Working MOSFET and arduino wont work together

Other Hardware Motors, Mechanics, Power and CNC
1

So I am in the process of developing an Arduino "Mosfet" for my airsoft aeg to allow me to program every detail of the RIF. The issue I am encountering is that when installed on my PCB my N-channel MOSFET (PSMN1R0-30YLC) and arduino pro Mini dont want to work together.

My circuit is as follows, Pin 2 of the PRO mini goes to the gate of the MOSFET with a pull down resistor (10k) to ground.
Source of the MOSFET goes to Ground
Drain to the motors negative terminal.

When the Pro mini is installed onto a breadboard it seems to be working perfectly being able to power LED's from Pin 2. (I have also tried multiple pro mini's in the setup to ensure it wasn't a fault with one.)

Additionally the Mosfet (PSMN1R0-30YLC) when given a straight 5V from the voltage regulator works perfectly with no signs of damage. However when I attempt to switch the gate with the arduino it only gives the pin about 0.1V for a split second while it flashes the pro mini's on board LED. The LED then flashes about once every 5 Seconds and when it flashes the output turns on to 0.1V.

NOTE: I have tried this with and without a GATE resistor and I have also varied the pull down values from 4.6K to 56K.

Attached is a picture of this part of the circuit.

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2

Do you have a wire from the motor power supply GND ( - ) to Arduino GND? Electricity doesn't flow through dry air, you know :slight_smile:
And you should have a 150 to 220 Ohm resistor between gate and output pin.

3

Yes everything is connected to a common Ground :slight_smile:
And when you say between the gate and output do you mean the pin on the arduino or which output?

4

You should have a series resistor (180 Ohms minimum) between the output pin driving the MOSFET gate, and the gate. The 10K resistor should be connected between the output pin and ground, not the gate, as shown below. You need a 5V Arduino for that transistor.

If you forgot the inductive kick diode and powered it up with a motor connected, the transistor may have been destroyed.

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dc motor driver.jpg
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5

I have the circuit wired as above with a flyback diode and both resistors of both 10k and 180 (also tried 350) and it still wont work. The arduino is able to output 5v when not connected to the mosfet, when the output goes high the voltage on the pin spikes for a split second which allows the mosfet to attempt at turning the motor but after that it stops.

Also what is the function of the cap in parallel with the motor?

Thanks

6

The 180ohm value is not critical.
The 100n ceramic cap suppesses radio interference from the sparking brushes of the motor. Not critical either.

Show us a clear picture of the setup/connections.
Leo..