Nowadays most packaging machines manufacturers implement highly automated sophisticated components to be very costly. Moreover the economic circumferences and agricultural industry revolution in Egypt impose to find local technical solutions for all industrial production obstacles. The approach towards low cost automatic packaging prototype is depending on using simple pneumatic, mechanical, electrical and electronic devices in prototype manufacturing with high productivity concerns. These synergistic combinations of those engineering fields lead to the science of mechatronics. Open sources hardware provides the suitable environment for creation without additional costs. Three innovative embedded systems were designed and virtually simulated using software package Proteus Design Suite 8. The first one is for weighing process by an infrared (transmitter and receiver) and load cell sensors for information gathering to an open source microcontroller (Arduino-Uno). Pneumatic pistons and DC motor were used as control system actuators. The DC motor was used to rotate the conveyor belt with different speeds controlled by the other two designs of embedded control systems, close loop system (phase locked loop technique integrated with pulse width modulation technique) and open loop system (pulse width modulation technique) were analyzed and compared using an oscilloscope for frequency graphing. The conveyor belt velocity was determined based on the information about product weight and the total weight required for packaging. The performance of each unit of the packaging prototype was analyzed. The experimental result of the packaging prototype was capable of fully automate three different types of fruits and vegetables which are lemon (Citrus aurantifolio), tomato Peto 86 (Lycopersicon escalentum-Mill) and ripe plum (Prunes salicina).
Their physical properties; major, intermediate and minor dimensions are 44.8, 42 and 40.17mm, 75.19, 52.6 and 47.6mm and 49.98, 47.533, 42.06mm, respectively. Geometric diameters are 42.29, 57.35 and 46.4mm, respectively. The average sphericity index is 94.4, 76.3 and 92.8%, respectively. Lemon and plum are tending to roll rather than sliding and show high compact arrangement inside the packaging material. Angle of repose of two different types of conveyor belts were tested with the fruits, the highest coefficient of friction is for nodded belt. Under open loop control the rotational speed of the DC geared motor was decreased in the range of 33 to 40% under full load condition; whereas the close loop control system remains the rotational speed constant, but consumes more electrical power of 50 to 55%. The innovative embedded system of close loop control of the DC geared driver motor aids the weighing unit to obtain higher pack weight precision of the tomatoes, plum and lemon due to its higher regularity of conveyor belt velocity to fill the packs with product until one kilogram is achieved. These embedded systems have whole cost of 761.05LE, in comparison with other control systems of 5000 to 30000LE doing the same control work of automation. Further investigations will complete this work to apply this innovative embedded control system at fruits and vegetables packaging plants.