is it possible to power arduino and a 12v pump by a single 12v power source

guidance needed with this plant watering set-up

i've hooked up a 12v power source to a 9v voltage regulator which powers the arduino through Vin & gnd.

arduino sends out a signal through pin 8 (or any other digital pin) to switch on the 5v Relay.

the postive lead on the relay output comes straight from the 12v power source and should provide the pump with power, as the negative lead from the pump goes straight back to the power source.

the problem is: as soon as the arduino turns on the relay the circuit seems to short, and messes with the arduino and the relay only truns on for 1ms or so.

my question is, as stated in the subject: is it possible to power arduino and a 12v pump by a single 12v power source? And if so, how should i rebuild my circuit to make it work?

circuit added as attachement.
thx

2020-05-15 17_40_38-plant water systemNetjes.fzz - Fritzing - [Breadboard Weergave].png

Is that really the power supply that you are using? If so, 12V/3W means the current output is 250mA max. What is the stall current rating of the motor?

my question is, as stated in the subject: is it possible to power arduino and a 12v pump by a single 12v power source?

Yes it is, but the power supply must be able to supply the required current. That would be the stall current of the motor, the coil current of the relay and the current required by the Arduino and its peripherals. I would use a Dc Dc converter to drop the 12V from the battery to 5V and connect that to the 5V of the Arduino, bypassing the weak 5V onboard regulator.

currently i am testing with a 12v 2.2a power supply, eventually i will use a (similar) car battery for the final set-up. Don't know much about the motor except for its pump used for windshield cleaner from a car.

That is one reason that we do not like Fritzing. People put parts in that look good but do not represent what is actually there. So we waste time while we wait to find out what is actually being used.

What do you see if you monitor the 12V supply with a DMM while the project works? Is the 12V steady or does it drop out when the motor turns on?

79b8d125a7d780c723a4c436b79907d9b04d65a0.png
You need a regulator to supply 5 V to the Arduino via the "5V" pin as well as the relay module - which latter requires about 90 mA to operate.

You could use a 7805 with its input and output capacitors - which you have not shown on that diagram so your 7809 may be oscillating - but you would need a proper heatsink. Much better to get a switchmode "buck" regulator module.

groundFungus:
That is one reason that we do not like Fritzing. People put parts in that look good but do not represent what is actually there. So we waste time while we wait to find out what is actually being used.

yeah sorry about that, just used it for the first time yesterday. couldnt find all of the parts right away. should have either explained it more propperly or use the right parts.

What do you see if you monitor the 12V supply with a DMM while the project works? Is the 12V steady or does it drop out when the motor turns on?

going to check this in a couple of days, but i have a hunch that indeed the voltage drops and it is not able to power the relay propperly through the arduino.

Paul__B:
You need a regulator to supply 5 V to the Arduino via the "5V" pin as well as the relay module - which latter requires about 90 mA to operate.

You could use a 7805 with its input and output capacitors - which you have not shown on that diagram so your 7809 may be oscillating - but you would need a proper heatsink. Much better to get a switchmode "buck" regulator module.

also going to check this solution, have the feeling this might solve it (as it bypasses the arduino)

thanks to the both of you, will update in a couple of days