Activation system includes a reception device for receiving an activation signal (SIGA), and an activation circuit (4) for activating an electric circuit (5). A pyroelectric element (3) is connected to the reception device (1) and to the activation circuit (4). The pyroelectric element can be heated by the activation signal (SIGA) in such a way that a voltage high enough to actuate the activation circuit (4) is produced in the pyroelectric element.