At my this writing, i will introduce you a transmitter – reciever pack.
I bought this pack for Aliexpress.com . It costs $3.24 for a pack (1 reciever + 1 transmitter)
At the reciver side it has four pins for four channels , 2 pins for power supply (GND – VCC,5V)
and one for antenna.
The transmitter side is an remote control shaped with antenna and four buttons.
I did not made a complex project but i coulnd’t stand without use.
At my experiment I did not connect any external antenna at recivever side
And at the open area it works fine (i tried about 5 meter distances).
But sometimes when i pressed the button, my output led blinks instead of a certain ON state.
i thinks it occurs because of not existance of an external antenna.
I introducd this equipment beacuse it can be useful in your projects.
After this, it depends on your imaginations.