I finally found a documentation about RF X10 protocol:
X10 RF Receiver.pdf
I've created the following working code for Arduino Nano :
/*
* Custom sensor (base code)
*
* Emission in RF 433MHz with the X10 protocol for Domoticz
*
* Hardware :
* Arduino Pro Mini 5V (4€) https://www.amazon.fr/gp/product/B00QPUEFNW/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
* RF 433MHz emitter/receiver (3€) https://www.amazon.fr/HDigiWorld-metteur-cepteur-commande-Arduino/dp/B00JTQI39G/ref=sr_1_3?s=computers&ie=UTF8&qid=1470813610&sr=1-3&keywords=433
* Note: only the emitter is used
* 3 wires : VCC, GND, Signal (on Arduino pin 2)
*
* Documentation found for RF X10: http://www.printcapture.com/files/X10_RF_Receiver.pdf
*
* Example of malformed data received in RfxMngr in mode "nodec" (before this code was correctly debugged) :
*
* Packettype = UNDECODED RF Message
* UNDECODED NEC:1C515C86F0
*
*
* Correct data that is now receveived by RfxMngr with this program :
*
*------------------------------------------------
* Packettype = Lighting1
* subtype = X10
* Sequence nbr = 13
* housecode = D
* unitcode = 1
* Command = On
* Signal level = 7 -64dBm
*------------------------------------------------
* Packettype = Lighting1
* subtype = X10
* Sequence nbr = 14
* housecode = D
* unitcode = 1
* Command = Off
* Signal level = 7 -64dBm
*------------------------------------------------
*/
const int pin_emit = 2; // Signal pin for RF433 emitter
const int pin_led = 13; // Internal LED : it will be ON when the "On" command is sent in RF, and OFF the the "Off" command is sent (changed each 60s)
const unsigned int X10_A1_ON = 0x00;
const unsigned int X10_A1_OFF = 0x20;
const unsigned int X10_address = 5; // this is Housecode. In my case 5 results in "D" house code
unsigned int X10_data = X10_A1_ON; // command. I have implemented only On/Off for unit code 1
void setup() {
pinMode(pin_led, OUTPUT);
pinMode(pin_emit, OUTPUT);
digitalWrite(pin_emit, LOW);
}
/**
* Bit to 0 : 1.125ms between rising edges, so before next bit
*/
void X10_sendBit_zero()
{
digitalWrite(pin_emit, HIGH);
delayMicroseconds(555); // Arbitrary value: I took around 1.125ms divided by two for the "VCC" state.
digitalWrite(pin_emit, LOW);
delayMicroseconds(570); // Total 555+570 : 1125µs = 1.125ms
}
/**
* Bit à 1 : 2.25ms entre les "rising edges"
*/
void X10_sendBit_one()
{
digitalWrite(pin_emit, HIGH);
delayMicroseconds(555); // Arbitrary value: I took around 1.125ms divided by two for the "VCC" state.
digitalWrite(pin_emit, LOW);
delayMicroseconds(1695); // Total 555+1695 : 2250µs = 2.250ms
}
void X10_send8bits(unsigned int data)
{
// - Send the 8 bits, and then the complementary of the 8 bits.
// from documentation: "Within each byte, bit7 is received first and bit0 last"
int mask = 0x80;
for(int i = 0; i < 8; i++)
{
int bit = mask & data;
if (bit == 0)
X10_sendBit_zero();
else
X10_sendBit_one();
mask = mask >> 1;
}
}
/**
* Sending a byte consists of sending this byte, and then sending the opposite of the same byte.
* As we send the opposite as well as the data, the total duration is always the same : 8 * (1.125ms+2.250ms) = 8 * 3.375 = total of 27ms
*/
void X10_sendByte(unsigned int data)
{
X10_send8bits(data);
X10_send8bits(~data);
}
/**
* Send a complete X10 packet
*
* Total duration :
* (9ms + 4.5ms) + (27ms + 27ms) + 0.555ms + 40ms = 108.055 ms
* from doc: "It appears, from articles on the 'net, that other people have seen a range from 95 msec to 116 msec for various transmitters and that standard X-10 transceivers can tolerate timing variations of 30-35% from nominal."
*/
void X10_sendState_once(unsigned int data)
{
// - Header
digitalWrite(pin_emit, HIGH); // "Burst" de 9ms
delayMicroseconds(9000);
digitalWrite(pin_emit, LOW); // Silence de 4.5ms
delayMicroseconds(4500);
// - Data
X10_sendByte(0x50); // - Address
X10_sendByte(data); // - Data
// - Send a last rising edge to validate last bit
digitalWrite(pin_emit, HIGH);
delayMicroseconds(555); // Arbitraty value (but always the same), for "VCC" state.
// - Footer
digitalWrite(pin_emit, LOW); // Silence de 40ms pour signifier la fin de l'émission
delayMicroseconds(40000);
}
/**
* Send a complete packet multiple times (this X10 protocol has not ACK))
* From doc: "Most X-10 RF transmitters send a minimum of five copies of the code separated by 40 msec silences although some can send single bursts."
*
* 5 times 108.055ms = 540.275 ms, half a second
*/
void X10_sendState(unsigned int data)
{
// - "clean" to be sure to have a zero for the first rising edge on init
digitalWrite(pin_emit, LOW);
delay(1);
// - Send 5 time complete packet
for(int repeat=0 ; repeat<5 ; repeat++)
X10_sendState_once(data);
}
void loop() {
if(X10_data == X10_A1_ON)
digitalWrite(pin_led, HIGH);
else
digitalWrite(pin_led, LOW);
X10_sendState(X10_data);
delay(60000); // 1 minute
// - I change state each 60 seconds to see changes in Domoticz
if(X10_data == X10_A1_ON)
X10_data = X10_A1_OFF;
else
X10_data = X10_A1_ON;
}
By changing House code and data, it is now possible to create our own RF sensors.
