CHAPTER ONE

INTRODUCTION

1.1    BACKGROUND TO THE STUDY

In our society today writing a project is all about applying the theories  learnt over the year to produce design and construct and operating system which will be capable of performing a known task. It is from this point of view that we decided to write, design and construct this particular project which has the titles construction and design of distance proximity sensor using LDR and LEDs used in controlling the current flow in the circuit system. Sensors are devices used to provide information on the presence or absence of an object. It measures the closeness of body to obstacles (both animate and inanimate) that may not be visible to the driver or that the driver may yet not have realized (NEMA, 2013).

Previous researcher has discussed the proximity issue in construction including injury and fatality statistics of collisions between construction equipment and workers. Because construction projects often involve many repetitive tasks, construction workers can experience decreased awareness and loss of focus (Pratt et al. 2001, Teizer et al. 2010). Construction equipment operator visibility, specifically operator blind spots, can be a major factor in contact collisions between construction equipment and ground workers (Fullerton et al. 2009). A real-time proximity detection and warning system is needed on construction jobsites to warn equipment operators of hazardous proximity situations.

1.2   STATEMENT OF THE PROBLEMS

The problem statements regarding this project are:

Ø The usage sensors of are on the rise from time to time but there are no cheaper design that is constructed to detect object (animate and inanimate at closed proximity.

Ø The most common type of proximity sensor is the infrared, ultrasonic types and when they are faulty component are rare to see in the market.

Ø An alternate method of designing distance proximity sensors needs to be developed to curb the scarcity of electronics for measuring distance.

Ø Scientific laboratory experiment are carried out without safety awareness, safety consciousness has to be improved in schools laboratories.

1.3   AIM AND OBJECTIVE OF THE PROJECT  

The aim and objective of this project is to highlight and construct a distance proximity sensor using Light Dependent Resistor (L.D.R). Proximity sensors have been constructed in many different ways but this Light dependent resistors type is more sensitive than inductive and capacitive sensors which are rarely used in circuit designs. This is because it is a photocell that works on the principle of photoconductivity whose resistance value decreases when light intensity of light decreases. Light dependent resistors are also called optoelectronic devices when exposed to source of light with high intensity will automatically lights up the light emitting diodes.

1.4  SCOPE OF THE PROJECT

Proximity sensors comes in various design voltages and ohms the choice of a particular sensor then depends on its function either for construction of automatic street light circuit, simple fire alarm circuit, light activated circuit,, automated LED emergency light and night security light. The project tends to cover the design of distance sensor using light dependent resistors and LED to indicated obstacles at close proximity to the device.

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