An Eye Blink sensor is designed as an excellent device for drivers ensuring road safety. This Eye blink sensor continuously monitors eye movements, which will be helpful in warning drivers when they fall asleep. The IR sensor will sense the eye blinking continuously. In this sensor, the normal eye blink has no effect on the output of the system. In case, if the driver fell asleep, then the IR sensor receives an abnormal blinking rate. As a result, an alarm will ring to wake him/her.
Here the sensor part of the Eye Blinking system is designed as a goggle. The variation across the eye will vary as per eye blink. If the eye closes, the output switches to high else the output remain low. Here we use a CNY 70 IR transmitter. This CNY 70 IR is a reflective sensor consisting of an infrared emitter and phototransistor manufactured in a lead package. Thereby it blocks the visible light. The most important thing to be considered is that the IR transmitter and receiver should be in a straight line for optimum performance. The transmitter transmits the IR rays into the eye of the driver.
Depending on whether the eye is closed or open, there will be high output for closed eyes and low output for open eyes. Thus the receiver photodiode receives the transmitted signal. And is further connected to the comparator where it compares the received input signal with the reference signal. The output of the comparator depends on the intensity of light received by the photodiode. Finally, the comparator output fed to the microcontroller decides whether to sound the buzzer or not. The status of the operation is displayed on the LCD, which is connected to the microcontroller. As the output of the microcontroller is low to drive the buzzer, a driver IC is used to amplify the output of the microcontroller.