I have the brushless motors working with the Arduino Nano. Now I am trying to put a MOFSET on the brushed motor and control it via Nano. Is this diagram correct. I am just guessing here.
First of all get your terminology right. It's a MOS FET. The gate of your "MOFSET" is grounded and the source goes to an Arduino pin, so it won't work. You have to reverse those two, but when you do that, you have to fix a problem. The NO switch that controls(?) the MOSFET would leave the gate "floating" if it is open. You really need to get up to speed on MOSFET circuits, you can't guess your way through this one.
Its hard to understand this diagram. A schematic would be much clearer. But the connection of the MOSFET looks wrong. The Gate appears to be connected to ground and the Source to a Nano digital output pin, via what I assume to be a switch.
General MOSFET rules:
SOURCE goes to Arduino Ground and negative side of motor power supply
DRAIN goes to negative side of motor.
GATE goes through a resistor to the Arduino OUTPUT pin.
Positive side of the motor goes to the positive side of the motor power supply.
To prevent an accidental turn-on due to things like power to the Arduino failing or a bad upload leaving the OUTPUT pin as a floating INPUT, add a 10k Ohm resistor between the Arduino OUTPUT pin and Arduino Ground.
The gate of the MOSFET acts like a capacitor and charging the capacitor causes a current spike that may exceed the 40 mA absolute maximum for an Arduino pin. At 5V a 240 Ohm resistor will limit the current to near 20 mA which is plenty safe. Anything from about 160 to 1000 Ohms should do if you can't find one near 240.
Thanks to most of you for the help. I have modified the diagram according to JW's information.
Please let me know if the modifications are correct.
Those limit switches will never work like that, they should be connected to input pins and their states(ON or OFF) used in the program control logic.
GregHeffner:
Thanks to most of you for the help.
Most? Who has been anything less than helpful?
GregHeffner:
Please let me know if the modifications are correct.
Incorrect. You missed or ignored what I said about the NO switch leaving the gate floating. JW also mentioned that. OP's modified diagram:
I have already fixed this from JCA34F comment.
GregHeffner:
I have already fixed this from JCA34F comment.
Then please post an updated schematic. I'm referring to the thing labeled, "Momentary Contact NO for brushed motor". Basically we're talking about the 10k resistor. You put it on the wrong side of the switch, it must be on the MOSFET side, not the Arduino side. This means that the issue "To prevent an accidental turn-on due to things like power to the Arduino failing or a bad upload leaving the OUTPUT pin as a floating INPUT" that was posted in reply #3, is not fixed. It is still floating when the switch is open. The JCA34F comment had nothing to do with that.
PaulRB:
Most? Who has been anything less than helpful?
From the PM that I got, I gather that it was me.