Ultrasonic switch Chapter-1 Introduction 1.1 Introduction Circuit of a new type of remote control switch is described here. This circuit functions with inaudible (ultrasonic) sound. Sound of frequency up to 20 kHz is audible to human beings. The sound of frequency above 20 kHz is called ultrasonic sound. The circuit described generates (transmits) ultrasonic sound of frequency between 40 and 50 kHz. As with any other remote control system this cirucit too comprises a mini transmitter and a receiver circuit. Transmitter generates ultrasonic sound and the receiver senses ultrasonic sound from the transmitter and switches on a relay. The ultrasonic transmitter uses a 555 based astable multivibrator. It oscillates at a frequency of 40-50 kHz. An ultrasonic transmitter transducer is used here to transmit ultrasonic sound very effectively. The transmitter is powered from a 9-volt PP3 single cell. The ultrasonic receiver circuit uses an ultrasonic receiver transducer to sense ultrasonic signals. It also uses a two-stage amplifier, a rectifier stage, and an operational amplifier in inverting mode. Output of op-amp is connected to a relay through a complimentary relay driver stage. A 9-volt battery eliminator can be used for receiver circuit, if required. Ultrasonic sensors (also known as transceivers when they both send and receive) work on a principle similar to radar or sonar which evaluate attributes of a target by interpreting the echoes from radio or sound waves respectively. Ultrasonic sensors generate high frequency sound waves and evaluate the echo which is received back by the sensor. Sensors calculate the time interval between sending the signal and Department of E.C.E. Mandsaur Institute of Technology 1
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Ultrasonic switchChapter-1
Introduction
1.1 Introduction
Circuit of a new type of remote control switch is described here. This circuit functions with inaudible
(ultrasonic) sound. Sound of frequency up to 20 kHz is audible to human beings. The sound of frequency
above 20 kHz is called ultrasonic sound. The circuit described generates (transmits) ultrasonic sound of
frequency between 40 and 50 kHz. As with any other remote control system this cirucit too comprises a mini
transmitter and a receiver circuit. Transmitter generates ultrasonic sound and the receiver senses ultrasonic
sound from the transmitter and switches on a relay. The ultrasonic transmitter uses a 555 based astable
multivibrator. It oscillates at a frequency of 40-50 kHz. An ultrasonic transmitter transducer is used here to
transmit ultrasonic sound very effectively. The transmitter is powered from a 9-volt PP3 single cell. The
ultrasonic receiver circuit uses an ultrasonic receiver transducer to sense ultrasonic signals. It also uses a
two-stage amplifier, a rectifier stage, and an operational amplifier in inverting mode. Output of op-amp is
connected to a relay through a complimentary relay driver stage. A 9-volt battery eliminator can be used for
receiver circuit, if required.
Ultrasonic sensors (also known as transceivers when they both send and receive) work on a principle
similar to radar or sonar which evaluate attributes of a target by interpreting the echoes from radio or sound
waves respectively. Ultrasonic sensors generate high frequency sound waves and evaluate the echo which is
received back by the sensor. Sensors calculate the time interval between sending the signal and receiving the
echo to determine the distance to an object.Because they are not hard to understand and interfacing them is
easy, ultrasonic sensors are commonly used in robotics. The sensor works in the following ways: A sonic
pulse is emitted from the sensor, then when the pulse bounces off of an object, an echo is returned. The
sensor is able to emit the pulse because of a transducer that converts between sonic, electrical and
mechanical energies.
There are two types of transducers commonly used. The first is called a piezo, and the second is an
electrostatic transducer. Distance is calculated by measuring the time from which the pulse is sent to the
time that the echo is returned.
