automatic water pump

[vead]

Hello
I want to make automated system that will control flow of water on basis of time

water pump motor
Voltage: 12V DC
Flow capacity:1 Litres per minute

microcontroller : 8051

example
If I need 1 Litres water then turn on water pump for 1 minute

If I need 2 Litres water then turn on water pump for 2 minutes

If I need 3 Litres water then turn on water pump for 3 minute

how to control flow of water using controller on basis of time?

 

[chopnhack]

My guess would be that you would need to know when the valve opens to start the cycle and then use the internal clock or feed an oscillator into the μcu to keep track of time. Then program the μcu to fire the solenoid at appropriate times.

 

[vead]

My guess would be that you would need to know when the valve .

which type of valve are you talking ?
I am thinking , mcu pin---> motor driver IC ---> pump motor
set time by programming mcu

 

[chopnhack]

Ah, yes my mistake. When I first thought of the problem I was thinking constant flow of water under a constant pressure.

You are correct, pin to a motor - you will have to figure the delay for priming the motor, head, delays to steady ouput if there are any, etc. to come up with the an appropriate variable to add plus time to achieve a per liter output.

Will there be concern for drainage/leak down of pump when the circuit is not used for awhile? Any feedback mechanisms like a flow meter downstream of the pump or a float switch if there will be a reservoir?

 

[vead]

Ah, yes my mistake. When I first thought of the problem I was thinking constant flow of water under a constant pressure.

You are correct, pin to a motor - you will have to figure the delay for priming the motor, head, delays to steady ouput if there are any, etc. to come up with the an appropriate variable to add plus time to achieve a per liter output.

Will there be concern for drainage/leak down of pump when the circuit is not used for awhile? Any feedback mechanisms like a flow meter downstream of the pump or a float switch if there will be a reservoir?

mcu pin---> motor driver IC ---> pump motor

I am seeing only two connection of pump motor (supply )

how to connect pump motor with MCU?

 

[Minder]

A logic level gate Mosfet will do it.
M.

 

[chopnhack]

mcu pin---> motor driver IC ---> pump motor

I am seeing only two connection of pump motor (supply )

how to connect pump motor with MCU?

I am not sure of what you are asking. Are you asking how to connect the physical (wires) of the pump motor to your circuit?
Agreed, as I typed was going to say mcu leg to transistor to pump. The two leads of the pump are split between the source and return. Is this an AC or DC motor?

 

[Gryd3]

What's more important.
-The run time.
-The water volume.

You need to be sure that your pump is accurate. Or you can call it good enough and just run it for a minute.
Additionally, you could use something like a paristaltic pump, and count the rotations it makes. This would be less dependant on timing and more accurate for volumes.
These pumps are very easy to make by yourself as well and can be food safe depending on the purpose of the water.