I Have to calculate a resister for Vibration motor, is it calculated differently than LED's? Thanks!
I Have to calculate a resister for Vibration motor, is it calculated differently than LED's? Thanks!
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.
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!
Last edited by setelf3of5; 09-11-2014 at 09:38 PM.
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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