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Ultrasonic switch1.2 Literature Survey
The present invention relates to a switch module, and more particularly to a wireless switch module, which
can be switch "On" and "Off" via a mechanical means or a wireless digital control signal. In the daily life,
for controlling electrical apparatus or electronic devices on and off, a switch assembly is usually provided to
be coupled with electrical apparatus and the electronic devices, so that a user can operate a switch button
connected to the switch assembly to switch-control electrical apparatus and the electronic devices "On" and
"Off". Due to that there are three problems existing in the prior arts, such as the switch assembly cannot
meet the requirements of wireless control, the wireless switch assembly cannot spatially compatible to the
existed frame and the covering board, and the wireless switch assembly is easier to be blind triggered, the
primary objective of the present invention provides a wireless switch module, which can be switch-
controlled either via a mechanical means, or via a wireless digital control signal. Moreover, in spatial, the
wireless switch module is compatible to the existed frame and the covering board, so as to directly replace
the switch cell(s). The secondary objective of the present invention provides a wireless switch module
comprising a micro control circuit, so as to receive and analyze a wireless digital control signal to
accordingly switch-control the switch circuit.
Another objective of the present invention provides a wireless switch module comprising a wireless signal
transceiver. When a wireless digital control signal cannot be effectively received by a wireless module
located in a remote end, the wireless digital control signal can be received and transmitted by other wireless
switch modules, so as to indirectly transmit the wireless digital control signal to the wireless switch module
located in the remote end. Means of the present invention for solving the problems as mentioned above
provides a wireless switch module being fitted with a frame and a covering board, so as to form a wireless
switch assembly. The wireless switch module comprises at least one switch cell and a control unit. The
switch cell comprises a switch circuit, a switch button and a relay, and the control unit comprises a micro
control circuit coupling with the relay. Within the wireless switch module, the switch button is applied to
switch-control the switch circuit "On" and "Off"; furthermore, the micro control circuit is also applied to
switch-control the switch circuit "On" and "Off" via the relay after receiving and analyzing a wireless digital
control signal. In the preferred embodiment of the present invention, the micro control circuit further
comprises a wireless signal transceiver. Comparing with the conventional switch assembly, the wireless
switch modules as provided in the present invention can be switch-controlled both via the switch button(s)
and the wireless digital control signal; therefore, the present invention can meet the requirement of wireless
control.
Comparing with the existed wireless switch assembly, the wireless switch modules as provided in the
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Ultrasonic switchpresent invention can be directly connected to the existed frame and the covering board, and can be further
electrically connected to a power source and at least one loading via at least one power-in wire and power-
out wire. Therefore, both in spatial and electrical, the wireless switch module is compatible to the existed
frame, covering board, power-in wire(s), power-out wire(s), so that the wireless switch module can directly
replace the conventional switch cell(s). In the present invention, except for receiving the wireless digital
control signal, it is still necessary for the wireless switch module to execute a digital analysis to the wireless
digital control signal, and then switch-control the switch circuit "On" and "Off" in accordance with the
analysis result. Thus, the wireless switch module of the present invention can effectively prevent from being
blind triggered by external wireless interference signals. Nevertheless, in the preferred embodiment of the
present invention, the micro control circuit further comprises a wireless signal transceiver. When a wireless
digital control signal cannot be effectively received by a wireless module located in a remote end, the
wireless digital control signal can be received and transmitted by other wireless switch modules, so as to
indirectly transmit the wireless digital control signal to the wireless switch module located in the remote
end. Therefore, it is obviously that the art of the present invention can control the wireless switch module
located in the remote end via the indirectly transmission method.
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Ultrasonic switch
Chapter-2Objective of study
2.1 Components Details/Description
2.1.1 Resistor
A resistor is a two-terminal passive electronic component which implements electrical resistance as a circuit
element. When a voltage V is applied across the terminals of a resistor, a current I will flow through the
resistor in direct proportion to that voltage. The reciprocal of the constant of proportionality is known as the
resistance R, since, with a given voltage V, a larger value of R further "resists" the flow of current I as given
by Ohm's law:
Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in most
electronic equipment. Practical resistors can be made of various compounds and films, as well as resistance
wire (wire made of a high-resistivity alloy, such as nickel-chrome). Resistors are also implemented within
integrated circuits, particularly analog devices, and can also be integrated into hybrid and printed circuits.
We used resistors of various values listed below-
1. Two resistors of 4.7k.
2. Two resistors of 220k.
Department of E.C.E.Mandsaur Institute of Technology