Simple Input/ Output System using Sound Transducers

There are many different types of transducers available in the marketplace, and the choice of which one to use really depends upon the quantity being measured or controlled.

Input type transducers or sensors, produce a proportional output voltage or signal in response to changes in the quantity that they are measuring (the stimulus) and the type or amount of the output signal depends upon the type of sensor being used. Generally, all types of sensors can be classed as two kinds, passive and active.

Active sensors require some form of external power to operate, called an excitation signal which is used by the sensor to produce the output signal. Active sensors are self-generating devices because their own properties change in response to an external effect and produce an output voltage, for example, 1 to 10v DC or an output current such as 4 to 20mA DC. For example, a strain gauge is a pressure-sensitive resistor. It does not generate any electrical signal, but by passing a current through it (excitation signal), its resistance can be measured by detecting variations in the current and/or voltage across it relating these changes to the amount of strain or force.

Unlike the active sensor, a passive sensor does not need any additional energy source and directly generates an electric signal in response to an external stimulus. For example, a thermocouple or photodiode. Passive sensors are direct sensors which change their physical properties, such as resistance, capacitance or inductance etc. As well as analogue sensors, Digital Sensors produce a discrete output representing a binary number or digit such as a logic level "0" or a logic level "1".

Analogue Sensors produce a continuous output signal or voltage which is generally proportional to the quantity being measured. Physical quantities such as Temperature, Speed, Pressure, Displacement, Strain etc. are all analogue quantities as they tend to be continuous in nature. For example, the temperature of a liquid can be measured using a thermometer or thermocouple which continuously responds to temperature changes as the liquid is heated up or cooled down.

 

3. Translate the word combinations:

To convert energy of one kind into energy of another kind; unlike the active sensor; a pressure-sensitive resistor; physical properties; the amount of strain; an external stimulus; excitation signal; an output function; a wide range of different energy forms; a single light.

 

4. Arrange the following words in pairs of antonyms:

a number of on the other hand

out-of-date regarding

result in some

regardless up-to-date

on the one hand result from

 

5. Define the parts of speech of the following words; translate them into Russian:

To differ – different – indifferent – difference; long – length – to lengthen; to apply – application – applicable – appliance; efficient – inefficient – efficiency; to divide – division – divisible – indivisible; to vary – variety – various – variable – invariable; to transform – transformer – transformation; to convert – converter – conversion – convertible; machine – to machine – machinery – machinable

 

 

6. Form the gerund choosing the following verbs:

To convert; to create; to utilize; to move; to run

1) The idea of (использования) the energy of oceans is not new, but tidal stations are still few. 2) Recently scientists have succeeded in (создать) a few kinds of generators for (превращения) heat directly into light. 3) This machine tool is capable of (работать) at very high speeds. 4) In fact, (превращение) conventional kinds of fuels into electricity is not economic enough. 5) Upon being heated the molecules begin (двигаться) very rapidly.

 

7. Translate into Russian paying attention to the function and the form of gerund:

1) These pieces of metal can’t be used in the process without being hammered into thin sheets. 2) The investigator mentioned his having tested this material for strength. 3) Strengthening metals means reinforcing them with artificial fibers. 4) Their being reinforced with artificial fibers makes them more corrosion resistant. 5) Without having improved the properties of this alloy we couldn’t use it in the production process. 6) Using atomic fuel for the production of electricity is one of the most promising sources of energy. 7) Atomic fuel has great possibilities. Its being used for the direct production of electricity is one of the most promising. 8) Much effort is being given to find the most efficient means of generating electricity. 9) After the young scientist’s report having been discussed at the conference it was published in a scientific journal. 10) Sometimes we speak of applying a still broader definition of communication including the influence of one mechanism upon another mechanism. 11) Our having mastered a foreign language helps us in our work.

 

8. Define the group of subject:

1) Testing engines should be carried out on a special stand.

2) The increasing pressure was measured precisely.

3) The metals to be strengthened are subjected to special operations.

4) The pressure increased was measured precisely.

5) To operate new flexible line became possible thanks to computers.

 

9. Define the group of the predicate:

1) Scientists are doing their best to find more efficient ways of utilizing solar energy.

2) The task of the computer is to operate the whole line properly.

