how to text sensor data off periodically (arduino uno + tinysine gsm shield)

Im doing a rain gauge…

I get it to text me when the shield comes on

i can get the sensor data to display nicely in the serial monitor


etc etc.

but can someone please tell how to text the latest rainfall information say every 15mins and then reset the counter!

thanks so much

StateChangeDetection_gsm.ino (2.87 KB)

#include “SIM900.h”
#include <SoftwareSerial.h>

#include “sms.h”

State change detection (edge detection)

Often, you don’t need to know the state of a digital input all the time,
but you just need to know when the input changes from one state to another.
For example, you want to know when a button goes from OFF to ON. This is called
state change detection, or edge detection.

This example shows how to detect when a button or button changes from off to on
and on to off.

The circuit:

  • pushbutton attached to pin 2 from +5V
  • 10K resistor attached to pin 2 from ground
  • LED attached from pin 13 to ground (or use the built-in LED on
    most Arduino boards)

created 27 Sep 2005
modified 30 Aug 2011
by Tom Igoe

This example code is in the public domain.


// this constant won’t change:
const int buttonPin = 4; // the pin that the pushbutton is attached to
const int ledPin = 13; // the pin that the LED is attached to

// Variables will change:
int buttonPushCounter = 0; // counter for the number of button presses
int buttonState = 0; // current state of the button
int lastButtonState = 0; // previous state of the button
float myval;

int numdata;
boolean started=false;
char smsbuffer[160];
char n[20];

//debug begin
char sms_position;
char phone_number[20]; // array for the phone number string
char sms_text[100];
int i;
//debug end

void setup()
// initialize the button pin as a input:
pinMode(buttonPin, INPUT);
// initialize the LED as an output:
pinMode(ledPin, OUTPUT);
// initialize serial communication:
Serial.println (“Arduino on”);
if (gsm.begin(4800));
Serial.print (“GSM on”);
if (sms.SendSMS("+27630812488", “power on”));
Serial.println("\nSMS sent OK");

void loop() {
// read the pushbutton input pin:
buttonState = digitalRead(buttonPin);

// compare the buttonState to its previous state
if (buttonState != lastButtonState) {
// if the state has changed, increment the counter
if (buttonState == HIGH) {
// if the current state is HIGH then the button
// wend from off to on:
myval += 0.2;
Serial.print("Rainfall: ");
Serial.print (myval);

else {
// if the current state is LOW then the button
// wend from on to off:
// Delay a little bit to avoid bouncing
// save the current state as the last state,
//for next time through the loop
lastButtonState = buttonState;

// turns on the LED every four button pushes by
// checking the modulo of the button push counter.
// the modulo function gives you the remainder of
// the division of two numbers:
if (buttonPushCounter % 4 == 0) {
digitalWrite(ledPin, HIGH);
} else {
digitalWrite(ledPin, LOW);