Arduino shield that allows to activate a relay output with a trasponder. Ideal to control an electric lock, a gate, etc.. Two LED (Red, Green) could be managed independently, a buzzer controlled directly from the Arduino board (pin 3/PWM0) or from ID-12 module. The heart of the shield is of the module ID-12 form Innovations Technology, a component that integrates the generator for the electromagnetic field (need to read the trasponder), the logical circuit to read the card code and the field coil.