via Blynk app with the textIn widget and I receive it on a physical LCD and a led call me when a new message is received.
I a am using a Wemos D1 mini
it works well, very well but only if i download the code and if i use it right now.
When i unplug the power to put it on a other power source or simply switch it off and switch it on, the Wemos can’t find the wifi connection.
But if i plug it to my computer and RE-download the sketch it works (if only the wemos stay plugged)…
Could you please help me?
Thank you for all you can do for me
I send you the code if it helps you but for me its works good:
#include <LiquidCrystal_I2C.h> // bibliothèque ecran I2C
#include <Wire.h> // bibliothèque I2C
LiquidCrystal_I2C lcd(0x3F, 16, 2); // adresse I2C et type de LCD
#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#include <SimpleTimer.h> // bibliotheque du timer
char auth[] = "help"; // code du projet
char ssid[] = "help"; // nom du reseau
char pass[] = "help";// mot de passe
SimpleTimer timer; // definition nom du timer
int etatbouton = 0; // etat du bouton
bool recu = false; // booleen du message recu via l'application
void checkbouton() { // boucle du test etat bouton
etatbouton = digitalRead(D3); // lecture etat bouton
if (etatbouton == HIGH) { // si bouton appuyé
Serial.println("appui"); // ecrit dans le port serie "appui"
lcd.noBacklight(); // eteinte du fond d'ecran
lcd.noDisplay(); // et de l'ecriture
}
else { // sinon
Serial.println("pas d'appui"); //ecrit dans le port serie "pas dappui"
lcd.backlight(); // allumage fond d'ecran
lcd.display(); // et de l'ecriture
digitalWrite(D7, LOW); // eteinte de la led qui est D7
recu = false; // mise en etat Faux du message recu
}
}
void setup()
{
lcd.begin(); // initialisation lcd
lcd.backlight();// mise en marche du fond d'ecran
timer.setInterval(500, checkbouton); // declaration de l'intervalle
//du controle de l'etat du bouton ici 500ms
pinMode(D3, INPUT); // declaration du bouton en D3 il recoit l'info
pinMode(D7, OUTPUT); // declaration de la led en D7 elle envoi l'info
Serial.begin(9600);// initialisation du port serie
Blynk.begin(auth, ssid, pass); // initialisation de Blynk avec les
// identifiants
Serial.print("Blynk Ready\n"); // ecrit dans le port serie que Blynk
// est connecté une fois les etapes d'authentification validées
}
BLYNK_WRITE(V0) { // la pin virtuelle V0 ecrit:
lcd.clear();// nettoyage de l'ecran
String textIn = param.asStr(); // les parametre recus de lapp (param.Str)
// sont logés dans une ligne de lettres (string) sous le nom de TextIn
Serial.print(textIn + "\n"); // ecrit ce texte dans le port serie
char val_1[21]; // partie de code pour que selon le nombre de caractere
char val_2[21];// cela secrive sur plusieurs lignes
char val_3[21];// en fonction du type d'ecran
char val_4[21];
String row1 = textIn.substring(0, 20); // ici pour un ecran de 20x4
String row2 = textIn.substring(20, 40);
String row3 = textIn.substring(40, 60);
String row4 = textIn.substring(60, 80);
row1.toCharArray(val_1, 21);
row2.toCharArray(val_2, 21);
row3.toCharArray(val_3, 21);
row4.toCharArray(val_4, 21);
lcd.setCursor(0, 0);
lcd.print(val_1);
lcd.setCursor(0, 1);
lcd.print(val_2);
lcd.setCursor(0, 2);
lcd.print(val_3);
lcd.setCursor(0, 3);
lcd.print(val_4);
recu = true; // uen fois le texte recu, passage en etat true
}
void loop() {
Blynk.run(); // faire tourner le code prorpe a Blynk
timer.run(); // idem pour le timer
if (recu == true && etatbouton == HIGH) { // si il y a un
// message recu et que le bouton est appuyé
digitalWrite(D7, HIGH);// on fait clignoter la led intervalle de 500ms
delay(500);
digitalWrite(D7, LOW);
delay(500);
}
}```
And thanks again and again for your help with my projects.
So i modify my terrible loop just after reading the link you send me.
My wemos is connected to the USB port and my LCD directly on my wemos ( with my others projects it works).
