There are many devices for preventing a driver from falling asleep. Some of the devices monitor the driver's head position, and send an alert when the driver's head is tilted forward. For example, U.S. Pat. No. 5,684,461 describes a sleep prevention device for a driver of a vehicle. The device is comprised of a head set, a mercury switch, an alarm indicator having a speaker for emitting a vocal alarm, a volume control dial, a light emitting diode, a 12 volt adapter and a flexible pouch. The head set is placed on the head of the driver, and the mercury switch is within a housing that is attached to the headset. The mercury switch senses when the driver's head is tilted forward and thereupon sends an activation signal. A mercury switch has a sealed glass housing. In one end of the housing there are two electrodes. The first electrode is placed at a short distance from the second electrode. Within the housing there is a small amount of mercury. When the driver's head is in a predetermined range of deviation from the horizontal, the mercury moves into contact with the two electrodes and closes an electrical circuit across the electrodes. The activation signal activates the speaker, which emits a vocal alarm. A disadvantage of this device is its complexity and its use of many separate parts. Another disadvantage of this device is the use of a vocal alarm to notify the driver that he is falling asleep. Sending a vocal alarm is not efficient when the driver is in a noisy environment, or when the driver activates a radio, a C.D. player, a tape player or any other apparatus which produces sound and/or noise. A further disadvantage of this device is the need to connect it to an external power supply source.
There is a need for an improved apparatus for preventing a driver from falling asleep, of compact size. There is a need for an improved apparatus for preventing a driver from falling asleep, which is effective even when driver is in a noisy environment, or when the driver activates a radio, a C.D. player, a tape player or any other apparatus which produces sound and/or noise.