Sammer has noticed about his latest project called liquid supply system. You can see a good example of such device when filling petroleum. It pours exact amount of it. The solution is pretty simple – it is based on time value rather than debit counter. So before usage, it needs a reference value which is taken by measuring 100% value. This is done by running pump as long as desired amount is pumped. Say its one litter than its 100%. Once the value is stored you can pour like 5 litters by setting value of 500% on LCD and starting the pump motor. Once liquid is poured, it stops automatically.
This by far not the most accurate way of doing this, but if you get right reference value and pump flow is constant, then it serves pretty good. The most attractive thing here that it is setup is simple – microcontroller, and motor relay. No real measuring is done.