Hi. I want to a converter device for deaf people. This device will convert the music to vibration. I will use arduino vibration module. But I have a problem. I dont know how I change frequency of vibration motor. I've read so many articles on this topic but I couldn't find anything. I've tried change the volt but didnt work. What should I do? Thanks.
Start by posting your full sketch and a schematic of your project
I found a site in this forum
I want to do something like this but it doesnt working. So I have to find how do I change the frequency of vibration motor or how can I work this circuit
So what does it do ?
To be efficient a vibration motor is tuned to a specific frequency. I dont think it would be easy to change it.
Then can I make a special order? E.g. Can I order a motor with 17000 rpm? Thanks for reply by the way.
They can be given a higher voltage and lower voltage.
You could try a PWM signal, that will change its mechanical rotation speed.
I think it is not allowed to connect them directly to a output pin. They draw too much current and they are for 3V, not 5V.
There are many bad examples at Instructables.
A motor is just a motor. To give a certain frequency you might try some kind of speaker driver without a cone. Like those bone-headphones. There are also mechanical vibration devices that needs to be driven in both direction with H-bridge. I don't know if they have a certain name (solenoid vibrator, electromagnetic vibrator, and so on).
Yeah, how much money do you have? 
When I was a kid, I remember there were slot car motors that would go over 10,000 RPM. But if you put a weight on it to make it vibrate it's going to slow-down (to some extent).
With a regular vibration motor the speed (obviously) determines the frequency. You can slow it down but then you're also reducing power and you can't really speed it up without applying too much voltage and burning it up.
But you've got a couple of other major issues. The inertia prevents you from quickly changing the speed and music contains many-many simultaneous frequencies. Even a single note on an instrument or voice contains multiple harmonics & overtones. It's the harmonics & overtones that give different singers a unique voice even when singing the exact same notes or what makes a trumpet sound different from a guitar when playing the same note. When you add chords & multiple instruments and singers the audio spectrum gets even more complex!
A speaker can reproduce simultaneous frequencies but a motor only has one speed at any given instant.
I'm not sure if you can "feel frequency" in the mid & high frequencies. You might feel something but I just don't know if 5000Hz feels any different than 20,000 Hz (if you can get enough vibration to feel it at all). You'll need to experiment with that.
You might just try a regular speaker cone touching the skin...
You can buy a bass shaker. These are made to attach to a chair, etc. and they will vibrate at the correct bass frequencies in the music. But the physics (mass) reduce the output at higher frequencies, especially when attached to a heavy object (the same reason the mass of a woofer prevents it from reproducing high frequencies). These have to be driven by a fairly-powerful audio amplifier (no Arduino needed).
A deaf person could feel the bass & rhythm with a bass shaker but it might be boring.
And you know... Even a hearing person wouldn't be able to understand speech or recognize a song from vibrations. You could experiment with that (assuming you are not deaf yourself) by putting on headphones and playing white noise or pink noise to drown-out the sound while you feel the vibrations through your skin/body.
Thank you but I'm still don't know what should I do. I really couldn't understand how to use the bass shaker. Could you please explain again?
And do you mean this project is impossible?
Thank you but I've already tried this but couldn't get any results
Also thanks for this. I'm going to think about it for a while then I will writing.
How much do I need? 
You might want to experiment and see if a deaf person can feel the vibrations from a speaker at high volume - after all the whole purpose of a speaker is to convert an electrical signal at audio frequencies to vibration. I don't think there is any way you will get a vibration motor to work well at 17000 Hz, even a mid-range speaker is not very efficient at that frequency because of the mass of the speaker cone.
I detect you are not working with any deaf people for your project.
Back in the day when telegraph was first invented, deaf people could use it because they could feel the sounder vibration with their fingers. With the invention of radio, they could feel the sounds by resting their finger on a speaker. With amateur radio, they could receive and send code the same way.
There is likely a school for deaf in your state, like mine. Go talk to some of their people.
Good luck, Paul
Thank you for reply. I understood but speaker not too loud? I mean if I decrease the volume then vibrations will decreasing too. As far as I know there is no way to lower the volume and increase the vibration at the same time. Am I wrong?
