Send Temperature, Humidity and Pressure data as an Oregon BTHR918N Sensor using Arduino and 433MHz Transmitter

README.txt

Based on:
- original work from found on this place:
  http://www.connectingstuff.net/blog/encodage-protocoles-oregon-scientific-sur-arduino/
- Oregon Protocol description:
  http://wmrx00.sourceforge.net/Arduino/OregonScientific-RF-Protocols.pdf
- BTHR918N frame description from this site:
  http://syno.haeflinger.com/index.php/Domotique#BTHR918N

I was able to get a correct signal emitted from a simple RF433MHz transmitter plugged on an Arduino nano, 
decoded by the RFXCOM Rfxtrx433e module, and then correctly displayed on Domoticz.

BTHR918N_ArduinoSender.ino

/*
 * connectingStuff, Oregon Scientific v2.1 Emitter
 * http://www.connectingstuff.net/blog/encodage-protocoles-oregon-scientific-sur-arduino/
 *
 * Copyright (C) 2013 olivier.lebrun@gmail.com
 * Modified by Jonathan Martin <therouquinblanc@gmail.com>, August 2015
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/
 
#define MODE_0 0 // Temperature only [THN132N]
#define MODE_1 1 // Temperature + Humidity [THGR2228N]
#define MODE_2 2 // Temperature + Humidity + Baro() [BTHR918N]

#define MODE MODE_2
 
const byte TX_PIN = 6;
 
const unsigned long TIME = 512;
const unsigned long TWOTIME = TIME*2;
 
#define SEND_HIGH() digitalWrite(TX_PIN, HIGH)
#define SEND_LOW() digitalWrite(TX_PIN, LOW)
 
// Buffer for Oregon message
#if MODE == MODE_0
  byte OregonMessageBuffer[8];
#elif MODE == MODE_1
  byte OregonMessageBuffer[9];
#elif MODE == MODE_2
  byte OregonMessageBuffer[11];
#else
  #error mode unknown
#endif
 
/**
 * \brief    Send logical "0" over RF
 * \details  azero bit be represented by an off-to-on transition
 * \         of the RF signal at the middle of a clock period.
 * \         Remenber, the Oregon v2.1 protocol add an inverted bit first 
 */
inline void sendZero(void) 
{
  SEND_HIGH();
  delayMicroseconds(TIME);
  SEND_LOW();
  delayMicroseconds(TWOTIME);
  SEND_HIGH();
  delayMicroseconds(TIME);
}
 
/**
 * \brief    Send logical "1" over RF
 * \details  a one bit be represented by an on-to-off transition
 * \         of the RF signal at the middle of a clock period.
 * \         Remenber, the Oregon v2.1 protocol add an inverted bit first 
 */
inline void sendOne(void) 
{
   SEND_LOW();
   delayMicroseconds(TIME);
   SEND_HIGH();
   delayMicroseconds(TWOTIME);
   SEND_LOW();
   delayMicroseconds(TIME);
}
 
/**
* Send a bits quarter (4 bits = MSB from 8 bits value) over RF
*
* @param data Source data to process and sent
*/
 
/**
 * \brief    Send a bits quarter (4 bits = MSB from 8 bits value) over RF
 * \param    data   Data to send
 */
inline void sendQuarterMSB(const byte data) 
{
  (bitRead(data, 4)) ? sendOne() : sendZero();
  (bitRead(data, 5)) ? sendOne() : sendZero();
  (bitRead(data, 6)) ? sendOne() : sendZero();
  (bitRead(data, 7)) ? sendOne() : sendZero();
}
 
/**
 * \brief    Send a bits quarter (4 bits = LSB from 8 bits value) over RF
 * \param    data   Data to send
 */
inline void sendQuarterLSB(const byte data) 
{
  (bitRead(data, 0)) ? sendOne() : sendZero();
  (bitRead(data, 1)) ? sendOne() : sendZero();
  (bitRead(data, 2)) ? sendOne() : sendZero();
  (bitRead(data, 3)) ? sendOne() : sendZero();
}
 
