Hi! I am running a school project using a vibration sensor and a vibration motor. Basically I would like the arduino to receive the analog signal from the sensor and make the motor vibrate, vibrate at the same frequency received by the sensor, but, I looked for articles on the internet and found nothing related to this type of programming, if you can help, I will stay extremely grateful.
(Sorry for my poor english, I'm Brazilian).
Your post says "impedance matching", you might get better answers if you change that to something more accurate, like vibration sensor and vibration motor.
Quite a lot depends on what kind of vibration sensor you use, and of course about your motor. Does your sensor or software give vibration frequency.
Try making a sketch which prints output from your sensor and runs your motor.
This might be harder than you think....
What kind of signal/frequency do you have coming-in? i.e. A constant sine wave, square wave, or pulse, is easier to analyze than an audio signal that has multiple-simultaneous frequencies. Or if the frequency changes quickly the inertia of the motor will make it hard to keep-up with the changes.
And what's the frequency? You reduce the speed but you won't be able to go faster (higher RPM/frequency) than the normal vibration frequency.
A "standard" vibration motor is simply a DC motor with an offset weight and the frequency depends on the RPM. Once you have a motor driver you can easily use PWM to adjust the speed but for a precise RPM you need some kind of sensor to measure that RPM/frequency in a feedback loop (software) to control the speed accurately.
You'll probably have to switch back-and-forth between measuring the input frequency and the actual motor frequency but that's probably not a big deal since the motor can't change speed instantly anyway.
...If it IS audio, or in the low-audio frequency-range you can get a bass shaker which is essentially a speaker that's coupled to a surface or mass instead of using a speaker cone to "move" the air. Those work with a (high power) amplifier so you don't need a microcontroller or software. (You might also need a preamp depending on your "sensor".)
Hi,
Welcome to the forum.
Please read the post at the start of any forum , entitled "How to use this Forum".
OR
http://forum.arduino.cc/index.php/topic,148850.0.html.
What is the application?
What is the source of your vibrations?
How will you know the vibration frequency of the vib motor without some feedback from the vib motor?
You may need two vib sensors, one to measure the source you want to sync to and another to measure the vib motor so you can get its vib frequency the same as the source.
Tom... 
TomGeorge:
Hi,
Welcome to the forum.Please read the post at the start of any forum , entitled "How to use this Forum".
OR
http://forum.arduino.cc/index.php/topic,148850.0.html.What is the application?
What is the source of your vibrations?
How will you know the vibration frequency of the vib motor without some feedback from the vib motor?You may need two vib sensors, one to measure the source you want to sync to and another to measure the vib motor so you can get its vib frequency the same as the source.
Tom...
Hey bro, thanks for the help, it means a lot to me. I'll try later to make a sketch of all sensors and motors, thx. : )