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The system consists of a weighing scale, Reflective IR Sensor, two pneumatic arms and a PIC16F877A microcontroller as the main processing unit. The purpose of the system is to check whether the weight of a package is within the correct weight limit, as defined in the program of the microcontroller, when it enters the weighing scale via a conveyor. So the system is not an in-motion weighing system. If the package is within the correct weight limit the package needs to be pushed into the conveyor where correct weight packages are transported to the desired location in the factory and if the package is more or less than the required weight limit the package is pushed into the conveyor where incorrect weight packages are transported to the preferred part of the factory.
A prototype was developed in a breadboard using the PIC16F877A microcontroller, HIN232CP IC, a button switch to represent the Reflective IR Sensor and two LEDs to represent the two pneumatic arms. The serial input from the weighing scale is modelled by using the computer. The hyper terminal is used to input strings of data to the microcontroller and the data is processed according to the system requirements and serial transmission from the microcontroller to the computer is one of the ways in which the system was tested.
Literature Review
Most of the check weigher machines available commercially come as a complete set (with the weighing scale, user interface, conveyor, etc.) with other modules like metal detectors, open-flap detection, bar-code scanners, etc. integrated onto it and most of the machines built are typically built to suit the particular application in an industrial environment (from Mettler Toledo). These systems are expensive and using such a machine in a factory with a low production rate is expensive an inefficient. So the requirement for such factories is a simple and cheap weighing system. The system proposed systems is a simple check weighs system and the system can be easily integrated with the existing conveyors since the setup is simple as shown in Figure 2 in proposed system section.