Very easy to build arduino wireless laser turret, also very cheap components you can buy on ebay for example.
To make this project I used 2.4GHz RF transceiver modules that is built in the nRF24L01+ IC.
nRF24L01+ are extremely cheap and cost a few dollars for one piece.
List of components you need to buil this awesome project:
Arduino UNO (only as programmer)
Arduino Pro MINI ---------------2pcs
Breadboard 830 Tie-points
Breadboard 170 Tie-points
Servo 9g -------2pcs
nRF24L01+ module ------ 2pcs
Cellphone Li-ion battery 3.7V -----2pcs
male-to-male cables, male-to-female cables,female-to-female cables