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Topic: How to wire Arduino + MOSFET to control AUX LED lights + CANBUS (Read 135 times) previous topic - next topic


Hello my friends,
I would need some advice on how to wire this circuit in attachment.

This is for connection of an Arduino + CanBus shield to control a Mosfet switch and turn on and off my car LED Aux lights.

I will use 12v and GND from a Canbus cable (4 wires) to power the Arduino via a DC switching power supply (12v to 5v dc), and the other 2 Can wires to Arduino Canbus shield.

From there, i have a Mosfet Power kit from Sparkfun to switch on/off the LED Aux lights.

Each LED Aux light is 12v 1,6 Amps (20W).

Can please help me with the connections between components ?  (+) (-) (GND) ... still confused...

Is the schematic correct ??

Many thanks!


What experience have you with Canbus and what do you want to do with the information it can supply.

It seems like a complex way to turn on a strip of LEDs..

I think me need complete explanation of what you are trying to achieve,

Thanks.. . Tom.... :)
Everything runs on smoke, let the smoke out, it stops running....


Hi Tom,

From the Canbus messages i will retrieve information regarding status of headlight low beam and DRL lights (which are both LED). Also get info from a photocell and according to the exterior lighting will trigger the Aux LED lights.

Regarding Canbus, i already have all the info and the Arduino is already programmed to react to those messages, sending an High/Low signal through a pin, to control the Mosfet.

I just need to know if the wiring route is correct acording to polarity and any other major issue that you may encounter...

I am using a Mosfet Power control kit because i already have one (should be also possible with a relay, but that´s the parts i have).

Luis V


Probably my biggest concern is the SparkFun Mosfet Power control kit.. I´ve included the schematics in attach...

Still confused in wiring the battery to this Mosfet and to the Aux LED lights..

Can anyone help?



Your ground looks wrong. You have a high current ground from the battery and another via the canbus cable. While it is obvious to us what you intend, electrons don't work that way. You may find large ground currents in the wrong cable.

If you hook it up casually while testing or the high current ground gets disconnected accidentally then you will definitely get a lot of current in the small cable, which may set it on fire.

Look at consolidating to one ground point on the chassis or make sure just the MOSFET is connected to the high current ground.
GoForSmoke: "What GShield? You never mentioned a shield."



Do you mean by eliminate the "GND" from Arduino to the Mosfet Switch?

Like this:

Arduino "Control" wire to N-Mosfet Gate
LED Aux to N-Mosfet Drain
Negative Bat terminal to a fuse and then to N-Mosfet Source?



Like, "Draw another diagram. Don't try to explain it in words."

Read up on "star grounding" too.
GoForSmoke: "What GShield? You never mentioned a shield."


I´ve draw another sketch.
Should be like this?

Thank you very much!!

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