sniffing
• http://travisgoodspeed.blogspot.com/2011/02/promiscuity‑is‑nrf24l01s‑duty.html 
• http://goodfet.sourceforge.net/clients/goodfetnrf/ 
Alternative implementation
• http://sarwiki.informatik.hu‑berlin.de/R0ket_Keyboard_sniffer 
• https://github.com/Kaczmarczyck/r0ket/blob/486d3e07b08f185346a41a79e485f2999ddaf2ea/firmware/applications/radi0.c 
Arduino libraries
• https://github.com/aaronds/arduino‑nrf24l01 
• https://github.com/maniacbug/RF24  (has private functions for register access, not suitable for sniffing)
MCU independent
• https://github.com/kehribar/nrf24L01_plus