Aller au contenu


Utilisation Station Météo RF433Mhz avec Arduino

Niveau:2

Introduction:

Dans ce chapitre, nous allons voir comment lire les données du module TS-WS-07-XF avec un Arduino.

Descriptif du matériel:

Module TS-WS-07-XF:

Fréquence : 433,92MHz
Alimentation : 2 piles 1.5V
Mesure la température et l’hygrométrie.

Documentation :TS-WS-07.pdf

Récepteur RF :

Il existe plusieurs modèles de module RF avec des prix très variable suivant la qualité du module.

Voici le modèle très bas prix qui fonctionne mais à une réception limitée en distance.

J’utilise pour mon montage le modèle AM-RX9-433P.

Documentation:AM-RX9-433P.pdf

Raccordement:

Vérifier que les broches sont bien identique pour votre module.

Récepteur:

VCC =>+5 Volt de la carte Arduino

GND=>GND de la carte Arduino.

DATA => broche 2 ou  3 de la carte Arduino.

Programme:

/*
Based on Andrew's sketch for capturing data from Ambient F007th Thermo-Hygrometer less the uploading it to Xively via Wifi and with the addition of a checksum check.

Inspired by the many weather station hackers who have gone before,
Only possible thanks to the invaluable help and support on the Arduino forums.

With particular thanks to

Rob Ward (whose Manchester Encoding reading by delay rather than interrupt
is the basis of this code)
https://github.com/robwlakes/ArduinoWeatherOS

The work of 3zero8 capturing and analysing the F007th data
http://forum.arduino.cc/index.php?topic=214436.0

The work of Volgy capturing and analysing the F007th data
https://github.com/volgy/gr-ambient

Marco Schwartz for showing how to send sensor data to websites
http://www.openhomeautomation.net/

The forum contributions of;
dc42: showing how to create 5 minute samples.
jremington: suggesting how to construct error checking using averages (although not used this is where the idea of using newtemp and newhum for error checking originated)
Krodal: for his 6 lines of code in the forum thread "Compare two sensor values"

This example code is in the public domain.

Additional work by Ron Lewis on reverse engineering the checksum

What this code does:
Captures Ambient F007th Thermo-Hygrometer data packets by;
Identifying a header of at least 10 rising edges (manchester encoding binary 1s)
Synchs the data correctly within byte boundaries
Distinguishes between F007th data packets and other 434Mhz signals with equivalent header by checking value of sensor ID byte
Correctly identifies positive and negative temperature values to 1 decimal place for up to 8 channels
Correctly identifies humidity values for up to 8 channels
Error checks data by rejecting;
humidity value outside the range 1 to 100%
bad checksums

Hardware to use with this code
6 F007th Thermo-Hygrometer set to different channels (can be adapted for between 1 and 8)
A 434Mhz receiver
17cm strand of CAT-5 cable as an antenna.


Code optimisation
In order to improve reliability this code has been optimised to remove float values except when sending to Xively.
This code does not provide any output to the serial monitor on what is happening, see earlier versions for printouts.

F007th Ambient Thermo-Hygrometer
Sample Data:
0 1 2 3 4 5 6 7
FD 45 4F 04 4B 0B 52 0
0 1 2 3 4 5 6 7 8 9 A B C D E
11111101 01000101 01001111 00000100 01001011 00001011 01010010 0000
hhhhhhhh SSSSSSSS NRRRRRRR bCCCTTTT TTTTTTTT HHHHHHHH CCCCCCCC ????

Channel 1 F007th sensor displaying 21.1 Centigrade and 11% RH

hhhhhhhh = header with final 01 before data packet starts (note using this sketch the header 01 is omitted when the binary is displayed)
SSSSSSSS = sensor ID, F007th = Ox45
NRRRRRRR = Rolling Code Byte? Resets each time the battery is changed
b = battery indicator?
CCC = Channel identifier, channels 1 to 8 can be selected on the F007th unit using dipswitches. Channel 1 => 000, Channel 2 => 001, Channel 3 => 010 etc.
TTTT TTTTTTTT = 12 bit temperature data.
To obtain F: convert binary to decimal, take away 400 and divide by 10 e.g. (using example above) 010001001011 => 1099
(1099-400)/10= 69.9F
To obtain C: convert binary to decimal, take away 720 and multiply by 0.0556 e.g.
0.0556*(1099-720)= 21.1C
HHHHHHHH = 8 bit humidity in binary. e.g. (using example above) 00001011 => 11
CCCCCCCC = checksum? Note that this sketch only looks at the first 6 bytes and ignores the checksum

