I have a HC-SR04 Distance Sensor plugged into my ez-b (or some other device that needs both digital input and output). I want to unplug the connecting digital wires, and in their place, send the digital signals via some kind of RF transceiver. So there would be one module connected to the ez-b, and other connected to the HC-SR04 Distance Sensor, simply performing the function of the two digital wires. Preferably the transceiver should act like a "blackbox" i.e. acts the same as the two digital cables without any extra programming required.
Does such a thing exist? What's the cheapest version of it?