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Topic: More than 3 GND pins on Arduino Uno (Read 3845 times) previous topic - next topic

mechanist123

I am trying to create a remotely controlled device that can control LEDs, two small step motors, and receive data wireless. I need at least four GND pins, but the Arduino Uno I'm using only has 3 pins. I'm using a MOSFET transistor to control the LEDs, so this takes up one GND pin. Each step motor needs one GND pin (I'm using the 28BYJ48 step motor and a driver board), which brings the total up to 3 GND pins. However, I need one more for the receiver. Is there a way to have more than 3 GND pins on an Arduino Uno? I've tried looking around on the forums and google but haven't had much luck.

Thanks for the help!

PaulRB

Hi, why don't you just daisy-chain the grounds?

Will all the devices draw their current from the uno? The max you can draw is around 500mA I believe. You should add up the current drawn by each of your devices.

Paul

runaway_pancake

Make up a "mini shield", a Grounduino, that provides a Ground bus (?).
"Who is like unto the beast? who is able to make war with him?"
When all else fails, check your wiring!

1ChicagoDave

#3
Aug 04, 2013, 07:35 pm Last Edit: Aug 04, 2013, 07:41 pm by 1ChicagoDave Reason: 1
Or just take a few extra header pieces and solder yourself up a splitter-cable. Four female inputs, two male outputs (all connected together), plug right into the two GNDs next to each other on Arduino board.

(Example of "cables" I made by soldering to headers --)

larryd


Make up a "mini shield", a Grounduino, that provides a Ground bus (?).


Grounduino, I like that!
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mechanist123

Thanks for all the helpful replies! Each step motor draws 92 mA while the LEDs have a separate power source and are controlled through a MOSFET transistor. Not sure how much current the receiver will draw, but I don't expect it to be a whole lot.

Paul, I'm not sure what you mean by daisy chaining the grounds. Do you mean connect two ground wires together and then plug one of them into a GND pin? Or is daisy chaining similar to wiring devices in series with one device's output going into the next device's input? Won't wiring in series raise the voltage above the 5V that the pins put out?

If the +5V pin can put out 500 mA, then would it be okay to wire the step motors in parallel and connect them to the 5V and a GND pin? That would cut down on the number of GND pins needed.

Again, thanks for all the help!

thepenguin

daisy-chaining means connecting two grounds together, and then having one wire that goes into the ground, not two.  You don't connect them in series.

mechanist123

Oh, okay. That makes more sense. Thanks!

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