MatHertels WebLog: Hints on using NRF24L01+ with Arduino

I like to share some liks to the ressources on the internet that I found helpful for implementing projects using the Ultra low power 2.4GHz RF Transceiver NRF24L01+ with the Arduino platform.

The chip specifications

The NRF24L01 (no + at the end) was replaced by the NRF24L01+ (or sometimes called NRF24L01P). Be sure to get the new chip when buying an breakout board.

The nRF24L01+ is drop-in compatible with nRF24L01 and on-air compatible with nRF2401A, nRF2402, nRF24E1 and nRF24E2. Intermodulation and wideband blocking values in nRF24L01+ are much improved in comparison to the nRF24L01 and the addition of internal filtering to nRF24L01+ has improved the margins for meeting RF regulatory standards.

The old chip: http://www.nordicsemi.com/eng/Products/2.4GHz-RF/nRF24L01

The new chip: http://www.nordicsemi.com/eng/Products/2.4GHz-RF/nRF24L01P

You should read the nRF24L01+DataSheet, even if it is long and with many details – but that’s what you will need: http://www.nordicsemi.com/eng/content/download/2726/34069/file/nRF24L01P_Product_Specification_1_0.pdf

About ShockBurst^TM

This is a nice to read whitepaper with a description of the ShockBurst^TM transfer features of the chip:

http://www.semiconductorstore.com/pdf/NewSite/nordic/WP_nRF240x_ShockBurst.pdf

Arduino compatible Libraries for NRF24L01

There is no official “Arduino” library that is maintained by the core Arduino team so you have to look for the available libraries on the internet.

The web site http://www.tinkerer.eu/ from Stefan Engelke in 2009 provides a native NRF20L01 library, the original MiRF library (not Arduino specific) and a native SPI library See http://www.tinkerer.eu/AVRLib/nRF24L01, and http://www.tinkerer.eu/AVRLib/SPI . I mention this library because it uses interrupts that most Arduino samples don’t.

The MiRF library was ported to the Arduino platform and is using the Arduino SPI library and is described on the arduino playground article: See http://playground.arduino.cc/InterfacingWithHardware/Nrf24L01

J. Coliz (a.k.a. maniacbug) implemented a ARDUINO specific library often called the RF24 library. Its available at https://github.com/maniacbug/RF24/ and was used as the base for implementing other libraries (see below) the last commit to this projects was last on 2012/06/23.

Greg Copeland forked (copied over) the library from maniacbug and added some useful stuff including a scanner sample application. He is currently (2013.04.09) supporting his work. See https://github.com/gcopeland/RF24.

Arco van Geest (a.k.a. gnulnulf) also forked the library from maniacbug is currently adding support for the Raspberry Pi. See https://github.com/gnulnulf/RF24

Stanley Seow forked the version gnulnulf https://github.com/stanleyseow/RF24 also working on upport for the Raspberry Pi.

Critics

There are too much libraries out there for my opinion and those starting from J. Coliz are using the GNU General Public License (not LGPL) and therefore are not compatible with the Arduino license policy.

J. Coliz also used the stdio.h printf() functionality ??? causing more usage of the program memory

For my personal projects I used the library from Greg Copeland for my first steps to discover the functionality of the chip.