controlling multiple micro vibration motors

Projects General Guidance
1

Hello,

I'm working on a project where I would like to control up to 5 3V coin micro vibration motors individually. The idea is to have them vibrating in a sequence, turning on and off one after the other.

I have multiplied the circuit and tested with 3 motors so far. The problem is that it is only the circuit connected to pin 3 on the Arduino that turns on.

Does anyone have any ideas to why the other circuits are not turning on and/or if there is a problem with the circuit itself and how it is powered?

I would be very grateful for any help or leads on this.

Here is the code I'm using:

  const int motorpin1 = 3;
  const int motorpin2 = 4;
  const int motorpin3 = 5;


void setup() {

    pinMode(motorpin1, OUTPUT);
    pinMode(motorpin2, OUTPUT);
    pinMode(motorpin3, OUTPUT);
    Serial.begin(9600);
}

void loop(){

    digitalWrite(motorpin1, HIGH);
    delay(100);
    digitalWrite(motorpin1, LOW);
    digitalWrite(motorpin2,HIGH);
    delay(100);
    digitalWrite(motorpin2,LOW);
    digitalWrite(motorpin3,HIGH);
    delay(100);
    digitalWrite(motorpin3,LOW);
    delay (1000);


}

schematic_multiple_buzzers.jpg
schematic_multiple_buzzers.jpg842×631 140 KB

2

schematic_multiple_buzzers.jpg
schematic_multiple_buzzers.jpg842×631 140 KB

3

schematic_multiple_buzzers.jpg

Amongst the problems with your arrangement there, are the fact that you are apparently using IRF520 FETs which are not logic-level in the first place, and you are driving them with a voltage divider so they probably do not all turn on due to a spread of individual parameters.

This circuit might work with transistors, but not those FETs.

For the present, try removing the 1k resistors.

4

Hi,
Check your protoboard for a break in the power bus down the side, it splits the power bus, so only have power on one half on each side.
protobreak.jpg
Tom,.. :slight_smile:

protobreak.jpg

5

Yes, I'd suggest the same, gaps in breadboard bus bars - a trap for the unwary (the gaps are
great for RC filtering sections of power rail which is what they are presumably for.)

One lesson to learn - use a multimeter to check for voltages, any new circuit test that power is getting
to every device that needs it. Your eye's can't see voltage!

6

Thanks for the replies.

I have connected the two halves on the breadboard and now all the motors are turning on!

I will also replace the FETs with transistors.

Thanks for the help!

7

How much current do those motors take? Chances are you can run them using a TPIC6B595 shift register, without the need for external transistors.

8

Paul__B:
This circuit might work with transistors, but not those FETs.

Which type of transistor would you recommend instead of the mosfet?

9

What is the current specification of those motors?

10

wvmarle:
How much current do those motors take? Chances are you can run them using a TPIC6B595 shift register, without the need for external transistors.

They run on 3V

11

Third (and last) time: what is the current specification of those motors?

12

Sorry for the misunderstanding.

I simply don't know and I don't have access to a multimeter at the moment.