How to get live GPS Sim800 Module RTC time on Arduino

Question

Hello I wanted the live GPS Sim800 Module RTC time on Arduino without the use of library, I am able to achieve it using library but without library the correct data comes in only 1 minute and other comes the garbage.

Please tell me the code that can help me achieve it

Using code I did the following thing

#include <SoftwareSerial.h>
SoftwareSerial gsm(10, 11);
String Buffer;
String inData;

int i;
int *year, *month, *day, *hour, *minute, *second;

void setup() {
  Serial.begin(9600);
  gsm.begin(9600);
  delay(5000);
}

void loop() {
Ansh:
  delay(500);
  gsm.println("AT+CCLK?\r\n");
  while (gsm.available()) {
    char recieved = gsm.read();
    inData += recieved;
    delay(100);

    // Process message when new line character is recieved
    if (recieved == '\n')
    {
      Serial.print("Arduino Received: ");
      Serial.println(inData);

      if (inData.substring(1, 5) == "+CCLK") {
        Serial.println("Hello");
      }

      // You can put some if and else here to process the message juste like that:

      if (inData == "+++\n") { // DON'T forget to add "\n" at the end of the string.
        Serial.println("OK. Press h for help.");
      }


      inData = ""; // Clear recieved buffer
      goto Ansh;
    }

    /* Buffer = Buffer.substring(Buffer.indexOf("\"") + 1, Buffer.lastIndexOf("\"") - 1);
      year = Buffer.substring(0, 2).toInt();
      month = Buffer.substring(3, 5).toInt();
      day = Buffer.substring(6, 8).toInt();
      hour = Buffer.substring(9, 11).toInt();
      minute = Buffer.substring(15, 17).toInt();
      second = Buffer.substring(18, 20).toInt();
    */
  }/*
  Serial.println(*hour);
  delay(100);
  Serial.println(*minute);
  delay(100);
  Serial.println(*second);
  delay(100);
*/
}

But I don't get live output but after 1 correct output it returns garbage as follows

12:22:38.960 -> Arduino Received: +CCLK: "20/10/04,12:22:31+22" 12:22:38.960 -> 12:22:39.672 -> Arduino Received: 12:22:39.672 -> 12:22:40.596 -> Arduino Received: OK 12:22:40.596 -> 12:22:42.339 -> Arduino Received: AT+CCLK?

12:22:42.339 -> 12:22:44.362 -> Arduino Received: +CCAT+CCLK?

12:22:44.362 -> 12:22:46.067 -> Arduino Received: AT+CCLK?

12:22:46.067 -> 12:22:50.344 -> Arduino Received: +CCLK: "20/10/04,12ATAT+CAT+CCLK?

12:22:50.344 -> 12:22:52.043 -> Arduino Received: AT+CCLK?

12:22:52.043 -> 12:22:54.082 -> Arduino Received: +CCAT+CCLK?

12:22:54.082 -> 12:22:55.822 -> Arduino Received: AT+CCLK?

12:22:55.822 -> 12:23:00.064 -> Arduino Received: +CCLK: "20/10/04,12:22:49AT+CCLK?

12:23:00.098 -> 12:23:01.791 -> Arduino Received: AT+CCLK?

12:23:01.791 -> 12:23:03.810 -> Arduino Received: +CCAT+CCLK?

12:23:03.845 -> 12:23:05.552 -> Arduino Received: AT+CCLK?

12:23:05.552 -> 12:23:09.803 -> Arduino Received: +CCLK: "20/10/04,12:22:58AT+CCLK?

12:23:09.838 -> 12:23:11.544 -> Arduino Received: AT+CCLK?

12:23:11.544 -> 12:23:13.563 -> Arduino Received: +CCAT+CCLK?

12:23:13.563 -> 12:23:15.290 -> Arduino Received: AT+CCLK?

12:23:15.290 -> 12:23:19.557 -> Arduino Received: +CCLK: "20/10/04,12:23:08AT+CCLK?

12:23:19.557 -> 12:23:21.278 -> Arduino Received: AT+CCLK?

if I remove the delays from the code then I receive the following output

12:34:56.406 -> Arduino Received: (⸮⸮SCC⸮⸮CL?⸮

1-⸮

AT+CCLK?

AT+CCL~Q⸮ -j 12:34:56.473 -> 12:34:56.541 -> Arduino Received: ⸮5⸮⸮AT+CCLK?

⸮⸮⸮~⸮⸮ 1⸮j⸮b-⸮

AT+CCLK?

AT+C⸮~⸮⸮ 1-j⸮5⸮⸮(⸮i 1-⸮

AV⸮1-j 12:34:56.607 -> 12:34:56.913 -> Arduino Received: ⸮5⸮⸮J⸮jj⸮j AT+CCLK?

AT+CCLK?

AT+CCLK?

AT+CK5Q⸮ 1⸮j⸮5⸮⸮AT+CCLK?

AT+CCLK?

AT+CCLK?

AT+CCLK?

AT+CCLK?

