An electronic device comprising: - a sensor able to detect a predefined event ; - a processing digital circuit connected to the sensor , the processing digital circuit being in an off state; - a power source connected to the sensor , - a switch positioned between the power source and the processing digital circuit ; - -an event detection device connected to the sensor and configured to activate the switch to connect the processing digital circuit to the power source when the sensor detects the predefined event , so as to switch the processing digital circuit from the off state to an on state, wherein the processing digital circuit is configured to read in the on state a signal from the sensor when the sensor detects the predefined event and the processing digital circuit is configured to operate at least a predetermined task when it reads the signal from the sensor , wherein the event detection device is configured to deactivate the switch to disconnect the processing digital circuit from the power source once the at least a predetermined task has been operated, characterized in that said electronic device further comprises a circuitry change device connected to the event detection device and configured to detect a change within the electronic device , send an initiating signal to the event detection device , the event detection device being configured to connect the processing digital circuit to the power source , so as to switch the processing digital circuit from the off state to the on state, and the processing digital circuit being configured to send a configuration signal to the sensor , so as to pair the sensor with the processing digital circuit , wherein the change within the electronic device is a power source change and/or a sensor change and/or a processing digital circuit change. - a sensor able to detect a predefined event ; - a processing digital circuit connected to the sensor , the processing digital circuit being in an off state; - a power source connected to the sensor , - a switch positioned between the power source and the processing digital circuit ; - -an event detection device connected to the sensor and configured to activate the switch to connect the processing digital circuit to the power source when the sensor detects the predefined event , so as to switch the processing digital circuit from the off state to an on state, wherein the processing digital circuit is configured to read in the on state a signal from the sensor when the sensor detects the predefined event and the processing digital circuit is configured to operate at least a predetermined task when it reads the signal from the sensor , wherein the event detection device is configured to deactivate the switch to disconnect the processing digital circuit from the power source once the at least a predetermined task has been operated, characterized in that said electronic device further comprises a circuitry change device connected to the event detection device and configured to detect a change within the electronic device , send an initiating signal to the event detection device , the event detection device being configured to connect the processing digital circuit to the power source , so as to switch the processing digital circuit from the off state to the on state, and the processing digital circuit being configured to send a configuration signal to the sensor , so as to pair the sensor with the processing digital circuit , wherein the change within the electronic device is a power source change and/or a sensor change and/or a processing digital circuit change. <EOS>