@xfpd Hi xfpd,
I´ve tried it with an ESP32 and the gsm shield seems to work normal. The netlight blinks every 3 seconds but I don´t recieve anything. Not even OK.
This is an image of the esp32 connection to reduce the voltage the gnd is connected with a 270 Ohms resistor and the tx/rx with a 470 Ohms connected to the pin. So I´ll get 5Vx470/(470+220) = +- 3.17V.
@xfpd Hi xfpd, he´s working now. I used other Gpio´s and another sketch. I´ll put it later here with the wiring. I´m going to use it as an alarm which sends an sms when the power falls out.
Thank you for the interest and your time.
Greetings Rudy.
@xfpd Like I said this is the sketch that's working for me.
#include <SoftwareSerial.h>
// Wiring
/*
* GSM shield Arduino RY1:5V RY2 T1:NPN
* 5V VINN 5V COM
* GND GND T1:E GND B
* 12V 12V
* J1 7
* J2 8
* 11 11 NC
* 13 C
* PWRKey COM
* PWRKey NO
* 2V8 A5
* 11 A3
*
*/
//Create software serial object to communicate with SIM900
SoftwareSerial GSM900(7, 8); //SIM900 Tx & Rx is connected to Arduino #7 & #8
char incoming_char = 0;
int pinStartUp = 13; // Used to start up the GSM shield
int pinIn = 11; // controlates if there's still power on the relay
int analogPin = A3; // from RY2 NO
int valA = 0; // variables to store the readed value
int valB = 0;
int val = 0; // integer to read digital value, comes from relay NC
int powerPin = A5; // analog pin5 used to measure if the module is powered and needs a restart from 2V8 gsm-shield
int smsVal = 0;
int counter = 0;
int count = 0;
void setup() {
pinMode(pinIn, INPUT);
pinMode(pinStartUp, OUTPUT);
//Begin serial communication with Arduino and Arduino IDE (Serial Monitor)
Serial.begin(19200);
Serial.println("Initializing...");
//Begin serial communication with Arduino and SIM900
GSM900.begin(19200);
}
void loop() {
val = digitalRead(pinIn);
valA = analogRead(analogPin); // read the input pin
valB = analogRead(powerPin);
if (val == 1 ) {
resetCounter();
} else if (val != 1 && counter >= 49 && smsVal < 2 && valA < 1000) {
if (smsVal < 1) {
// An error occured, send sms
sendSms();
delay(1000);
Serial.println("Sending sms....");
}
} else {
}
if (valB < 100) {
count++;
if (count >= 15) {
/*Serial.print("Count = ");
Serial.println(count);
Serial.println(valB);*/
startUp();
}
}
updateSerial();
if (valA == 0 && counter < 50) {
counter += 1;
}
delay(1000);
if (counter != 0) {
Serial.print("Counter = ");
Serial.println(counter);
}
}
void updateSerial() {
delay(500);
while (Serial.available()) {
GSM900.write(Serial.read()); //Forward what Serial received to Software Serial Port
}
}
void sendSms() {
smsVal++;
delay(100);
GSM900.println("AT"); //Once the handshake test is successful, it will back to OK
updateSerial();
GSM900.println("AT+CMGF=1"); // Configuring TEXT mode
updateSerial();
GSM900.println("AT+CMGS=\"+ZZxxxxxxxxx\""); //change ZZ with country code and xxxxxxxxxxx with phone number to sms
updateSerial();
GSM900.print("Power failer"); //text content
updateSerial();
GSM900.write(26);
}
void startSystem() {
// Give the module the time to start up and start reading from input
delay(2000);
counter += 1;
}
void resetCounter() {
// Serial.println("Reset counter");
counter = 0;
if (smsVal > 0) {
smsVal = 0;
}
}
void startUp() {
digitalWrite(pinStartUp, HIGH);
Serial.println("Start up");
delay(2000);
digitalWrite(pinStartUp, LOW);
Serial.println("Done starting up");
count = 0;
}
@xfpd Wiring and also the power supply. I used in first case rx and tx from the UNO, now I'm using 7 and 8. At this moment I'm only sending messages, later I like to receive messages also, but at this moment I don't need it.
