A previous article discussed the theory behind why running multiple eccentric rotating mass vibration motors synchronise. Today we have uploaded a short video showing the results in practice:
It’s definitely worth noting some of the constraints before using this as the foundation for a design.
First, the motors have to run at the same speed. This is more difficult than at first glance, even small manufacturing tolerances will cause a difference in RPM. Powering the motors at the same voltage is not guaranteed to work.
Secondly, there needs to be enough displacement for the two eccentric masses to enter the same phase and prevent them from jumping out of sync. This means that larger, lower frequency motors are required. In addition, target masses that are rigid or tightly fixed (like a touchscreen) may not work.
Hopefully, you enjoyed the video, if you’d like to see other aspects of vibration motors in action let us know!