Thank you Paul but I don't live in America so there are almost no deaf schools in my country and I don't know any deaf people. That's why I don't work with them. But if I can make a device close to my purpose then I can spend all my time looking for a deaf person. I just want it to be worth it.
By the way, you will ask me, are there deaf people in your country? I'm sure there are but how can I find? Let's say I found what will I ask them? I mean there's no point in talking if I can't give them a device.I hope I was able to explain myself thank you again.
Rest your fingers on the outer edge of a paper speaker cone. Apply sound. If you can feel anything, then that is what a deaf person will feel and is much more sensitive to the feeling that you or I can be.
Not too long ago I saw a video about a young lady who was totally deaf, but she taught herself to sing and that she did perfectly. She used her smart phone to show the frequency of the sound she was making, while she felt the jaw bone with her fingers. That way she learned to make the sounds of each musical note. Put together she can sing better than a hearing person.
To find a deaf person, go to a large hospital in your area. Tell the administrator about your project and ask for their help in finding someone to work with you in your project.
Good luck, Paul
Yes, you are wrong. The volume depends on coupling the vibration to the air. That's why loudspeakers have cones. So by cutting off the cone you can greatly reduce the audible volume whilst still allowing the vibrations to be felt.
This could be quite an interesting project, but I think you will have to do some basic research. Try a few different types of vibration motor. Try cutting up a loudspeaker. Try making your own transducer with a coil of wire and a magnet inside it, connected to a pad the user can feel with their fingertip.
You will probably need to experiment to determine a realistic frequency range. I'm pretty sure our sense of touch operates over a range of frequencies considerably lower than what we can hear. For example, it is easy to feel a 1Hz vibration, but that is well below the audible range.
One approach might be to divide the incoming sound frequencies by (say) ten before presenting them to your transducer, thus making them more "feelable". Perhaps you could provide several transducers - one for each finger - and divide the frequencies between the different fingers. "Haptics" is the name of the game, and it's fascinating.
Back to your original question - I have a question for you: is there an actual need or demand for such a device?
Instead of coming up with ideas to help deaf people, it would be much better to ask deaf people what they want.
I can't believe I didn't think of this. I'm sorry to bother you. Thank you so much.
That is really good advice I will research this too thank you so much.
You are totally right. But, imagine you are born deaf. People listen to music but you don't even know what it is. Even if you want to learn it, the only thing you can understand is rhythm. Even if you can sing, you can't feel it. I think deaf people should be able to experience music too. What do they lose?
Oh, you are SO wrong about that. In the 1970's, in the punch card time, I worked for a computer service bureau that had several dozen deaf young ladies operating the key punch machines. Most all of them attended a deaf church. My friend Dean, lived close by the church and remarked about their singing. Not all on key, etc. but they all loved to try. You don't need ears or hearing to hear music.
Paul
My point is, do you honestly think you are the first person to think of this? That is why you must speak to people in the deaf community - they may already have solutions for this; they may already have tried something similar and found it doesn't work.
It is patronising to assume deaf people are all wishing they could experience music, when you aren't deaf yourself. At the moment you have no idea what their needs and priorities are. That's why you really must engage with them, and ask them. And why would you assume that deaf people aren't capable of using an Arduino to develop something like this themselves?
You are also assuming all deaf people are born totally deaf. Never the case. I am high frequency deaf. Kept me from Viet Nam. But I can hear low frequencies super well.
My #3 Grandson is marrying a young lady who was born premature. Her cochlea did not completely fill with fluid. Eventually she will be deaf in both ears. One is bad now. She is studying American Sign language in University so she can work with deaf children.
A ham radio friend's wife is partially deaf and has to watch your face to understand what you are saying. At a conference a few years ago, we had a group dinner and some of her deaf friends came to dinner with us. They sat next to me and we could converse, but I was continually reminded to face them. They could hear, but not understand the words because of limited frequency hearing.
So, deaf never means TOTALLY deaf, or very rarely so.
Please expand your horizons to a totally different world.
Paul