In this project we are using ultrasonic sensors for measuring distance from object. Advantage of using ultrasonic sensor’s is we car use in car to check object distance from car. It should be in cars. In this car we will use two motors . we will control motors using microcontroller 89s52. we will get signal from ultrasonic sensors and will display on LCD 16*2.
We will use port 0 for LCD display.
We will use DC geared 12v motors.
We are using 40kHz frequency Transmitter and receiver.
We will transmit data from transmitter then will amplify using opamp circuits. After amplification we will give signal to
Signal detector. We will use IN4148 diode for decoding purpose.
Or schottky dipde In 5819 .
We will then give signal to comparator circuit,
After comparing we will give signal to microntroller.
Microcontroller will get pulse at pin 2 and transmit at pin 3.
Ultrasonic Piezoceramic Transducer:-
Ultrasonic sensors typically have a piezoelectric ceramic transducer that converts an exciting electrical signal into ultrasonic energy bursts. The energy bursts travel from the ultrasonic sensor, bounce off objects, and are returned towards the sensor as echoes. Transducers are devices that convert electrical energy to mechanical energy, or vice versa. The transducer converts received echoes into analog electrical signals and produces it as output. Ultrasonic transducers operate to radiate ultrasonic waves through a medium such as air.
Humans can hear sound of up to 20 kHz frequency only. This proximity detector works at a frequency of 40 kHz. It uses two specially made ultrasonic transducers: One transducer emits 40 kHz sound, while the other receives 40 kHz sound and converts it into electrical variations of the same frequency with the help of relay circuit.
WORKING OF COMPLETE CIRCUIT:-
The 40 kHz oscillator is built around transistors T1 (BC547) and T2 (BC547). If there is a solid object in front of the ultra- sonic transmitter module (TX1), some signals will be reflected back and sensed by the receiver transducer (RX1). The 40 kHz ultrasonic signals are converted into 40 kHz electrical signals by the receiver and then amplified by transistors T3 (BC549) and T4 (BC558).
The amplified signal is still in the inaudible range, i.e., these can’t be heard. So a frequency-divider stage using CMOS decade counter IC-4017 (IC1) is used at the output of the amplifier. IC1 (4017) divides the input frequency by ‘10’, so the 40 kHz signal becomes 4 kHz, which is within the audible range. The 4kHz signals are then fed to op-amp IC-741 (IC2), which is wired either to an earphone amplifier or microcontroller.
Tx1 = Ultrasonic Transducer Transmitter (40 kHz)
Rx1 = Ultrasonic Transducer Receiver (40 kHz)
becomes 4 kHz, which is within the audible range. The 4kHz signals are then fed to op-amp IC-741 (IC2), which is wired either to an earphone amplifier or microcontroller.
Ø Ultrasonic Piezoceramic Transducer Transmitter
Ø Ultrasonic Piezoceramic Transducer Receiver
Ø AF amplifier
Ø CMOS decade counter
Ø Frequency divider(IC-4017)
1). The circuit can be used as an electronic guard for the blind. Blind persons keep it (along with 9V battery) in their pocket with earphone plugged to their ear. The transducer modules should be directed towards the walking path. If any object comes in front or near by, they will hear 4 kHz sound through the earphone and can change their path accordingly. One thing to be noted here is that while using this device, they have to avoid the company of pets. The reason is that pets can hear ultrasonic sound, which will irritate them and they will bark unnecessarily.
2). It can be used in cars, to help the drivers in backing up and avoid banging against some invisible objects. However, instead of earphones the sound in this case is heard through a speaker and there is also an LCD screen to visually assist t