The Honeywell HIH6130 relative humidity and temperature sensor is a low-cost RHT probe that can easily be added to any electronics application. It operates on I2C, making it easy to add to even the smallest project! Since it is only available in a not-so-fun SOIC-8 package type, I have designed a breakout board that can be found/ordered through Upverter.

How does it compare to other sensors?

This sensor is a little bit more expensive than the DHT22 that is commonly found through Sparkfun, but is supposed to be much more reliable. I will certainly update once I have used it in the field and run calibrations. The graphs will magically appear when I have time!

Existing code?

I could not find a library for this sensor online, so I decided to write my very first Arduino library. It probably isn't pretty (yet), but it gets the job done. Please use the library and board in your projects; I would love to know if you do. These are the things us grad-students live for, I think!

Using the library is easy!

Follow these steps:

  1. Install the library from the GitHub repository
  2. Include the library in your sketch via #include <HIH6130.h>
  3. Initiate an instance of the HIH6130 sensor
  4. Read the data to local variables using rht.readRHT()
  5. Access the data via the public variables humidity and temperature

Sample sketch

#include <Wire.h>
#include <HIH6130.h>

// define the address used by the HIH6130 sensor (default is 0x27)
byte address = 0x27;

// set up an instance of the sensor
HIH6130 rht(address);

void setup(){
  Serial.println("RH\tTemperature (C)");

void loop(){
  // Read the data -> stored to public variables

  // Access and print the variables to the serial monitor
  Serial.print(rht.humidity); Serial.print("\t");

Note: I would love help improving the library and board. Please fork the projects and improve them!