How do I make this thing I came up with?

March 5, 2009 2:40 PM

I had a great idea the other day that would require a little bit of simple programming and engineering, but I have no background in either of those. Basically, I'd like to make a USB device with a little motor that vibrates at several different specific frequencies, determined by the user (preferably through the computer). Where do I even start?

First, is there something out there that does just that?

What programming language would I use? What physical device would I need to control the motor? A transistor? Resistor? Step-sister? Maybe some amps and a watt or two? I don't know anything about any of this, but I'm willing to spend some time figuring it out if the Oracle of AskMe can point me in the right direction.

p.s. this is not a sex toy, I promise

posted by borkingchikapa to technology (7 comments total)

It sounds like you are describing USB computer speakers. That's what speakers do, vibrate at different frequencies controlled by the computer.
posted by pseudonick at 2:52 PM on March 5 [2 favorites]

Probably the easiest way to get going with something like this if you don't have much in the way of hardware or software chops would be with an Arduino, which is programmed with Processing. Get an Arduino board, a pager motor, and a transistor to give you more current. Drive the motor with PWM to change the intensity, and you're in business.
posted by zsazsa at 2:53 PM on March 5 [2 favorites]

p.s. this is not a sex toy, I promise

It will probably be used for one anyway. Anyway, a basic overview of what you'll need to do: a USB-to-serial chip such as the FT232 series, interfaced with a PIC or AVR microcontroller which controls the motor. There are all kinds of resources on the web detailing how to use microcontrollers to control motors, mostly for use by robot builders. You've got a steep learning curve, though, as you're going to need to learn about microcontroller programming at the very least, and probably more basic electronics knowledge judging by your description of your current skill level.
posted by DecemberBoy at 2:55 PM on March 5

p.s. this is not a sex toy, I promise
You'd be too late, anyway.
posted by Thorzdad at 3:06 PM on March 5

Or maybe look into hacking an XBox360 controller, or similar, that already has a USB-controlled shaker motor in it? It almost certainly uses the USB HID class to control the vibration.

But I think zsazsa's suggestion of Arduino is best -- it's pretty much designed for getting beginners started. (Oh to be 15 again; I'd be playing around with that rather than wiring LEDs to my C64's user port...)
posted by We had a deal, Kyle at 3:20 PM on March 5

As a hobby project, the folks above have given you great ideas. Although, I would note that USB programming is not for the faint of heart--not as bad as lots of hardware interface work, but not nice either. Personally, I'd go with a PIC evaluation board, PWM for motor control, and a USB serial emulator. You might look at the ooPIC, as it'll come all wired up nicely for you. But, the Arduino apparently has a much nicer development environment.

I honestly guess that you'll probably spend around four to six months learning to program sufficiently for this project if you have no experience at all. The electrical engineering is pretty simple on this one, although I still imagine it'll take you a few weeks to find the appropriate monkey-see-monkey-do circuits necessary.

If you're trying to build an actual product, you're probably out of your depth. The mass production cost on this thing should be under $5, with a minimum physical size roughly identical to a thumbdrive. With prototyping hardware, it looks like an Arduino board runs around $20--and the smallest is maybe postage stamp sized. I suggest you hire a contractor.
posted by Netzapper at 5:47 PM on March 5

pseudonick is spot on, imo.

Right out of the box, that'll do what you want. Get USB speakers and/or just powered speakers and drive them with Audacity or any of a number of programs that allow synthesis of waveforms and you are in business if you want to do a concept demo.

Of course, vibrating motors can be made to go a lot lower in frequency than speakers, so if you need sub audible frequencies, a motor might be better.

Check out phidgets at http://www.phidgets.com/products.php?category=6

Close to your specs.
posted by FauxScot at 6:24 PM on March 5