vibrating motor

Hi there, I read a few topics about this but I'm not sure I understood exactly what to do.
I wanna drive this motor and the speed of the vibration should change, according to an input.
First of all:

  • can I drive this motor using arduino 5V? Should I use any diode to reduce this voltage (which kind of diode)?
  • is this scheme fine? I'm not sure I understood why of the 1N4001 and the 01uF

thank you!

L.

You probably can. The diode and the C are there reduce the noise and protect against back emf. The 33ohm resistor is there to drop the voltage. Note how to put the diode in the right way, otherwise you just create a dead short :wink:

Quick calculation
75mA @ 3V for the motor.
So 2 volts across the resistor. 2V / 33ohm = 60mA.

So yeay, that's fine. It runs slightly under it's max current and voltage but that's okay.

first off, you would be better to drive the motor from a separate power supply. data sheet shows 75ma, so that consumes a lot of your available power.

your question about driving a 3v motor with a 5v power supply is valid. check the spec of that 4007 diode. it has a 1.1v drop, so would drop voltage, maybe not as much as you like, but some. you might find that 2 will do the trick.

the motor, like any motor, acts like a motor when powered and like a generator when power is disconnected.
in addition, the coils are charged to create a magnetic field, when that field collapses, the filed turns into an electrical spike on the input wires. we call this back emf. ir rarely is more than about 20% of the input power, but it does exist and can most definitely destroy things.

you have both a cap to absorb some of that, and a diode that is designed to short the wires together in the event of a spike.

To control the speed you can use PWM from an Arduino pin driving a transistor that
controls the motor. For 75mA practically any small NPN transistor like the 2N2222
would be fine, just add 1k base resistor and place motor+diode between collector and
+5V. The cap is between ground and 5V (the transistor emitter is at ground).

MarkT:
To control the speed you can use PWM from an Arduino pin driving a transistor that
controls the motor. For 75mA practically any small NPN transistor like the 2N2222
would be fine, just add 1k base resistor and place motor+diode between collector and
+5V. The cap is between ground and 5V (the transistor emitter is at ground).

thanks, could you please draw a scheme?

thanks!

Just use the schematic you posted, that’s just it! :wink:

ah ok, good!! thanks! the blue 0.1uF is a capacitor right?

L.

Yessss :slight_smile:

cool!

thanks a lot! :slight_smile:

L.

Hi again, I’m going to purchase the components but I am not able to find the 2N2222. I read aroundthat I can substitute it with this one or this one. What do you think?

thank you!

L.

Yeay, just the cheap one. Or just a BC547 or something. Doesn't really matter, as long as it can handle the current en voltage. But with 75mA and 5V that's not to hard...

Hello again! So i received the components and everything is working..! Now, I have a sensor (as input) and I want the values read from this sensor to become the amount of vibration of the motor..right now the vibration is just setting the pin as HIGH/LOW every 1 second. How do I change these values with the values coming from the other sensor?
thanks!
L.

edit: I solved it with PWM then I'll change question.

actually with analogWrite(255), the motor is not vibrating a lot. What should I do to have even more vibration? change any resistance? but which one?

thank you!!
L.

Are you running it at 3V currently? You could try 5V (although you risk overheating the thing
if its only rated for 3)

Depends, do you have a multi meter? Measure the voltage over the motor (after you only did digitalWrite(pin, HIGH) ). Is it 3V? Because that's the maximum. If it's already 3V you're kind of out of luck. You can try to feed it more but you risk overheating/damaging the motor.

actually I'm feeding the circuit with the 5V as the tutorials said.

thanks!

L.

Yeay, but because of the resistor in series with the motor the actual motor gets around 3V. Because that's where it's spect at...

ok..so I think I won't get any stronger vibration then..thank you anyway :slight_smile:

leech:
Hi again, I'm going to purchase the components but I am not able to find the 2N2222. I read aroundthat I can substitute it with this one or this one. What do you think?

thank you!

L.

I thought I'd mention that the difference between a 2N2222 and a 2N2222A is
the process used to make the silicon. It is made to the same spec, it is just
rev A and the first was the first. I don't think anyone even sells non-A parts
any more.
As for the plastic case, this is a cheaper version because it has no metal case.
It is the same except for power dissipation. This may not be an issue for
you since you are running your part in saturation and not in the linear analog region.
Dwight