DESIGN AND CONSTRUCTION OF A WIRELESS TEMPERATURE TELEMETRY DEVICE
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND
Temperature has been discovered to be the second most measured physical quantity, time
been the First. This shows the need to measure temperature is very necessary, the
measurement thus has to be efficient and convenient.
Years back, crude methods were used in measurement of temperature of objects, colours
and hotness of materials were used in temperature measurement for example colour red
i.e., redness of material means it is hot. But this was not enough to measure the degree of
hotness especially when you need to heat a particular material to a certain temperature.
The need to assign values to temperature measurement led to the invention of the
conventional mercury thermometer, though this method was widely accepted then, it was
indirect and measurement was prone to errors.
The need for accuracy and precision in measurement led to the digital thermometer,
which is more accurate and helps eliminate parallax error during measurement. In this
information era where the wired and wireless technology applications is widely used by
lots of industries and hobbyists, group of experts make a research on how to implement
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the use of these technologies in monitoring the temperature in a more precise and reliable
way.
Telemetry can be described as a highly automated communications process that involves
the collection of measurements and other data at remote or inaccessible points prior to
transmission to receiving equipment for monitoring and control purposes. The word
telemetry is usually associated with wireless methods.
Temperature telemetry is therefore the measurement of temperature of substances, things,
physically inaccessible locations, and transferring the measured temperature value to a
desired or more accessible location.
1.2 OVERVIEW OF THE PROJECT WORK
As we know, radio frequencies refer to the frequencies that fall within the
electromagnetic spectrum associated with radio wave propagation. When applied to an
antenna, RF current creates electromagnetic fields that propagate the applied signal
through space. Any RF field has a wavelength that is inversely proportional to the
frequency and this means that the frequency of an RF signal is inversely proportional to
the wavelength of the field.
It goes the same with this project that used the application of radio frequencies by using
RF transmitter and RF receiver to monitor the temperature of object under test.
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The temperature of the object under test is sensed by an analogue temperature sensor IC
(LM35DZ) and temperature is converted into equivalent voltage (which is about
0.01V/ËšC) by the IC and it is in turn sent to the programmed ATMEGA328
microprocessor which processes the signal data and sends it to the remote end through the
RF transmitter. At the remote end, the RF receiver collects the data and converts it into
equivalent voltage and sends it to the programmed ATMEGA328 at the receiver side
which does the analogue to digital conversion (ADC conversion), and the digital signal is
sent to the Liquid Crystal Display (LCD) for measurement display.
