International Journal of Research and Reviews in Computer Science (IJRRCS) Vol. 2, No. 6, December 2011, ISSN: 2079-2557 © Science Academy Publisher, United Kingdom www.sciacademypublisher.com 1357 Design and Implementation of a Computer Controlled Fuel Level Monitoring System Afolabi Adeolu and Oke Alice Department of Computer Science and Engineering, Ladoke Akintola University of Technology, Ogbomoso, Nigeria Abstract – This work discussed the design and implementation of a computer controlled fuel level monitoring system. This was achieved by designing a monitoring circuit; this monitoring circuit measures the quantity of fuel inside a fuel tank at four different levels representing four sensors. If the fuel goes below the minimum level, the alarm system embedded in the circuit will be triggered. Anything above this level, the alarm will go off. As the level of fuel increases, it displays on the computer screen when it reaches a particular sensor level. When the fuel level rises to the fourth and final level which represents the maximum, the alarm will be triggered for a while before going off automatically. The monitoring circuit communicates with the computer system with the aid of an interface. A visual basic program is used to interpret the signal being sent from the device and displays the output on the computer screen. Keywords – Implementation, Computer Controlled, Monitoring System 1. Introduction The term fuel is generally limited to those substances that burn readily in air or oxygen, emitting large quantities of heat. Fuels are used for heating, for the production of steam for heating and power purposes, for powering internal- combustion engines, and for a direct source of power in jet and rocket propulsion. Fuel is an important need of a vehicle, without it, the vehicle cannot move. It is an essential of motorist in their everyday activities. The only place where motorist can get the supply of fuel is at the fuel station which makes them being frequently visited by motorist. Due to this, fuel station will have to frequently measure the quantity of their storage tank so as to refill when the fuel in the storage tank is low. The fuel attendant uses a long rod to measure the level of fuel in their storage tank in developing countries. This is a slow and cumbersome process, due to this, there is need to design an automatic system to measure and display the quantity of fuel in the storage tank. This inform our decision to design an automatic fuel level monitoring system that will use a sensor in sensing the level of fuel inside the tanks and interpret it on the computer system in liters. The system will also have an alarm system to indicate when the fuel level in a particular tank is too low, and to trigger a beeping sound when the tank is full. 2. Methodology In this project, we designed a system that will sense the level of fuel in the tank and send it in form of a signal to a computer which is already interfaced with the monitoring system. The computer system will display the level of the fuel both digitally and analog via the aid of a pre coded program, the process is an automatic process.[7] 2.1. LM324 Circuit Description Figure 1.0 Circuit diagram of LM324. Figure 1.0 shows LM324 series is made using four internally compensated, two–stage operational amplifiers. The first stage of each consists of differential input devices Q20 and Q18 with input buffer transistors Q21 and Q17 and the differential to single ended converter Q3 and Q4. The first stage performs not only the first stage gain function but also performs the level shifting and transconductance reduction functions. By reducing the transconductance, a smaller compensation capacitor (only 5.0 pF) can be employed, thus saving chip area. The transconductance reduction is accomplished by splitting the collectors of Q20 and Q18. Another feature of this input stage is that the input common mode range can include the negative supply or ground, in single supply operation, without saturating either the input devices or the differential to single–ended converter. The second stage consists of a standard current source load amplifier stage.