Share ground pin with six PWM wires on one UNO?

Hi all,

I have six channels of LED stipes. Can I share the ground pin with all six channels? UNO has six PWM pins but it has one ground pin. Can I wire all six ground wires (+0V) together and then connect it to the ground pin on UNO?

Thanks, Michael

Of course. You should do that. Keep in mind the current your LEDs will draw. You don't want to damage your board.

changks:
I have six channels of LED stipes. Can I share the ground pin with all six channels?
UNO has six PWM pins but it has one ground pin.
Can I wire all six ground wires (+0V) together and then connect it to the ground pin on UNO?

You don’t have a choice, you MUST do that or you risk destroying the arduino + strips + everything else in the area.

I assume you have an external power supply for so many LEDs so you should connect Arduino ground to the ground on the power supply along with the ground from the LED strips.

Because it’s so critical, I wouldn’t just poke a wire into the Arduino edge connector, I’ve killed Arduinos by a ground wire falling out. These days I solder a wire to top of the Arduino USB socket then connect it to a screw terminal on the power supply.

I’m not kidding, here’s a picture of one of my Arduinos that’s been in a device which was used to drive LED strips. You can see the solder blob on the USB connector where the wire was.

CAM00061.jpg

Note that not only does the Arduino microcontroller have an absolute maximum rating for each pin, but there are total ratings for all the pins (and also per port IIRC), so in practice don't try to take more than 20mA per pin without checking out what the limits actually are for your chip. LED strips take more than 20mA, so you will be needing some sort of switching transistor or MOSFET for the strips.

The LED PCB will be powered by an external power adaptor directly. The total voltage has been well distributed to six channels. I want to do is that using PWM to control (dim and on/off) each channel. So, now I have six pairs of GND(V0) and PWM (5V) pins. I do want to damage the PCB or UNO because of the six wired GND on one UNO (one GND pin only).

Thanks all.

I do want to damage the PCB or UNO

Easier ways of damaging a board is hitting it with a hammer.

You don't distributive voltage you distribute current. You have not said what current you are driving with each PWM pin, so no one can advise you but in general it matters not there is only one or two ground pins as long as the total current is kept within limits.

Dear all,

I got my 48V 2A power supply last week. Now, It lights up six LED channels.

The wired things are:

(1) digitalwrite(pinx,HIGH) means the power off and digitalwrite(pinx,LOW) means the power on

(2) digitalwrite(pinx,255) means the power off and digitalwrite(pinx,0) means the power on

(3) digitalwrite(pinx,n) doesn't work, while n indicates 2~254.

Do you have any ideas why it happened?

Thanks, Michael

2) digitalwrite(pinx,255) means the power off and digitalwrite(pinx,0) means the power on

(3) digitalwrite(pinx,n) doesn't work, while n indicates 2~254.

You need analogWrite there.

My bad~ I just notice that! Thanks. : )

However, I’m still stucked on digitalwrite(pin, HIGH) shuts the light off.

Michael

changks: However, I'm still stucked on digitalwrite(pin, HIGH) shuts the light off.

Michael

Depends on the circuit, which you haven't shown us.

changks: However, I'm still stucked on digitalwrite(pin, HIGH) shuts the light off.

Yes it will if your circuit works by sinking current inplace of sourcing it. Please supply a schematic.