NRF24L01

A two-way radio transceiver for microcontroller-to-microcontroller links, offering far better range and lower power than Bluetooth for simple data. Multiple nodes can address each other, making it a practical basis for sensor networks and remote controls. The single most common problem is power: the module draws sharp current spikes and an Arduino's 3.3V pin cannot keep up, causing links that work at a metre then fail. Solder a 10uF capacitor across VCC and GND at the module — this one step fixes the majority of nRF24 complaints. Two-way communication, not just transmit or receive; Better range and lower power than Bluetooth for data; Addressable nodes suit sensor networks; Automatic acknowledgement and retry built in