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Thread: Vibration Motor queston

  1. #1

    Default Vibration Motor queston

    I Have to calculate a resister for Vibration motor, is it calculated differently than LED's? Thanks!

  2. #2

    Default

    Like LEDs, rumble motors have an operational voltage and current range where the rumble intensity varies depending on the amount of current you give it. The calculation is the same (BatteryV - motorV) / I

    Using the example values of 2.5v - 3.5v @ 60mA max for the rumble motor and a battery voltage of 3.7v and limiting the current to ~80% of max to be "safe".

    (3.7 - 2.5) / 0.05 = 24ohm
    (3.7 - 3.5) / 0.05 = 4ohm

    This gives a resistor range of 24ohm to 4ohm where the 24ohm will be provide a fairly weak (if anything at all) rumble and 4ohm should be fairly intense.

    Ideally you would use a regulated power supply and multimeter to determine the actual voltage the motor needs for the given current. Alternatively you can experiment with different resistors within the rumble motors operational range. Avoid getting to close to the maximum range to be safe.

    -Denzil
    Last edited by Denz; 09-12-2014 at 05:58 AM.

  3. #3

    Default

    Quote Originally Posted by Denz View Post
    Like LEDs, rumble motors have an operational voltage and current range where the rumble intensity varies depending on the amount of current you give it. The calculation is the same (BatteryV - motorV) / I

    Using the example values of 2.5v - 3.5v @ 60mA max for the rumble motor and a battery voltage of 3.7v and limiting the current to ~80% of max to be "safe".

    (3.7 - 2.5) / 50 = 24ohm
    (3.7 - 3.5) / 50 = 4ohm

    This gives a resistor range of 24ohm to 4ohm where the 24ohm will be provide a fairly weak (if anything at all) rumble and 4ohm should be fairly intense.

    Ideally you would use a regulated power supply and multimeter to determine the actual voltage the motor needs for the given current. Alternatively you can experiment with different resistors within the rumble motors operational range. Avoid getting to close to the maximum range to be safe.

    -Denzil
    Battery is 4.7
    Motor is 3.0 volts
    4.7 - 3.0 = 1.7 / 50 = 34 ohm
    it is 95mA max
    the online calculator says 47ohm, 1W

  4. #4

    Default

    What battery are you running that is 4.7v? Li-ions are 3.7v each.
    We all have to start somewhere. The journey is all the more impressive by our humble beginnings.

    http://led.linear1.org/1led.wiz for the lazy man's resistor calculator!
    http://forums.thecustomsabershop.com...e-to-Ohm-s-Law for getting resistor values the right way!

  5. #5

    Default

    Quote Originally Posted by Silver Serpent View Post
    What battery are you running that is 4.7v? Li-ions are 3.7v each.

    Sorry typed it in wrong here, but did the math right on the calculator, 7.4V Li ion 2600 18650 PCB

    Battery is 7.4
    Motor is 3.0 volts
    7.4 - 3.0 = 4.7 / 50 = .094 ohm
    it is 95mA max
    the online calculator says 47ohm, 1W
    Last edited by setelf3of5; 09-11-2014 at 09:38 PM.

  6. #6

    Default

    Keep in mind that you may not want the motor to run at full speed. I've found that it can cause too much vibration and sound. A potentiometer or multiple resistors may come in handy to find the sweet spot you are looking for.

    Also, try to get a motor that's fully enclosed... The last thing you want is a spinning weight catching a wire and ripping things to shreds!

  7. #7

    Default

    Quote Originally Posted by setelf3of5 View Post
    Battery is 4.7
    Motor is 3.0 volts
    4.7 - 3.0 = 1.7 / 50 = 34 ohm
    it is 95mA max
    the online calculator says 47ohm, 1W
    Correction for my my values the "50" would be in milliamps so you need to divide by 0.05

  8. #8

    Default

    Quote Originally Posted by Denz View Post
    Correction for my my values the "50" would be in milliamps so you need to divide by 0.05
    Quote Originally Posted by TrypWyr View Post
    Keep in mind that you may not want the motor to run at full speed. I've found that it can cause too much vibration and sound. A potentiometer or multiple resistors may come in handy to find the sweet spot you are looking for.

    Also, try to get a motor that's fully enclosed... The last thing you want is a spinning weight catching a wire and ripping things to shreds!
    Thank you Trypwyr, and Denz for your help.

    Battery is 7.4
    Motor is 3.0 volts
    7.4 - 3.0 = 4.7 / 0.05 = 94 ohm
    it is 95mA max

    the online calculator says 47ohm, 1W

    Trypwyr what would you suggest for two resistors? Forum says I can always use a higher resistor. So higher on the ohms, or higher on the Watts? or both?

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