/******************************************************************/
/******************************************************************/
/******************************************************************/
 
/**
 * \brief    Send a buffer over RF
 * \param    data   Data to send
 * \param    size   size of data to send
 */
void sendData(byte *data, byte size)
{
  for(byte i = 0; i < size; ++i)
  {
    sendQuarterLSB(data[i]);
    sendQuarterMSB(data[i]);
  }
}
 
/**
 * \brief    Send an Oregon message
 * \param    data   The Oregon message
 */
void sendOregon(byte *data, byte size)
{
    sendPreamble();
    //sendSync();
    sendData(data, size);
    sendPostamble();
}
 
/**
 * \brief    Send preamble
 * \details  The preamble consists of 16 "1" bits
 */
inline void sendPreamble(void)
{
  byte PREAMBLE[]={0xFF,0xFF};
  sendData(PREAMBLE, 2);
}
 
/**
 * \brief    Send postamble
 * \details  The postamble consists of 8 "0" bits
 */
inline void sendPostamble(void)
{
#if MODE == MODE_0
  sendQuarterLSB(0x00);
#else
  byte POSTAMBLE[]={0x00};
  sendData(POSTAMBLE, 1);
#endif
}
 
/**
 * \brief    Send sync nibble
 * \details  The sync is 0xA. It is not use in this version since the sync nibble
 * \         is include in the Oregon message to send.
 */
inline void sendSync(void)
{
  sendQuarterLSB(0xA);
}
 
/******************************************************************/
/******************************************************************/
/******************************************************************/
 
/**
 * \brief    Set the sensor type
 * \param    data       Oregon message
 * \param    type       Sensor type
 */
inline void setType(byte *data, byte* type) 
{
  data[0] = type[0];
  data[1] = type[1];
}
 
/**
 * \brief    Set the sensor channel
 * \param    data       Oregon message
 * \param    channel    Sensor channel (0x10, 0x20, 0x30)
 */
inline void setChannel(byte *data, byte channel) 
{
    data[2] = channel;
}
 
/**
 * \brief    Set the sensor ID
 * \param    data       Oregon message
 * \param    ID         Sensor unique ID
 */
inline void setId(byte *data, byte ID) 
{
  data[3] = ID;
}
 
/**
 * \brief    Set the sensor battery level
 * \param    data       Oregon message
 * \param    level      Battery level (0 = low, 1 = high)
 */
void setBatteryLevel(byte *data, byte level)
{
  if(!level) data[4] = 0x0C;
  else data[4] = 0x00;
}
 
/**
 * \brief    Set the sensor temperature
 * \param    data       Oregon message
 * \param    temp       the temperature
 */
void setTemperature(byte *data, float temp) 
{
  // Set temperature sign
  if(temp < 0)
  {
    data[6] = 0x08;
    temp *= -1;  
  }
  else
  {
    data[6] = 0x00;
  }
 
  // Determine decimal and float part
  int tempInt = (int)temp;
  int td = (int)(tempInt / 10);
  int tf = (int)round((float)((float)tempInt/10 - (float)td) * 10);
 
  int tempFloat =  (int)round((float)(temp - (float)tempInt) * 10);
 
  // Set temperature decimal part
  data[5] = (td << 4);
  data[5] |= tf;
 
  // Set temperature float part
  data[4] |= (tempFloat << 4);
}
 
/**
 * \brief    Set the sensor humidity
 * \param    data       Oregon message
 * \param    hum        the humidity
 */
void setHumidity(byte* data, byte hum)
{
    data[7] = (hum/10);
    data[6] |= (hum - data[7]*10) << 4;
}
 
/**
 * \brief    Set the sensor temperature
 * \param    data       Oregon message
 * \param    temp       the temperature
 */
void setPressure(byte *data, float pres) 
{
  if ((pres > 850) && (pres < 1100)) {
    data[8] = (int)round(pres) - 856;
    data[9] = 0xC0;  
  }
}
 
