vibration motor cannot stop!

Hi, fast question, im using a vibration motor activated by a relay ( solid state). When i plug the motor alone, it works perfectly , stop and go , stop and go....but when i introduce the counter weight to add vibration, the motor never stops, it doesnt obey the relay anymore. its typical toy motor , with a supply of 9v.

it has a parallel diode to cancel the energy generation form the motor, should i add anything more? thanks!

Is there a poor connection somewhere that is aggravated by the vibration?


everything is ok.
Its like the relay is activated forever one time i say arduino to put HIGH the control pin. and then the LOW doest work, the only way to stop it is to unplug the motor and plug it again. and this only happens if the motor is running with a weight in it. without everything goes ok.

everithing its ok.

If it was you wouldn't be asking questions here :slight_smile:

Is the relay isolated from the vibrations?

Vibration motors are usually tiny and draw very little current but is it possible that it draws more current when the weight is attached and that screws things up (the straw that breaks the camel's back). It would be a good idea if you post a copy of how everything is wired up. A photo of a clear pencil sketch would be fine.


Your motor with weight will have a fair amount of inertia (tendency to continue to do what it was doing before you turned the power off) Motors also act as generators when they are turned with no power supply.

What is possibly happening in your case is that when you de-energise the relay, it opens the motor contacts and disconnects the power to the motor, but the motor then acts as a generator and produces sufficient voltage to somehow hold in the relay which then re-applies power to the motor.

Obviously this isn't meant to happen if your circuit is wired up correctly so either you have a mis-wired circuit or the actual circuit design is flawed. can you therefore please supply either the circuit or an EXACT drawing of what you have built.


the system have dual power supply, they share common ground. i just have a diode between the motor terminals.
they motor is moved with -9v to GND connection.
thanks a lot!

  • i wrote the last message with my mobile phone. i will care more typo and mistakes from now sorry ;/

Try putting another diode between the relay and the motor so there can't be a back-feed.

Is it the sort of tiny motor that is in a mobile phone?


its a 9v motor, like this

i just tried to put a diode between the relay and the motor and...the same :confused: , the motor keep going.

That picture is not very informative - have you a link to the motor specifications?

It looks like it is much bigger than the motors that go in mobile phones. Is the SSR big enough for the job?

You haven't said whether the physical vibration of the motor is isolated from the rest of the hardware.


here the same motor

and yes it's isolated by cables, like 1 meter at least, the hardware doesnt suffer any vibration.

Continuity tester on the relay will show if the contacts have welded together or shorted somehow.

Continuity tester on the relay will show if the contacts have welded together or shorted somehow.

Alas, the OP says it's a SSR and I don't know anything about them.

If it was my project I would try a mechanical relay and see what happens.