Soundless Horn
Source section
Astable
Multivibrator
•
The TSOP 1738(IR sensor) requires an incident
signal with a centre frequency of 38khz.
•
So the Infra red LED must be illuminated by a
signal that has a frequency of 38khz.
•
This is accomplished by generating the
required signal using an
atable
multivibrator
.
Source section
Advised data format
•
The main intricacy involved with the TSOP
1738 is that a continuous signal of 38khz is
treated as noise.
•
There is a suggested data format of sending IR
pulses to the sensor.
•
They should be in the form of bursts of cycles.
•
The bursts should have 10
-
70 cycles
Data format
(contd.,)
•
There should be a gap of at least 14 cycles
between the bursts.
•
While all these criteria being satisfied, the
frequency of the pulse train must be kept at
38khz.
Monostable
multivbrator
#2
•
As the format consists of bursts, to produce a
burst of cycles the
astable
should be on and
for the gap between the bursts it should be
off.
•
This can be achieved by drawing the
supply(
Vcc
) of the
astable
from the output of
the
monostable
multivibrator
.
Monostable
multivbrator
#2
(contd.,)
•
As there should be 10
-
70 cycles/burst based
on the frequency of the
astable
output signal
its time period can be calculated and hence
the time required for 20 cycles is determined.
•
This becomes the on time of the
monostable
multivibrator
#2.
•
Similarly based on the gap between the bursts
reqiured
the Off time should be adjusted.
Monostable
multivbrator
#1
•
This
multivibrator
forms the initial block of the
source section.
•
A driver while blowing a horn excites this
multivibrator
. This is nothing but the trigger to
the
multivibrator
.
•
It generates a signal that sustains for a
duration of 0.5 sec.
•
This forms the supply of the
monostable
#2.
Source section using Microcontroller
•
The circuit using
multivibrators
is only for
testing purpose
•
For accuracy and to reduce bulkiness, the same
can be implemented using Microcontroller
Enter the password to open this PDF file:
File name:
-
File size:
-
Title:
-
Author:
-
Subject:
-
Keywords:
-
Creation Date:
-
Modification Date:
-
Creator:
-
PDF Producer:
-
PDF Version:
-
Page Count:
-
Preparing document for printing…
0%
Σχόλια 0
Συνδεθείτε για να κοινοποιήσετε σχόλιο