Hi,
I am creating a "small clever greenhouse" controlled by arduino as a project to school. Everything is fine, but water pum doesnt work. I control it with mosfet tranzistor. It has the same 12 V power suply as arduino Mega (also tryed to wire it as two independet circuits with two independent suplyes). I dont know why, but when the water pump switches on, after random time period starts arduino behave strange and switches of waterpump and dyspley or doesnt react (no restart,still keep going). When I tryed to devide waterpump circuit (just waterpump in 12V suply) and arduino circuit, the problem was still there. I gave water pump circuit in bigger distance from arduino and suddenly it worked. But when I again connected both circuits on one power suply and transistor again (electromagnetical water pump was far from arduino), it stoped working again. I think there must be some electromagnetic induction in wires or something, I really dont know. I am out of any ideas. Please help
Sounds like a brown out (possibly missing a capacitor), please show us a schematic of how its wired.
Always show us a good schematic of your proposed circuit.
Show us good images of your ‘actual’ wiring.
Give links to components.
Are any of the connections for the water pump going through a plug board? If so remove them and solder together or use an appropriate wire connector.
For the waterpump not, just for connection of mosfet and signal pin from arduino
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Please draw every component in this circuit, showing the component and its connections.
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Review this
https://learn.sparkfun.com/tutorials/how-to-read-a-schematic/all
Looking at the pictures I understand why you are having problems. Leads on the processor should be no longer then 10"/25cm. Reason they make great antennas that are sensitive to EMI. They must be kept away from power and when they cross power it should be at 90 degrees. Can you place the Arduino in a grounded metal box?
Your wiring diagram is not a schematic, it is far from one and does not have the needed information.
Add a 470uF 16v capacitor to the Arduino power pins.
Ok, thank you, I will try to cover arduino in metal box. What do you mean with the leads on processor? Wires on Arduino? And is the lenght of that leads somehow connented with EMI?
Would that help with EMI problem?
The IRF520 MOSFET is a very poor choice for Arduino, as it can't be switched fully on with 5V logic. It and the pump motor may be overheating.
Either use a logic level MOSFET, or relay module for the pump motor.
Also, the diode across the motor terminals is drawn backward. Check whether it is the right way around in the actual circuit, which should look like this:
I tryed relay already, but nothing changed
Then the motor power supply may be overheating and shutting down. If that is the case, you will need one that can easily handle the pump current.
Small DC motors can draw 5 to 10 Amperes when starting up.
Well, there is not problem while starting
My power suply has 12V and 3A and the water pump shouldnt need more than 1A (while starting more, but starting is working)
Please post the actual pump specifications.
I see breadboards in the photos of your setup. They are designed for temporary experiments with low power logic circuits, and cannot handle motor currents. The tracks tend to burn out.