Temporizer Machines - Coin and Bill. Question?

I have a small water filter business and I want to start installing machines in which I can fill up persay a gallon of water with the insert of a coin. I assume it has to do with a mechanism of timing since it does take time for water to fill up a certain volume. I want to know the Mechanism/procedure of... show more I have a small water filter business and I want to start installing machines in which I can fill up persay a gallon of water with the insert of a coin. I assume it has to do with a mechanism of timing since it does take time for water to fill up a certain volume. I want to know the Mechanism/procedure of this.

Any help would be appreciated.

Thank You
1 answer 1