This project is also called “fuel supply system” used to measure & supply exact amount of liquid like water, fuel, carosene, juice, cold-drinks etc. You can use it in service centre, party and many of other places where regularly servicing is required. A pumping motor is required for liquid supply which is poured inside the liquid. Just push buttons and a pumping motor will start to supply the liquid untill the limit is reached. In my project, I use a 5-pin socket for AC pump connection externally.
There are three buttons (START/STOP, UP and DOWN) to work with this project as seen on the picture. When powering the circuit, one time measurement is required to save an amount of 100% measurement. Finally the output depends upon how much percentage is required which is set by user(it can be 1% to 999%).
These are the screen shots of LCD display.
We can understand its function in the following two easy steps :
Step 1: Let 1 litre of water is need to save as 100% measurement. For this purpose, press ‘UP & DOWN’ button simultaneously to start the measurement then the pump will start to supply liquid untill the ‘STOP’ button is pressed. When 1 litre of water is completed, press ‘STOP’ button and hence this amount is saved.
Step 2 : Now its time to take the output. Suppose we need 2 litres of water then set the output to 200%(because 2 litres = 200% of 1 litre) by pressing UP/DOWN button. Finally press the ‘START’ button and you’ill see that the pump starts to supply the liquid. When amount of supply reaches to 2 litres, the pump will automatically stops. If you need ½litre of water then set the output to 50%(because ½litres = 50% of 1 litre) and hence so on upto 999%.
The working principle is based on a proportionaly function “amount is proportional to time” and requires some calculations. When we start to save a measurement the counter counts the time lapsed to supply the liquid. When the output is set to a particular percentage the count is devided with respect to time.
Download the complete source code.
Note : Use good quality of pumping motor to prevent harmonics which causes error in LCD reading. Also use required length of wire. Extra wiring produces interference.