The present invention relates to a sleep alert device that acts by pressure of the fingers of the user on sensors. The invention includes a limited number of sensors as well as an instant alarm system which prevents accidental problems with previous delay alarm systems. At least one sensor is mounted on the fingers of the user or the steering wheel and with no delay of any kind connected directly or wirelessly to a control panel for control of the pressure sensors. The device has a means for detecting the wearing by the user, such as a pulse detector which can tell if the device is on or off when a pulse is detected respectively.