Connect with us

Taking a audio signal and driving a DC Motor

Discussion in 'Hobby Electronics' started by Eric, Dec 3, 2004.

Scroll to continue with content
  1. Eric

    Eric Guest

    Hello all,

    I am trying to build something for my deaf brother. I want to hookup an
    amplified audio signal to a small 1.5v - 6v DC motor. It needs to be
    able to speed up when the sound is louder, slow down when there is less
    sound and stop if no sound. It needs some type of regulator or
    something to cut the voltage to a max of 6V DC.

    Can someone help me figure this out? Please help! As I said, this is
    for my deaf brother and I would like to make this for him for x-mas. It
    would make him VERY happy! It would also make my parents happy since
    they get mad at him for turning the volume up real loud so he can feel
    the sound.

    It can be either a stand alone unit with an input from a headphone jack,
    or something integrated into a headphone amplifier. The integrated way
    would be the best but either way will work.

    Thank you very much!


    If you reply by email, delete REMOVEALLCAPS from
    (Stupid spammers force me to hide
    my email addresses)

    Report SPAM to
  2. Phil Allison

    Phil Allison Guest


    ** A bridge rectifier is probably *all* you need ( do not add a
    apacitor) - the AC terminals connect to the speaker line. An extra diode
    wired in reverse from the + to - terminals is worth trying too. On music
    programme, the average voltage will not easily exceed 6 volts.

    ............... Phil
  3. Geoff C

    Geoff C Guest

    Jaycar used to have a subsonic backpack for feeling games such as Nintendo
    etc. It had a small built in power amp and is virtually inaudible. I bought
    one for my kids but they never used it. It only cost about $15 and must
    have been a surplus item. This might be another thing to try.
  4. Eric

    Eric Guest

    Someone said something to me before about a backpack "Shaker" but they
    didn't have any specifics and I couldn't find anything on the web about
    it. I will see if I can find one, but half the fun, for me at least, is
    building something. I thought it might be cool to take the left and
    right signals to motors on his left and right arm. That way he could
    feel where the sound is coming from (ie someone shooting from his right
    would activate the right motor)

    I think that would make him the happiest. Thank you for the imput
    though.. I will look into it as a backup plan if I cannot get this
    thing working in the next few days.

    Thanks again,

  5. Eric

    Eric Guest

    Thanks for the help Phil! Do you think it would be wise if I use an
    audio transformer to isolate the soundcard from the headphone amp/bridge
    rectifier/motor? I have some old Radio Shack audio transformers that
    are 1,000 ohm center-tapped primary, 8 ohm secondary. Do you think that
    this would be ok to use?

    Also, I have measured the headphone amps output and it hits 9.5 volts
    while I am playing one of the games he plays. I know I could turn down
    the volume to lower the voltage but I can't depend on my brother to keep
    it turned down. It would be nice it I could find a way to cap it to a
    max of 6v DC but still allow for the lower voltages so the motor would
    vibrate lighter at quiet sounds and harder at louder sounds (but not
    burn up the motor with too much voltage). I've tried to find a
    vibrating motor (or a weight that I can attach to any motor) that has a
    larger working range but so far I have not found it and I am running
    short on time before x-mas!

    Thanks agian for your help and for any more hints you can provide!

  6. Phil Allison

    Phil Allison Guest


    ** Who said anything about headphone amps ???

    No way one of them can drive a DC motor. A normal speaker amp of a few
    watts output at least is needed - I suggest you lose the speaker and turn
    up the bass for a trial run.

    ................ Phil
  7. Yep, Jaycar Electronics used to stock them but according to their website
    the item is no longer available. However I did find this for you - hope it

    BTW. They work quite well and I'm sure your deaf brother will be impressed.

  8. Guest

    Guest Guest

  9. Eric

    Eric Guest

    Yeah, that is exactly what I am looking for except there is no
    schematic. :( I'm a freshman in high school and wanted to build this
    as a gift for my little brother that is deaf. Does anyone have a
    schematic for this device or a device that would do the same thing?

    Thank you,


    To email directly please delete the REMOVEALLCAPS portion of
    . Sorry, last time I posted my
    email address on a news boards I was emailed a ton of spam and a few
  10. KLR

    KLR Guest

    As I rememeber - they were called "aura interactor". Jaycar had them
    I'm pretty sure - and the way the price kept dropping and dropping
    they must have had some trouble selling them. Maybe they still have
    some lying around.

    Maybe also there might be some used for sale on Ebay too ?

    They had a driver in them similar to a speaker but it had a heavy mass
    of metal in the centre instead of a cone. This would vibrate and
    shake - rather than move air mass as a normal cone speaker does.

    The PCB in it was basically a subwoofer amp with low pass filtering.
  11. KLR

    KLR Guest

    to make a motor vibrate, you just have to add a weight (try using a
    small steel washer or hex nut) but attatch it to the shaft off-centre.
    Doesnt have to be terribly big. drill a small hole for the shaft to
    go in and weld it in there, or just weld it to the edge. sheet metal
    shop could do this for you most likely if you dont have access to
    welding gear

    This works quite well as a "shaker" :)
  12. quietguy

    quietguy Guest

    I am curious as to why you want to use a motor, if it is vibration that you are
    looking for. Had you thought about something really simple like a relay with a
    normally closed contact? Feed the coil through the normally closed contact and
    the relay will vibrate nicely when fed the audio signal through a simple (bridge
    or diode?) rectifier -

  13. quietguy

    quietguy Guest

    Are you aware that there are 'coneless speakers' that you attach to a surface
    (such as a window)? One of these audio drivers might do the trick, just go to a
    HiFi store and ask for a demo

  14. Eric

    Eric Guest

    I don't have any problem finding a motor that shakes, just the circuit
    to drive it from an audio source. I would prefer building it instead of
    buying a whole backpack unit because it isn't what I want. The backpack
    unit is larger and would be uncomfortable to wear. If it was worn as
    designed, you couldn't lean back in the chair. The little motors would
    be pretty quiet (a big plus in my house!) and could attach to his arm.
    This would be ideal for his situation. I'd really like a schematic or
    link for an Audio Signal to a DC Motor Controller. Something like the
    unit at -
    (Thanks Surija for this link).

    If anyone has any info on how to build something that does this
    function, I would really appreciate it!

    Thanks again,
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day