RFM12B library
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Latest commit b1ff989 Apr 5, 2018


NOTE: not actively maintained

This library is not actively maintained anymore but is kept for reference and can still be used with RFM12b transceivers.

RFM12B Library

By Felix Rusu (felix@lowpowerlab.com)
Based on the RFM12 driver from jeelabs.com (2009-02-09 jc@wippler.nl)


  • easy API with a few simple functions for basic usage
  • 127 possible nodes on 256 possible networks
  • 128 bytes max message length
  • customizable transmit power (8 levels) for low-power transmission control
  • customizable air-Kbps rate allows fine tuning the transmission reliability vs speed (transmitting slower is more reliable but takes more time which implies more power usage)
  • Sleep/Wakeup functionality for power saving
  • Low battery detector with customizable low voltage threshold
  • Interrupt driven
  • Support for targeted ACK instead of broadcasted ACK (possible because of the new source byte in the header) encryption with XXTEA algorithm by David Wheeler, adapted from http://en.wikipedia.org/wiki/XXTEA Support for these chips: ATMega8 family (ATmega168, ATMega328) ATMega2560, ATMega1280, ATMega644P, ATTiny84, ATTiny44, ATMega32u4. So far only tested on ATMega 328/P
  • wireless programming (for more info click here, here and here)
  • the library needed for wireless programming is now here, install it in your Arduino/libraries folder (WirelessHEX for RFM12B)


Copy the content of this library in the "Arduino/libraries/RFM12B" folder.
To find your Arduino folder go to File>Preferences in the Arduino IDE.
See this tutorial on Arduino libraries.

Saple usage

TODOs (in order of priority):

  • Support automatic ACK handling
  • Refactor changing the SPI CS signal
  • Add support for hosting multiple radios on 1 MCU