How do I "hold" a variable until It changes to one of my other variable IF options?
I have an arduino gsm shield(official) I want to be able to send it a message 1(on) or 2(off) to simply turn a light on or off When I sent the number 1 the light goes on for a short while and then it goes off again because the message gets erased but when I remove the erase feature the light just stays on when I send 2. I Probobly made some stuff that doesn't make sense since i'm still new to arduino.
Here is my program I have no idea what to do:
#include <GSM.h>
// PIN Number for the SIM
#define PINNUMBER "(my pin number)"
#define led 13
// initialize the library instances
GSM gsmAccess;
GSM_SMS sms;
// Array to hold the number a SMS is retreived from
char senderNumber[20];
void setup() {
// initialize serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
pinMode(led,OUTPUT);
Serial.println("SMS Messages Receiver");
// connection state
boolean notConnected = true;
// Start GSM connection
while (notConnected) {
if (gsmAccess.begin(PINNUMBER) == GSM_READY) {
notConnected = false;
} else {
Serial.println("Not connected");
delay(1000);
}
}
Serial.println("GSM initialized");
Serial.println("Waiting for messages");
}
void loop() {
char c;
if (sms.available()) {
Serial.println("Message received from:");
sms.remoteNumber(senderNumber, 20);
Serial.println(senderNumber);
// Any messages starting with # should be discarded
if (sms.peek() == '#') {
Serial.println("Discarded SMS");
sms.flush();
}
// Read message bytes and print them
while(c = sms.read())
Serial.println(c);
if (c == 1){
digitalWrite(led,HIGH);
Serial.println("received command");
}
if (c == 2){
digitalWrite(led,LOW);
Serial.println("received command2");
}
delay(5000);
Serial.println("\nEND OF MESSAGE");
sms.flush();//delete message
Serial.println("MESSAGE DELETED");
}
delay(3000);
}
Please help
char c;This resets the value of c each time through loop(). Because c is a local variable its value cannot be predicted.
Change the declaration to
static char c;and once its value has been set it won't change unless you explicitly change it. Note that you only do anything with the value of c when a new message is received so does it actually matter if it is reset to another value ?
Will definitely try thank you!
The IF doesn't seem to be true it passes by the IF statement. should I rather use 1, '1' or "1" or what else?
Thank you soooo much it works perfecly now, now I just need to figure this out /|
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If you are typing in '1' on the keyboard, then your code should be looking for the character '1'.
If you are sending the binary number 1 then the code should be looking for the byte 1.
// Read message bytes and print them
while(c = sms.read())
Serial.println(c);
if (c == 1){
// should not come here too often ?
}
Not sure when sms.read() does return a binary 0, but that's the only case when thewhileends.
When you're sure c == 0 after the while, anif does not make sense.
I doubt this is your intention.
( Do we miss some brackets ? )
If something works perfectly, then that's probably not the code you posted 
michael_x:
Not sure when sms.read() does return a binary 0, but that's the only case when thewhileends.
When you're sure c == 0 after the while, anif does not make sense.
I doubt this is your intention.
( Do we miss some brackets ? )
If something works perfectly, then that's probably not the code you posted
Thanks! missed that now it works 100%
#include <GSM.h>
// PIN Number for the SIM
#define PINNUMBER "MY PIN :)"
#define led 13
// initialize the library instances
GSM gsmAccess;
GSM_SMS sms;
// Array to hold the number a SMS is retreived from
char senderNumber[20];
char x;
void setup() {
// initialize serial communications and wait for port to open:
Serial.begin(9600);
x = 'k';
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
pinMode(led,OUTPUT);
Serial.println("SMS Messages Receiver");
// connection state
boolean notConnected = true;
// Start GSM connection
while (notConnected) {
if (gsmAccess.begin(PINNUMBER) == GSM_READY) {
notConnected = false;
} else {
Serial.println("Not connected");
delay(1000);
}
}
Serial.println("GSM initialized");
Serial.println("Waiting for messages");
}
void loop() {
static char c;
// Serial.println("1");
//Serial.println(x);
if (sms.available()) {
Serial.println("Message received from:");
sms.remoteNumber(senderNumber, 20);
Serial.println(senderNumber);
// Any messages starting with # should be discarded
if (sms.peek() == '#') {
Serial.println("Discarded SMS");
sms.flush();
}
// Read message bytes and print them
Serial.println("by sms");
c = sms.read();
Serial.println(c);
// Serial.println(c.length());
Serial.println(x);
// Serial.print;(x.length());
delay(2000);
if (c == x){
Serial.println("1a);
delay(1000);
digitalWrite(led,HIGH);
Serial.println("received command");
Serial.println("2");
}
if (c == '2'){
Serial.println("1b");
digitalWrite(led,LOW);
Serial.println("received command2");
}
delay(5000);
Serial.println("/nEND OF MESSAGE");
sms.flush();//delete message
Serial.println("MESSAGE DELETED");
Serial.print("3");
}
delay(3000);
}