Abstract: The detection device comprises an electrical power reserve, a voltage regulator configured to regulate the voltage supplied by the electrical power reserve, at least one capacitor charged by the voltage regulator, a detection circuit powered by the capacitor and a switch. The switch is configured to deactivate the regulator when the capacitor's charge is greater than a predefined value, such that the detection circuit is then only supplied with electricity by each said capacitor. The switch can be configured to open the circuit comprising the power reserve upstream of the regulator, and the switch comprises a means of comparing the electrical charge of each capacitor with a predefined value and/or the switch comprises a transistor.