Greetings all.. 
I have some problems in my graduation project.. I hope someone help me in that
I need to control 4 valves(2W-160-15) (DC12v) with water pump(bilge Pump)(12v 1.8A) via arduino MEGA-2560
my questions
1- I need relay module(4 channel) for that or only transistors with diodes?
2- I need external power supply or not ?
Thanks in advanced
*srry my english is bad **
logic level power mosfets - eg 30n06l's would be ok - but don't forget flywheel diodes.
YES - you definitely need a seperate power source - it sounds like your pumps could take up to 7.2A at 12v if they're all on , and will need a starting current much higher than this.
Allan
Thank you for reply,
I will use 1N4001 Diode is that good for me ?
and I will use 1 pump only it take 1.8A and the other 4 valves take nearly 0.6A
1 valve take 0.16A.. P = VI .. so 2/12 = 0.16A*4 = 0.6A
I'll need an extra battery for that, right? and hook it to my breadboard ?!
1N4001's would be fine.
And you'll need a 12 v battery capable of delivring >2A for whatever time you intend to run the system.
A car battery?
Allan
A solderless breadboard will fry with that kind of currents. A perfboard would work with proper wiring.
In your code, DO NOT switch them on at the exact same time, add a short delay if they all have to open. This as the startup current of a motor, and to lesser extent a solenoid, is much higher than the constant drawn current. This will put less stress on your power supply (though a car battery can handle peak currents quite well).
well... any suggestions about relay module( 4 or 8 channel)?
My full build will be(4 valves - 1 pump - waterflow sensor - current sensor for each component )
I'd use MOSFETs to switch that. Cheaper, smaller, no moving parts and no noise. Relays are better for switching really big currents, AC power or high voltages, such as mains.
Thank you a lot
I'll try Mosfet
Any MOSFET could fit ? 4 MOSFET right ?
One MOSFET is one switch.
And no, not just any will fit. You need a logic level one (to switch fully open at 5V, assuming your Arduino is a 5V one) such as the IRL540. Your MOSFET also has to be able to switch enough current (the IRL540 can do >20A) for your application.
Thank you I w'll try it..
another question plz:
I have ACS712 current sensor... I hooked up 3 pins into arduino(VSS-OUT-GND)
I connected WaterFlow sensor too.. How to measure the waterflow sensor current by current sensor
I don't have any DC power external.. I have only battery 9V
I just want to display and measure the current of waterflow sensor by the current sensor
there is a circuit or a way to show me that ?