/**
 * \brief    Sum data for checksum
 * \param    count      number of bit to sum
 * \param    data       Oregon message
 */
int Sum(byte count, const byte* data)
{
  int s = 0;
 
  for(byte i = 0; i<count;i++)
  {
    s += (data[i]&0xF0) >> 4;
    s += (data[i]&0xF);
  }
 
  if(int(count) != count)
    s += (data[count]&0xF0) >> 4;
 
  return s;
}
 
/**
 * \brief    Calculate checksum
 * \param    data       Oregon message
 */
void calculateAndSetChecksum(byte* data)
{
#if MODE == MODE_0
    int s = ((Sum(6, data) + (data[6]&0xF) - 0xa) & 0xff);
 
    data[6] |=  (s&0x0F) << 4;     data[7] =  (s&0xF0) >> 4;
#elif MODE == MODE_1
    data[8] = ((Sum(8, data) - 0xa) & 0xFF);
#else
    data[10] = ((Sum(10, data) - 0xa) & 0xFF);
#endif
}
 
/******************************************************************/
/******************************************************************/
/******************************************************************/
 
void setup()
{
  pinMode(TX_PIN, OUTPUT);
 
  Serial.begin(9600);
  Serial.println("\n[Oregon V2.1 encoder]");
 
  SEND_LOW();  
  
#if MODE == MODE_0
  // Create the Oregon message for a temperature only sensor (THN132N)
  byte ID[] = {0xEA,0x4C};
#elif MODE == MODE_1
  // Create the Oregon message for a temperature/humidity sensor (THGR2228N)
  byte ID[] = {0x1A,0x2D};
#else
  // Create the Oregon message for a temperature/humidity/barometer sensor (BTHR918N)
  byte ID[] = {0x5A, 0x6D};
#endif
 
  setType(OregonMessageBuffer, ID);
  setChannel(OregonMessageBuffer, 0x20);
  setId(OregonMessageBuffer, 0xCB);
}
 
void loop()
{
  // Get Temperature, humidity and battery level from sensors
  // (ie: 1wire DS18B20 for température, ...)
  setBatteryLevel(OregonMessageBuffer, 1); // 0 : low, 1 : high
  setTemperature(OregonMessageBuffer, 11.2);
 
#if MODE != MODE_0
  // Set Humidity
  setHumidity(OregonMessageBuffer, 52);
#endif  

#if MODE == MODE_2
  // Set Pressure
  setPressure(OregonMessageBuffer, 1013);
#endif  
 
  // Calculate the checksum
  calculateAndSetChecksum(OregonMessageBuffer);
 
  // Show the Oregon Message
  Serial.println("Oregon -> ");
  for (byte i = 0; i < sizeof(OregonMessageBuffer); ++i)   {     
    Serial.print(OregonMessageBuffer[i] >> 4, HEX);
    Serial.print(OregonMessageBuffer[i] & 0x0F, HEX);
  }
  Serial.println();
 
  // Send the Message over RF
  sendOregon(OregonMessageBuffer, sizeof(OregonMessageBuffer));
  // Send a "pause"
  SEND_LOW();
  delayMicroseconds(TWOTIME*8);
  // Send a copie of the first message. The v2.1 protocol send the
  // message two time 
  sendOregon(OregonMessageBuffer, sizeof(OregonMessageBuffer));
 
  // Wait for 30 seconds before send a new message 
  SEND_LOW();
  delay(30000);
}

ciao, many thanks for your work !

I've tried this code with different arduino's board, a nano and uno with a simple tx on 433,920 simulating a common THGR228N.
the problem is that another arduino can receive and decode the simulated transmission but no oregon bases are capable to receive it .
what I wrong ?
I fear going crazy ...

ciao, many thanks for your work !

I've tried this code with different arduino's board, a nano and uno with a simple tx on 433,920 simulating a common THGR228N. the problem is that another arduino can receive and decode the simulated transmission but no oregon bases are capable to receive it . what I wrong ? I fear going crazy ...

Did you solve?

Sorry, this is too old in my memory I don't use this anymore... If you find a solution, please post here for reference!