3) When transported gases are compressed into strong cylinders.

4) While discussing the design the engineers suggested a few improvements.

 

10. Translate the texts into Russian without a dictionary and write down the main idea of each following texts:

 

Data acquisition

 

Data acquisition is the process of sampling signals that measure real world physical conditions and converting the resulting samples into digital numeric values that can be manipulated by a computer. Data acquisition systems (abbreviated with the acronym DAS or DAQ) typically convert analog waveforms into digital values for processing. The components of data acquisition systems include:

- Sensors that convert physical parameters to electrical signals.

- Signal conditioning circuitry to convert sensor signals into a form that can be converted to digital values.

- Analog-to-digital converters, which convert conditioned sensor signals to digital values.

Data acquisition applications are controlled by software programs developed using various general purpose programming languages such as BASIC, C, Fortran, Java, Lisp, Pascal.

Specialized software tools used for building large-scale data acquisition systems include EPICS. Graphical programming environments include ladder logic, Visual C++, Visual Basic, and Lab VIEW.

 

Methodology

Source

Data acquisition begins with the physical phenomenon or physical property to be measured. Examples of this include temperature, light intensity, gas pressure, fluid flow, and force. Regardless of the type of physical property to be measured, the physical state that is to be measured must first be transformed into a unified form that can be sampled by a data acquisition system. The task of performing such transformations falls on devices called sensors.

A sensor, which is a type of transducer, is a device that converts a physical property into a corresponding electrical signal (e.g., a voltage or current) or, in many cases, into a corresponding electrical characteristic (e.g., resistance or capacitance) that can easily be converted to an electrical signal.

The ability of a data acquisition system to measure differing properties depends on having sensors that are suited to detect the various properties to be measured. There are specific sensors for many different applications. DAQ systems also employ various signal conditioning techniques to adequately modify various electrical signals into voltage that can then be digitized using an Analog-to-digital converter (ADC).

Signals

Signals may be digital (also called logic signals sometimes) or analog depending on the transducer used.

Signal conditioning may be necessary if the signal from the transducer is not suitable for the DAQ hardware being used. The signal may need to be amplified, filtered or demodulated. Various other examples of signal conditioning might be bridge completion, providing current or voltage excitation to the sensor, isolation, and linearization. For transmission purposes, single ended analog signals, which are more susceptible to noise, can be converted to differential signals. Once digitized, the signal can be encoded to reduce and correct transmission errors.

 

DAQ hardware

DAQ hardware is what usually interfaces between the signal and a PC. It could be in the form of modules that can be connected to the computer's ports (parallel, serial, USB, etc.) or cards connected to slots (S-100 bus, Apple Bus, ISA, MCA, PCI, PCI-E, etc.) in the motherboard. Usually the space on the back of a PCI card is too small for all the connections needed, so an external breakout box is required. The cable between this box and the PC can be expensive due to the many wires, and the required shielding.

DAQ cards often contain multiple components (multiplexer, ADC, DAC, TTL-IO, high speed timers, RAM). These are accessible via a bus by a microcontroller, which can run small programs. A controller is more flexible than a hard wired logic, yet cheaper than a CPU so that it is permissible to block it with simple polling loops. For example: Waiting for a trigger, starting the ADC, looking up the time, waiting for the ADC to finish, move value to RAM, switch multiplexer, get TTL input, let DAC proceed with voltage ramp. Many times reconfigurable logic is used to achieve high speed for specific tasks and digital signal processors are used after the data has been acquired to obtain some results. The fixed connection with the PC allows for comfortable compilation and debugging. Using an external housing a modular design with slots in a bus can grow with the needs of the user.

Not all DAQ hardware has to run permanently connected to a PC, for example intelligent stand-alone loggers and oscilloscopes, which can be operated from a PC, yet they can operate completely independent of the PC.

 

DAQ software

DAQ software is needed in order for the DAQ hardware to work with a PC. The device driver performs low-level register writes and reads on the hardware, while exposing a standard API for developing user applications. A standard API such as COMEDI allows the same user applications to run on different operating systems, e.g. a user application that runs on Windows will also run on Linux.

 

11. Translate into English, write down the main idea of the text first in Russian, then in English: