Alcohol Detection + RF Feedback

Anti-collision Vehicle




  • Aim and hardware used
  • Overview of the project
  • Block diagram
  • Ultrasonic Piezoceramic Transducer
  • Relay Circuit
  • Block diagram of relay circuit
  • Working of complete circuit
  • Circuit diagram
  • Applications



AIM:- Ultrasonic car  using Ultrasonic sensors



  • Ultrasonic Piezoceramic Transducer Transmitter
  • Ultrasonic Piezoceramic Transducer Receiver
  • Microcontroller
  • AF amplifier
  • CMOS decade counter
  • Op-Amp(IC-741)
  • Frequency divider(IC-4017)
  • Capacitors
  • Resistors
  • Transistors





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.


Relay Circuit:-

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.



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.



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 the driver.


Bill of Material:-


Designator Description Comment Value
89s51 Header, 20-Pin, Dual row Header 20X2
4011 Header, 7-Pin, Dual row Header 7X2A
4069 Header, 7-Pin, Dual row Header 7X2A
BR Full Wave Diode Bridge Bridge1
C1 Capacitor Cap .22
C2 Capacitor Cap .1
C3 Polarized Capacitor (Radial) 35V 1000uF
C4 Polarized Capacitor (Radial) Cap Pol1 470uf
C5 Capacitor Cap .1
C6 Polarized Capacitor (Radial) Cap Pol1 470uf
C7 Capacitor Cap 102
C8 Capacitor Cap .1uf
C9 Capacitor Cap 102
C10 Capacitor Cap 102
C11 Capacitor Cap 102
C16 Capacitor Cap 22pf
C17 Capacitor Cap 22pF
C20 Capacitor Cap .1uf
C27 Polarized Capacitor (Radial) Cap Pol1 10uf
D2 Default Diode 1N4148
D3 Default Diode 1N4148
LCD Header, 16-Pin, Right Angle Header 16H
Q1815 NPN Bipolar Transistor NPN
R1 Resistor Res1 1K
R2 Resistor Res1 1K
R3 Resistor Res1 1M
R4 Resistor Res1 10K
R5 Resistor Res1 10K
R6 Resistor Res1 1K
R7 Resistor Res1 100K
R8 Resistor Res1 1K
R9 Resistor Res1 1K
R10 Resistor Res1 4K7
R11 Resistor Res1 5K6
R15 Resistor Res1 10K
R17 Resistor Res1 10K
R18 Resistor Res1 10K
R19 Resistor Res1 47K
R20 Resistor Res1 47K
Resv1 Tapped Resistor Res Tap 4.7K
RST Switch SW-PB
RV1 Tapped Resistor Res Tap 47K
RV2 Tapped Resistor Res Tap 47K
RX Crystal Oscillator XTAL
S1 Switch SW-PB
S2 Switch SW-PB
SIPR SIP Common Ground Resistor Pack 3k
T1 Transformer (Ideal) Trans Ideal
TX Crystal Oscillator XTAL
U1 4011
U2 4069
U3 Very Low-Noise Quad Operational Amplifier LM324
U4 Very Low-Noise Quad Operational Amplifier LM324
U5 Very Low-Noise Quad Operational Amplifier LM358N
X2 Crystal Oscillator XTAL