for my first project using Arduino I want to control a waterpump
by sensors connected to the Arduino.
While I am reading the forums und webpage regarding similar topics, I realized I need an relais to start/stop the water pump.
As both Arduino and waterpump works with 9-12V I am currently wondering, if there is a way to use the same power supply for both of them.
My first idea was to just connect both the the breadboard, but however the water pumps current of 2A made me uncertain, if the breadboard will deal with that. I found some topics, where it is suggested not to use more than 500mA on the board.
Is there another way to connect both Arduino and waterpump to the same power supply?
For the future I'm thinking of adding a second water pump, so ideally the solution should handle even more current flow.
Is there another way to connect both Arduino and waterpump to the same power supply?
Connect a 5V buck converter to 12V source and connect the 5V to the Arduino 5V input. That bypasses the weak on board 5V regulator and helps to isolate the Arduino from the motor noise.
Connect the pump to the 12V supply through a logic level MOSFET (instead of a relay).
Is the stated max current the stall (starting) current? If not, you need to find out what the stall current is because that is what the power supply must supply each time that the motor starts and you will need to know the stall current to spec a MOSFET driver.
Do not try to pass 2A through a solderless breadboard. I would solder the circuit up on a proto board.
The important question is what voltage and current is needed to switch the relay. All the Arduino is doing is switching the relay. The relay is controlling the 2A going to the pump (and the connections to the pump must NOT go through a breadboard).
So exactly what relay are you using? If it's a 5V relay module then you should be able to run everything from one power supply.
@grounfFungus
If I understand you correctly, the "5V buck converter" is the thing you suggested me to use. Can you give me a link of that part?
And a second question: What's the advantage of using a MOSFET instead of a relais? As far as I know, both are doing exactly the same: switch on/off the 12V signal dependent on the input potential.
To be honest, for the beginning I would not start directly with der soldered board, but using a breadboard to gather experience and optimizing what I did.
@slipstick
Regarding the Relais I found some reports, where people have been used this one:
One advantage to using a MOSFET instead of a relay is that once turned on the MOSFET draws virtually no current. A relay must have current through the relay coil all the time that it is on. A relay cannot be driven directly by an Arduino output. A relay needs a transistor driver. So just drive the motor with the transistor and skip the relay. Relays wear out, MOSFETs, if chosen properly, will last much longer. Also, if you want speed control with PWM you cannot use a relay.
