An acceleration sensor arrangement comprises, in one package, an acceleration threshold detector for detecting acceleration and for providing an output signal and a processor circuit for receiving the output signal. The acceleration threshold detector provides an output signal having a first value when the acceleration is less than a predetermined threshold and is arranged to switch the output signal from the first value to a second value when the acceleration reaches the predetermined threshold. The processor circuit generates an event signal to trigger an event, such as the closing of a safing transistor switch in an airbag system, in response to the output signal from the acceleration threshold detector switching to the second value.