Driver drowsiness alarm circuit

The circuit shown is a sleep alarm circuit. Figure a shows an alarm switch composed of a mercury switch
and a plug. The mercury switch is composed of an electrode installed in a glass shell and mercury injected into it. b is the alarm circuit
, which uses the lighting power supply (or battery cabinet j1) on the motorcycle (or car) instead. The alarm sound does
not need earplugs. Instead, it uses HTD
piezoresistive sounding components with feedback electrodes.
    Use At this time, put the part a in Figure 13-12 on the driver
's head and put on the earplug machine. The position of the mercury switch
should be adjusted according to the habitual position of the driver's head
so that the circuit is not connected. When the driver is sleepy,
his head Shake your head or tilt your body to cause
the mercury in the mercury switch to flow, and turn on the mercury switch .
VT will work. HTD will immediately sound an alarm. The sound frequency of this
circuit is 4kHz, which is extremely sensitive to human hearing. Adjust iookfl, resistance, you can Change the volume of the sound.