Radio modules are great for interfacing remote objects without need of wires. They are cheap and fairly easy to use. With Arduino things are even better as there are software libraries already ready for use. Rayshobby went even further. They designed a small board that incorporates Atmega328p with Arduino bootloader. 128X64 OLED display, coin cell battery, few navigation buttons and most importantly headers for plugging in various RF modules. In fact normally you would need two types of modules – nRF24L01 that comes with both receiver and transmitter, and two different four pin modules that work in 433/315Mhz frequencies.
Each board works as standalone device that can be paired with other and so creating virtual wires. Few demos demonstrate how they can be used as RF recorder storing 7different signals or controlling 7 different devices. Another use is so popular wireless temperature sensor where remote sensor temperature can be displayed on receiver’s OLED display. Modules are also equipped with 3.5mm audio jack that gives ability to record and analyze RF raw RF signals wit software like Audacity.