	Temperature Controller

	Liquid Level Controller

	Load Positioning System

	Laser Cutting Machine

	Motion Control System

	DC Motor controller

	AC Motor speed control

~: Load Positioning System :~

Abstract: - some times it is needed that the object should remain inline or in contact with other moving object. for example in satellite tracking system the dish antenna should always point to moving satellite to receive maximum signal. a slight deviation may also reduce the signal strength. in gun barrel position system for military tank or anti-aircraft gun once the target is locked the gun should point to target always till the shell (bomb) is fired to hit the bulls eye. so here we need load positioning system.

in this system there is one moving object. we have to keep the position of this object fix. the reference position of this object is known as set value. if there is any deviation of object from its position due to any reason it will be automatically corrected by moving the object to its reference position.

here there is one fixed end which serves as reference point. the position of moving object is fixed with reference to this point. now as the object deviate from this position in either direction the system will sense it and move the object in opposite direction till it reaches to reference position.

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Mechanical arrangement: -

As shown in figure, on the fix base there is one fix end. The moving platform is coupled with the shaft stepper motor. Pullies and sliding surface is provided to reduce any friction. The circuit is housed in a wooden box that is fixed on moving platform. A light source (high intensity and focused LED) is fixed in to the fix end. A small opening is provided in wooden box for LDR. The motor terminals and LED terminals are connected with the circuit in a box with long wires as shown (A, B, C, D, E, F).

Block Diagram: -

as shown in above figure, the major building blocks of this system are A to D converter (ADC0801), micro controller 89C51 / 51, LCD display panel and driver chip ULN2003.

ADC0801 - when LDR is applied proper bias, and when light falls on it, it converts light energy into equivalent voltage. this voltage is in analog format so ADC will convert it in to digital form and give it to micro controller.

89C51 - this chip is the heart of entire system. it controls complete system by performing following tasks.

reads digital equivalent input form ADC after pre determined time
compares this input with set value (ref. value) and rotate the motor clockwise or anticlockwise to match these two value
displays messages and values LCD panel
give indication on LEDs of various actions

LCD panel - its alphanumeric LCD panel that displays messages and different values set value, ref. value given by 89C51

ULN 2003 - the direct output of micro controller can not drive stepper motor. so to amplify the current of port this chip is used, as it consists of 7 inbuilt Darlington pairs that can sink the current upto 500 mA. so this is enough to drive stepper motor.