Even with the modifications i’ve done ( for the loop) the problem is the same, it works well just after downloading the sketch but when i switch off and the on, Blynk told me “wemos is offline” and i can’t reconnect it. Unless i redownload the code and don’t unplug the wemos.
here is my modify code:
#include <LiquidCrystal_I2C.h> // bibliothèque ecran I2C
#include <Wire.h> // bibliothèque I2C
LiquidCrystal_I2C lcd(0x3F, 16, 2); // adresse I2C et type de LCD
#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#include <SimpleTimer.h> // bibliotheque du timer
char auth[] = "help"; // code du projet
char ssid[] = "help"; // nom du reseau
char pass[] = "help";// mot de passe
SimpleTimer timer; // definition nom du timer
int etatbouton = 0; // etat du bouton
bool recu = false; // booleen du message recu via l'application
void checkbouton() { // boucle du test etat bouton
etatbouton = digitalRead(D3); // lecture etat bouton
if (etatbouton == HIGH) { // si bouton appuyé
Serial.println("appui"); // ecrit dans le port serie "appui"
lcd.noBacklight(); // eteinte du fond d'ecran
lcd.noDisplay(); // et de l'ecriture
}
else { // sinon
Serial.println("pas d'appui"); //ecrit dans le port serie "pas dappui"
lcd.backlight(); // allumage fond d'ecran
lcd.display(); // et de l'ecriture
digitalWrite(D7, LOW); // eteinte de la led qui est D7
recu = false; // mise en etat Faux du message recu
}
}
void averti(){
if (recu == true && etatbouton == HIGH) { // si il y a un
// message recu et que le bouton est appuyé
digitalWrite(D7, HIGH);// on fait clignoter la led intervalle de 500ms
delay(500);
digitalWrite(D7, LOW);
delay(500);
}
}
void setup()
{
lcd.begin(); // initialisation lcd
lcd.backlight();// mise en marche du fond d'ecran
timer.setInterval(500, checkbouton); // declaration de l'intervalle
//du controle de l'etat du bouton ici 500ms
timer.setInterval(500, averti);
pinMode(D3, INPUT); // declaration du bouton en D3 il recoit l'info
pinMode(D7, OUTPUT); // declaration de la led en D7 elle envoi l'info
Serial.begin(9600);// initialisation du port serie
Blynk.begin(auth, ssid, pass); // initialisation de Blynk avec les
// identifiants
Serial.print("Blynk Ready\n"); // ecrit dans le port serie que Blynk
// est connecté une fois les etapes d'authentification validées
}
BLYNK_WRITE(V0) { // la pin virtuelle V0 ecrit:
lcd.clear();// nettoyage de l'ecran
String textIn = param.asStr(); // les parametre recus de lapp (param.Str)
// sont logés dans une ligne de lettres (string) sous le nom de TextIn
Serial.print(textIn + "\n"); // ecrit ce texte dans le port serie
char val_1[21]; // partie de code pour que selon le nombre de caractere
char val_2[21];// cela secrive sur plusieurs lignes
char val_3[21];// en fonction du type d'ecran
char val_4[21];
String row1 = textIn.substring(0, 20); // ici pour un ecran de 20x4
String row2 = textIn.substring(20, 40);
String row3 = textIn.substring(40, 60);
String row4 = textIn.substring(60, 80);
row1.toCharArray(val_1, 21);
row2.toCharArray(val_2, 21);
row3.toCharArray(val_3, 21);
row4.toCharArray(val_4, 21);
lcd.setCursor(0, 0);
lcd.print(val_1);
lcd.setCursor(0, 1);
lcd.print(val_2);
lcd.setCursor(0, 2);
lcd.print(val_3);
lcd.setCursor(0, 3);
lcd.print(val_4);
recu = true; // uen fois le texte recu, passage en etat true
}
void loop() {
Blynk.run(); // faire tourner le code prorpe a Blynk
timer.run(); // idem pour le timer
}
i tried different things when i can’t get a reconnection,
I tried the USB from my PC, a power bank and the power from my house ( i don’t how to say that in english) via the phone charger
It is the same things with de 74800 baud ( modified in sketch and serial monitor):
i tried with the ““Erase Flash - All Flash Contents”” option unfortunately i can’t again when i reboot
So do you see anything in the serial monitor (if the serial monitor is already open then close it and re-open).
Do you see anything in the serial monitor when you press the reset button?
If so, then post it here.
Hi Pete,
So i tried to put Serial.begin at the beginning of the void setup but nothing changes, i have the same message in the serial monitor.
Then i tried with 2 different simple sketches and i have the same issue. It works just after the download but if i switch off and then on, i can’t reconnect it to the wifi.
But what is strange is that before with a simple sketch project i could switch off and on for replugging it on a other power source i had no problem
That looks fine.
You could check your board for solder bridges between pins, or splatter that’s caused small blobs of solder to short-out components, but otherwise you may need a new board.
It’s very rare for these boards top develop a problem. I have around 40 of them and I’ve only experienced one that developed a problem. You should obviously take normal anti-static precautions when handling them, and avoid applying 5v to the 3.3v pin.
The problem was the same, but i tried something different, I disconnected power of the display, then i plug the power of the wemos, i wait and he find the wifi connection.
Then i re-plugged the power of the display , the wemos stay connected but the display don’t works well (it is only full squares on the screen ).
So i looked at the serial monitor and i saw that :
"[82424] Heartbeat timeout
appui
appui
appui
appui
appui
[87393] Connecting to blynk-cloud.com:80
[87457] Ready (ping: 30ms).
appui
appui
"
I’d previously asked you to disconnect everything from the Wemos. I thought that the tests you were doing after that were with just the Wemos board and nothing else!