*/

/* Christophe Caron
www.caron.ws
V1.0.0 24/03/2019
*/

#define MAX_BYTES 7
#define countof(x) (sizeof(x)/sizeof(x[0]))
// Interface Definitions
int RxPin = 2; //The number of signal from the Rx

// Variables for Manchester Receiver Logic:
word sDelay = 242; //Small Delay about 1/4 of bit duration
word lDelay = 484; //Long Delay about 1/2 of bit duration, 1/4 + 1/2 = 3/4
byte polarity = 1; //0 for lo->hi==1 or 1 for hi->lo==1 for Polarity, sets tempBit at start
byte tempBit = 1; //Reflects the required transition polarity
boolean firstZero = false;//flags when the first '0' is found.
boolean noErrors = true; //flags if signal does not follow Manchester conventions
//variables for Header detection
byte headerBits = 10; //The number of ones expected to make a valid header
byte headerHits = 0; //Counts the number of "1"s to determine a header
//Variables for Byte storage
boolean sync0In = true; //Expecting sync0 to be inside byte boundaries, set to false for sync0 outside bytes
byte dataByte = 0xFF; //Accumulates the bit information
byte nosBits = 6; //Counts to 8 bits within a dataByte
byte maxBytes = MAX_BYTES; //Set the bytes collected after each header. NB if set too high, any end noise will cause an error
byte nosBytes = 0; //Counter stays within 0 -> maxBytes
//Variables for multiple packets
byte bank = 0; //Points to the array of 0 to 3 banks of results from up to 4 last data downloads
byte nosRepeats = 3; //Number of times the header/data is fetched at least once or up to 4 times
//Banks for multiple packets if required (at least one will be needed)
byte manchester[MAX_BYTES]; //Stores banks of manchester pattern decoded on the fly

// Variables to prepare recorded values for Ambient

byte stnId = 0; //Identifies the channel number
int dataType = 0; //Identifies the Ambient Thermo-Hygrometer code
int Newtemp = 0;
int Newhum = 0;
int ChanTemp[9]; //make one extra so we can index 1 relative
int ChanHum[9];


void setup()
{
Serial.begin(115200);
pinMode(RxPin, INPUT);
eraseManchester(); //clear the array to different nos cause if all zeroes it might think that is a valid 3 packets ie all equal
}


// Main RF, to find header, then sync in with it and get a packet.

void loop()
{
lecture();

} //end of mainloop


void lecture() {
tempBit = polarity; //these begin the same for a packet
noErrors = true;
firstZero = false;
headerHits = 0;
nosBits = 6;
nosBytes = 0;
while (noErrors && (nosBytes < maxBytes))
{
while (digitalRead(RxPin) != tempBit)
{
//pause here until a transition is found
}//at Data transition, half way through bit pattern, this should be where RxPin==tempBit
delayMicroseconds(sDelay);//skip ahead to 3/4 of the bit pattern
// 3/4 the way through, if RxPin has changed it is definitely an error

if (digitalRead(RxPin) != tempBit)
{
noErrors = false; //something has gone wrong, polarity has changed too early, ie always an error
}//exit and retry
else
{
delayMicroseconds(lDelay);
//now 1 quarter into the next bit pattern,
if (digitalRead(RxPin) == tempBit) //if RxPin has not swapped, then bitWaveform is swapping
{
//If the header is done, then it means data change is occuring ie 1->0, or 0->1
//data transition detection must swap, so it loops for the opposite transitions
tempBit = tempBit ^ 1;
}//end of detecting no transition at end of bit waveform, ie end of previous bit waveform same as start of next bitwaveform

