How To: Multiple motors connection


First of all, pardon me as i’m a newbie… :blush:
My background is at programming and i’ve recently been commissioned to build an installation at an event where i believe arduino may help.

The project is to build a series of fans, around 30, (doesn’t need to be CPU fans, can be just motors holding a strap of plastic or card), where i blow into a microphone and it outputs the force to the fans making them start.

The code to make that work is not a problem. I can make that work with ease… What i’m struggling with is to find out how to connect multiple motors to an arduino, is that even possible? i’ve search around and it got me nowhere, maybe here you can point me to the right direction.

Sorry if this has been asked before… i have not found a simple answer for this many connections to a single device… ( money is not an issue here - in case more devices are needed - suggest solutions as you will )


What i'm struggling with is to find out how to connect multiple motors to an arduino, is that even possible?

Depends on how you want to do it, and how much control you need over the motors.

If you just want to turn the motors on, a simple relay that controls power to the motors will suffice. A SSR or transistor controlled relay will be controllable directly from a digital pin.

If you need to vary the speed of the fans, or turn only some of them on, things get more difficult.

Your requirements are?

Thanks for the reply Paul,

I need to control them independently,(sort of: they will be stacked in columns) but i do not need to control the speed.
Because they will be stacked in columns i do need to control which columns should i activate depending on the force of the blow. (hence the sketch : the asterisks show an example of simultaneous columns that need to be activated at the same time ranging from 1 to 6 - 1 column min, 6 activated columns max).

Is it easier to treat them independently? or can i group them in some sort of shields or control drivers? (or am i going totally the wrong way?)


Hope i gave you all the info you need.


6 columns of fans is easy to control with 6 digital pins. These Relay SPST-NO Sealed - 30A - COM-00101 - SparkFun Electronics
along with a few simple parts make it easy to control the fans.

Thanks for giving me these tips, :slight_smile:

I still don’t know how to group the motors, would they be connected directly or do i need something between them? do i need a diode across the relay so the relay doesn’t fail prematurely ?

I’ll keep looking for tutorials, from the basic basics…

Thanks for the help.

EDIT: i made a sketch to know if i got things right…

You can connect motors in parallel.
Look for shields, as I understand, you are not qualified to build electronics.

Yup, i'm not qualified at all.... this first shield you showed me looks exactly what i need to connect the rows.

I'll keep googling on how to connect in parallel and such... (my bet is that there are alot of "multiple connections in parallel" tutorials out there, so i'll try to find one that suits me).

It's still somewhat consfusing, i understand the concept but when it comes to actually get the wires and pin them down, thats where i'm lost...

Thanks for all the help.

Look at wiki:

Find a book:
Make: Electronics
Learning by Discovery
Charles Platt
and some day, you will design such shields on your own :slight_smile:

I think i know what to do now… i’m ordering the stuff i need:

1x arduino uno
1x relay shield (with 6 relays)
1x 12v battery
30 x 3vdc motors
30 x 4" propellers

and i think thats all i need.

could you comment on the “very professional” scheme i drew to know if i got it right?

Thanks :slight_smile:

1x 12v battery
30 x 3vdc motors

Why do you think you need 12V battery for 3V motors?
Should be the same.

the relay shield only operates at 12v or did i get that wrong?

Yes, you are right. Will be arduino powered from the same 12V battery?
It would make sense, to order 12V motors, so you will need only one source of power for all staff.

I was thinking about powering the arduino through the usb cable, as i need to send data to it at runtime....

Any tricks i need to know to not kill my board when doing this?

Arent 12vdc motors overkill for a simulated fan? they cost so much more...
pc fans run on 12vdc right? maybe its not overkill. maybe i should just buy pc fans instead of motors and propellers....

I'm thinking, if arduino would be connected, instead of battery you should use power supply plugged in AC outlet. Relay usually drain a lot of currents, and battery probably, would discharged too fast. If 12V motor is expensive, than you can go with 3V motors and buy separate 3 V power supply. So you would need two of them, 12V for relay board , and 3V for motors.
Other option to eliminate 12V from a map, is find a relay board that could be powered from arduino +5V, and it should consume less than 500 mA.

@crociquia, (or anyone else with input/advice!)

Let me just say how excited I was to come upon this thread! My current project has a lot in common with you and I read and re-read this thread, looking up all sources and materials. About me; I am a masters architecture student currently working on my thesis project in which I am collaborating with engineers. We are designinsg and building an environmentally responsive ‘curtain’ of sorts. This curtain is made up of many inflatable components. Each component has the potential to inflate or deflate thanks to a light sensor (each component has a light sensor and a fan attached to it )that triggers the arduino to tell the fan to blow in the positive when hit with light and reverse direction (suck air out) when sensing dark.

How did you project turn out? I see that the ‘sensor’ in your project is based on volume/sound input.
The sensor in my project is related to light. Right now I am struggling with figuring out exactly the right light sensor which will be attached to an inflatable component. (If anyone reading this has any light sensor suggestions that would be great! I have a list going but the important aspect is that these wont be directly attached to the arduino board. They have to exist inside these inflatable components. (see sketch attached) This light sensor will most likely have only 2 inputs and not work on a scale. IE it will trigger the arduino to tell the fan to turn in the positive direction when dark (filling the component with air) and turn the motor in reverse when the sensor senses light. (sucking out the air from the component)

I am dealing with the following issues. Many are the same as your past project.

  1. hooking up multiple pc fans to 1 arduino board-
    Did you resolve the power supply issue? Did you use an external 12 v DC power supply or did you follow @magicians suggestion of finding a relay board that can handle the large amount of voltage and channel it to the 5v arduino?

  2. relay board- I realize that you needed a relay board to assign 5 fans to one relay as you had 6 columns of fans, and you needed the columns to act together as one. Is that correct? Since my fans are all acting independent of one another, ie responding to their individual light sensors, Do I need a relay fan ? I know I need something that will handle the overload of voltage going to the 5v arduino board.

  3. physically handling the wiring from that many fans-
    I am assuming you had an interesting layout and we are talking about long chords all ending at one point/the arduino board. How did the wiring turn out?

  4. Reversing motor direction of fans-
    I have found a helfpul link here about reversing motors but if anyone has any specific tips about my project wow that would be much appreciated!

5)Finally, @crociqua if you are open to sharing your code that would be incredibly appreciated. Pictures or a link to your project would be great too! love those arduino + fan projects! Ha

ps see the attached PDF for hopefully a more helpful explanation of project goals/issues!


Leslie Mignin

fanlightsensorinflation.pdf (543 KB)