Dozing off is the main cause of traffic accident. Setting up the device on user's head at an inclined angle as the sensing core, when user's face below the threshold of inclined angle, the control circuit will produce electrical signal and started up sound, vibration and warning lights to alert user and people around. Thus this invention can effectively prevent driver from dozing and enthusiast bending their head to use consumer electronics too long. The advantage of this invention is small, lightweight, low-cost, high safe and durable. This device no need extra battery because it included rechargeable battery and can be charged by USB socket. It has excellent comfort and convenience. The device combine ??Blue Tooth?? technology, increase it??s applications.