AT+CCLK⸮Q⸮ Zj⸮5⸮⸮(⸮⸮1-⸮

⸮

1⸮j⸮5j⸮ը(⸮CCP⸮i 1-⸮5Q⸮⸮j⸮jj⸮ը(j⸮jQb⸮⸮E⸮jj⸮(⸮⸮1-⸮5Q⸮ Zj⸮5⸮⸮(⸮⸮(j⸮jQ⸮Zj⸮5j⸮ը(⸮j⸮⸮ 1⸮j⸮⸮5j⸮(⸮⸮(⸮j⸮V 1-j 12:34:57.184 -> 12:34:57.252 -> Arduino Received: ⸮5⸮⸮D⸮j1-⸮

AT+CCLK?

AT+CCLK?

AT+CCLK?

AT+CCLK?

AT+CCLK?

A 1-⸮

AT+CCLK?

AT+CCLK?

AT+CCLK?

AT+CCL~Q⸮ -j 12:34:57.354 -> 12:34:57.561 -> Arduino Received: ⸮5⸮⸮AT+CCLK?

AT+CCLK?

AT+CCLK?

AT+CCLK?

AT+CCLK?

AT+CCLK? j AT+CCLK?

AT+CCLK?

AT+CCLK?

AT+CCLK?

AT+C⸮⸮5Q⸮⸮⸮Ԋi⸮j⸮(Q⸮⸮j⸮jj⸮ը(⸮CCP⸮i⸮j⸮ը(⸮CC⸮⸮⸮K? ⸮+CCLK?

AT+C⸮Q⸮Zj⸮5⸮⸮(Q⸮ -j 12:34:57.763 -> 12:34:57.763 -> Arduino Received: ⸮5⸮⸮E⸮jj⸮j AT+CCLK?

AT+CCLK?

AT+CCLK?

AT+CCLK?

AT+CCLK?

AT⸮⸮z⸮⸮z⸮⸮b⸮⸮Қ⸮Ҫ⸮Z⸮⸮j 12:34:57.866 -> 12:34:57.866 -> Arduino Received: 12:34:57.905 -> 12:34:57.905 -> Arduino Received: OK 12:34:57.968 -> 12:34:57.968 -> Arduino Received: AT+CCLK?

12:34:57.968 -> 12:34:57.968 -> Arduino Received: +CCLK: "20/10/04,12:34:54+22" 12:34:58.037 -> 12:34:58.037 -> Arduino Received: 12:34:58.070 -> 12:34:58.070 -> Arduino Received: OK 12:34:58.070 -> 12:34:58.070 -> Arduino Received: AT+CCK ⸮⸮'I⸮)j⸮H(⸮5⸮ꨨH⸮)⸮Қ⸮Ҫ⸮Z⸮⸮j 12:34:58.138 -> 12:34:58.138 -> Arduino Received: 12:34:58.172 -> 12:34:58.172 -> Arduino Received: OK A+⸮1-⸮jRb҂⸮jjZ⸮⸮Ҫ⸮Z⸮⸮j 12:34:58.207 -> 12:34:58.207 -> Arduino Received:

score 1 · Accepted Answer · answered Oct 04 '20 at 10:59

1

Try this:

#include <SoftwareSerial.h>

SoftwareSerial gsm(10, 11);
String inData;

void setup() {
    Serial.begin(9600);
    gsm.begin(9600);
    delay(5000);
}

void loop() {

    inData = "";

    gsm.println("AT+CCLK?");
    delay(500);

    while (gsm.available()) {
        inData += char(gsm.read());
    }

    Serial.print("Arduino Received: ");
    Serial.println(inData);

    delay(500);
}

answered Oct 04 '20 at 10:59

Danny_ds

11,201
1
24
46

Thanks for your code, it worked perfectly and after removing the 500 ms delay also the data was coming perfectly. thanks a lot – Electro Tech Oct 05 '20 at 13:13

score 1 · Answer 2 · answered Oct 04 '20 at 12:37

1

@Danny_ds

doing while (gsm.available()) { inData += char(gsm.read()); }

will empty the incoming buffer quicker than it is filled in if the GSM did not get a chance to fill up the buffer during the 500ms pause you provided before.

The buffer being also only 64 bytes deep, at 9600 bauds you can receive 480 characters in those 500ms.. it means that if the answer is longer than 64 bytes, you'll loose everything else.

so in a nutshell, you are not guaranteed to see the full answer.

Proper way of doing this is to await for the full answer as described in the documentation (usually you get an "OK\r\n" at the end of the answer) or a timeout whatever comes first.

answered Oct 04 '20 at 12:37

A No nymous

11
1

You are probably right (unable to test this here right now, but I have indeed seen code where there was a small delay in that read-loop, which is also not the right way). Please feel free to update the code and put it in your answer. I'll give you an upvote and remove mine. – Danny_ds Oct 04 '20 at 13:12
Thanks for your suggestion at end of to check OK\r\n. – Electro Tech Oct 05 '20 at 13:08

How to get live GPS Sim800 Module RTC time on Arduino

2 Answers2