//Now process the tempBit state and make data definite 0 or 1's, allow possibility of Pos or Neg Polarity
byte bitState = tempBit ^ polarity;//if polarity=1, invert the tempBit or if polarity=0, leave it alone.
if (bitState == 1) //1 data could be header or packet
{
if (!firstZero)
{
headerHits++;
}
else
{
add(bitState);//already seen first zero so add bit in
}
}//end of dealing with ones
else
{ //bitState==0 could first error, first zero or packet
// if it is header there must be no "zeroes" or errors
if (headerHits < headerBits)
{
//Still in header checking phase, more header hits required
noErrors = false; //landing here means header is corrupted, so it is probably an error
}//end of detecting a "zero" inside a header
else
{
//we have our header, chewed up any excess and here is a zero
if (!firstZero) //if first zero, it has not been found previously
{
firstZero = true;
add(bitState);//Add first zero to bytes
//Serial.print("!");
}//end of finding first zero
else
{
add(bitState);
}//end of adding a zero bit
}//end of dealing with a first zero
}//end of dealing with zero's (in header, first or later zeroes)
}//end of first error check
}//end of while noErrors=true and getting packet of bytes
}

//Read the binary data from the bank and apply conversions where necessary to scale and format data

void add(byte bitData)
{
dataByte = (dataByte << 1) | bitData;
nosBits++;
if (nosBits == 8)
{
nosBits = 0;
manchester[nosBytes] = dataByte;
nosBytes++;
}
if (nosBytes == maxBytes)
{
dataByte = 0xFF;
// Subroutines to extract data from Manchester encoding and error checking

// Identify channels 1 to 8 by looking at 3 bits in byte 3
int stnId = ((manchester[3] & B01110000) / 16) + 1;

// Identify sensor by looking for sensorID in byte 1 (F007th Ambient Thermo-Hygrometer = 0x45)
dataType = manchester[1];

// Gets raw temperature from bytes 3 and 4 (note this is neither C or F but a value from the sensor)
Newtemp = (float((manchester[3] & B00000111) * 256) + manchester[4]);

// Gets humidity data from byte 5
Newhum = (manchester [5]);


if ( Checksum (countof(manchester) - 2, manchester + 1) == manchester[MAX_BYTES - 1])
{
// Checks sensor is a F007th with a valid humidity reading equal or less than 100
if ((dataType == 0x45) && (Newhum <= 100))
{

ChanTemp[stnId] = Newtemp;
ChanHum[stnId] = Newhum;

// print raw data
char Buff[128];
char str_Tvalue[6];
float Tvalue=((float((Newtemp - 720) * 0.0556)));
dtostrf(Tvalue, 4, 2, str_Tvalue);
for (int i = 0; i < maxBytes; i++)
{
sprintf(&Buff[i * 3], "%02X ", manchester[i]);
}
// 123456789 123456789 1234
// Channel=1 F=123.1 H=12%<
sprintf(&Buff[maxBytes * 3], " Canal: %d Température: %s °C Hygrométrie:%d%%\n",
stnId,
str_Tvalue,
Newhum);
Serial.print(Buff);
Serial.print("Canal:");
Serial.println(stnId);
Serial.print("Température:");
Serial.print(Tvalue,2);
Serial.println(" °C");
Serial.print("Hygrométrie:");
Serial.print(Newhum);
Serial.println(" %");
}
}
}
}

void eraseManchester()
{
for ( int j = 0; j < 4; j++)
{
manchester[j] = j;
}
}


uint8_t Checksum(int length, uint8_t *buff)
{
uint8_t mask = 0x7C;
uint8_t checksum = 0x64;
uint8_t data;
int byteCnt;

for ( byteCnt = 0; byteCnt < length; byteCnt++)
{
int bitCnt;
data = buff[byteCnt];

for ( bitCnt = 7; bitCnt >= 0 ; bitCnt-- )
{
uint8_t bit;

// Rotate mask right
bit = mask & 1;
mask = (mask >> 1 ) | (mask << 7);
if ( bit )
{
mask ^= 0x18;
}

// XOR mask into checksum if data bit is 1
if ( data & 0x80 )
{
checksum ^= mask;
}
data <<= 1;
}
}
return checksum;
}

Code source: RF_Temp.zip

Résultat:

Nombre de visiteurs depuis le 07/2012: