@Terence-Faul

Yes, I have two of them. They are working very well, on 5V as on 3.3V. These are my favorite pro mini clones. :)

Hi,

I've tried the new humidity/temperature sensor HTU21D from sparkfun and really like this little breakout board.
It is a much better replacement for the slow und sometimes unreliable DHTxx sensors. Because of the I2C interface wiring and programming is very easy.

Here is my adapted version of the MySensors humidity sketch (you need the HTU21D library from sparkfun):

#include <SPI.h>                                                                                                                                                            
#include <MySensor.h>                                                                                                                                                       
#include <Wire.h>                                                                                                                                                           
#include <HTU21D.h>                                                                                                                                                         

#define CHILD_ID_HUM 0                                                                                                                                                      
#define CHILD_ID_TEMP 1                                                                                                                                                     
unsigned long SLEEP_TIME = 60000; // Sleep time between reads (in milliseconds)                                                                                             
                                                                                                                                                                        
MySensor gw;                                                                                                                                                                
                                                                                                                                                                        
//Create an instance of the object                                                                                                                                          
HTU21D myHumidity;                                                                                                                                                          
                                                                                                                                                                        
boolean metric = true;                                                                                                                                                      
MyMessage msgHum(CHILD_ID_HUM, V_HUM);                                                                                                                                      
MyMessage msgTemp(CHILD_ID_TEMP, V_TEMP);                                                                                                                                   
                                                                                                                                                                        
void setup()                                                                                                                                                                
{                                                                                                                                                                           
  gw.begin();                                                                                                                                                               
                                                                                                                                                                        
  // Send the Sketch Version Information to the Gateway                                                                                                                     
  gw.sendSketchInfo("Humidity", "2.0");                                                                                                                                     
                                                                                                                                                                        
  // Register all sensors to gw (they will be created as child devices)                                                                                                     
  gw.present(CHILD_ID_HUM, S_HUM);                                                                                                                                          
  gw.present(CHILD_ID_TEMP, S_TEMP);                                                                                                                                        

  metric = gw.getConfig().isMetric;                                                                                                                                         
  myHumidity.begin();                                                                                                                                                       
}                                                                                                                                                                           
void loop()                                                                                                                                                                 
{                                                                                                                                                                           
  float temperature = myHumidity.readTemperature();                                                                                                                         
  if (!metric) {                                                                                                                                                            
      temperature = (temperature * 1.8) + 32.0;                                                                                                                             
  }                                                                                                                                                                         
  gw.send(msgTemp.set(temperature, 1));                                                                                                                                     

  float humidity = myHumidity.readHumidity();                                                                                                                               
  gw.send(msgHum.set(humidity, 1));                                                                                                                                         
                                                                                                                                                                        
  gw.sleep(SLEEP_TIME); //sleep a bit                                                                                                                                       
}

cheers