Hello,
I have just started in the world of domotics.
Bought the cheap 433 transmitter and receiver "DIY 433MHz Wireless Receiving Module Superregeneration for Arduino "
Connected them to my arduino Nano but am not able to receive any stable signal.
I have used all libraries like MySensors and Remote switch. Using these NOTHING is received by the Arduino. Receiver output is connected to the D2 pin on my arduino.
I have found the below code. When I load this in the Arduino at least the serial monitor does give me some output but never the same even if
I press the same button again 
I even tried a different arduino ( different type of board )
I tried a different pin D3. Does the nano support interupts?
I tried a different receiver.
Does anybody recognize what I am doing wrong?? or can give me a suggestion?
I could not find and topic on this one. Apologies if there is a similar topic already.
Cheers, and many thanks for your time.
Frank
Init : Start decoding
Found Header : 3 bits word
001 => 1
Found Header : 15 bits word
001000001010001 => 1051
Found Header : 1 bits word
1 => 1
Found Header : 1 bits word
1 => 1
Found Header : 3 bits word
001 => 1
Found Header : 7 bits word
0000001 => 1
/*
This is just a naive trial for decoding streams for 433MHz remote controls
The aim is just to have differents results for differents remote buttons
Image of the remote control (Jolly Open) : http://mgrigaut.free.fr/arduino/Plip.jpg
Output signal from the 433MHz receiver : http://mgrigaut.free.fr/arduino/Jolly2.gif (probably NRZ)
*/
// Led on Arduino hardware (I use Arduino Nano)
const int led = 13; // Blink when code found
// debug=1 for debugging
const int debug=1;
// input pin that receive signal
const int sig = 2;
// Code timing :
// Short bit is 600 us ; Long bit is 1.2 ms so 900 us is a good threshold to compare.
const int shortbit=9; // 0.9 ms (9 times 100 microseconds)
int maxlength; // 5 time shortbit (computed in Setup)
const int headerlength=25; // 25ms minimum (different units than shortbit)
int last = 0;
int cur = 0;
int nochange = 0; // Number of times (of 1 ms) the signal does not change
char resu[32] = ""; // Contains binary code as as string of '0' and '1'
int dur=0; // The measured duration between two changes
int bit=0; // the decoded bit (0 or 1)
int nb=0;
unsigned long HexCode=0; // The found code
void setup() {
Serial.begin(9600);
pinMode(led, OUTPUT);
pinMode(sig, INPUT);
maxlength=5 * shortbit;
Serial.print("\nInit : Start decoding\n");
}
void loop() {
// Header detection :
cur=digitalRead(sig);
// Wait for a long stable signal :
if (last!=cur) {
// Not stable yet
last=cur;
nochange=0;
} else {
nochange++;
if (nochange>headerlength) {
// Header found
// pri() will print only if debug=1
pri("Found Header : ");
// Wait end of header (at 0.1 ms precision)
while(cur==last) {
cur=digitalRead(sig);
delayMicroseconds(100);
}
// Start decode whatever comes after this end of header :
nb=my_decode();
// nb is the number of bits detected
// If the expected number of bits is known, then the following
// condition can be more precise to have a better filtering.
if (nb>0) {
// All the following stuff is mainly for debugging
pri((String)nb);
pri(" bits word\n");
pri(resu);
pri(" => ");
// Build a filter to print out only known codes :
// Now, this is the only useful info (printed even if debug=0) :
Serial.print(HexCode,HEX);
if (HexCode==0xCCCCCD) {
Serial.print(" DOOR SECTIO");
}
if (HexCode==0xCCCCD3) {
Serial.print(" DOOR PORTAL");
}
Serial.println();
// Blink led :
// Not useful since Serial.print makes another led blink on Arduino Nano
digitalWrite(led, HIGH);
delay(5);
digitalWrite(led, LOW);
} else {
pri("Noise...\n");
}
// Done. Wait now for a new header
nochange=0;
}
}
// Wait every ms for the header
delay(1);
}
int my_decode() {
int nbits=0;
cur=last;
resu[0]='\0';
// Duration (in 0.1 ms):
dur=0;
// Result :
HexCode=0;
while(dur<maxlength) {
dur=0;
// Wait for a change
while(cur==last) {
cur=digitalRead(sig);
delayMicroseconds(100);
dur++;
}
// So, state has changed now.
last=cur;
// this coding does not follow any specs.
// See if duration is greater than 900 us :
// This If then else is there to spend the same time in each branch
if(dur>shortbit) {
bit=1;
} else {
bit=0;
}
// Add bit to string resu :
sprintf(resu,"%s%d",resu,bit);
// Shift HexCode 1 bit to multiply it by 2 :
HexCode=HexCode<<1;
// Then add bit to it :
HexCode+=bit;
// Increment number of bits
nbits++;
// Avoid overflow :
if (nbits>31) {
nbits=0;
// exit loop :
dur=maxlength+1;
}
}
return(nbits);
}
void pri(String truc) {
if (debug==1) {
Serial.print(truc);
}
}
