In this week my research is
about how to test the ultrasonic sensor that I have bought before.
I had met with my
Co-supervisor mdm.Norhayati and we have discussed about the sensor and we come
out with that I have to find some schematic diagram so we can follow it and
after that we construct and test the sensor.
I have done some research and
I found the simplest and some explanation about it.
As I mentioned before in
week 6 ,that the ultrasonic sensor (RK1089) contains of transmitter (T) and receiver
(R) and each one of them have a different circuit.
For the transmitter circuit:
 |
| Figure 1. Schematic Diagram for an Ultrasonic Transmitter Circuit (capacitor values are in microF) |
This circuit is
used to transmit ultrasonic waves through air, which are intended to be picked
up by a matching ultrasonic
receiver.
The circuit uses a
555 timer IC configured as an a stable multi vibrator,
i.e., it generates a continuous signal of a set frequency as long as its reset
pin (pin 4) is held high.
Since the ultrasonic
transducer used in this circuit is one designed to vibrate optimally at about
40 kHz, the resistor and capacitor values of the circuit were chosen such that
the 555 will output a signal whose frequency is about 40 kHz. This 555 output
is amplified by Q1, which drives the ultrasonic transducer. The
transducer then vibrates at 40 Khz, generating ultrasonic sound waves of that
frequency.
If paired with a
matching ultrasonic
receiver, such a simple transmitter can be used as a proximity
sensor, such as one that can help a robot avoid running into walls. If
used in that manner, the transmitter and receiver transducers must be
positioned such that the receiver will only receive echoes of the transmitted
signal and not the transmitted signal itself.
For the receiver circuit:
 |
| Figure 2. Schematic Diagram for an Ultrasonic Receiver Circuit (capacitor values are in microF) |
This circuit is
used to receive ultrasonic waves from the air that were transmitted by a
matching ultrasonic
transmitter located somewhere else.
Since the
ultrasonic receiver used in this circuit is one designed to vibrate optimally
at about 40 kHz, the transmitter paired with this receiver must also transmit
40 kHz waves. When these waves hit the receiver, the receiver vibrates and
produces electric impulses, also at 40 kHz. These electric signals are
amplified by the two op amps in the circuit, the amplified output of which are
fed into the 567 IC. This is a PLL tone decoder, i.e., it outputs a
signal if it detects an input that is tuned to its set frequency (40 kHz in
this case).
One example of
application of this simple receiver (if paired with a matching transmitter,
that is) is as a proximity sensor, such as one that can help a robot avoid
running into walls. If used in that manner, the transmitter and receiver
transducers must be positioned such that the receiver will only receive echoes
of the transmitted signal and not the transmitted signal itself.
And I also found this video
very helpful
-->> Citation:http://www.youtube.com/watch?v=40amNG6heVo&feature=fvsr
Posts
0 comments:
Post a Comment