A interrupt controller includes specialized interfaces and controls for ARM7TDMI-type microcontroller cores. Such a device is connected in series to a MOS transistor of the opposite polarity and such arrangements are cross-connected together to form a latch circuit. When the visor is manually activated to pivot out of an end position, the visor is accelerated by resilient pretensioning in the direction of the other end position until the lip is in contact with the helmet shell substantially without recoil. High-density connectors connect the circuit boards. The clutch engagement controller is configured to receive from the altitude sensor an altitude signal corresponding to the altitude of the vehicle.