Stepper controller

Nice ink..

Sorry to sound like a downer, but if you are a 'total novice' you are uout of your dept. I'd suggest you build the circuit shown in the link, just to get a feel for the devices, and then try and build up from there.

Del

Nice spelling Del

OK search "laser galvo" +controller

http://www.google.com/search?hl=en&q=%22laser+galvo%22+%2Bcontroller&btnG=Google+Search

loads of hits.

drill there.

repeat in images.'

http://images.google.com/images?hl=en&q=%22laser+galvo%22+%2Bcontroller&um=1&ie=UTF-8&sa=N&tab=wi

lots more visual hits.

The guy on ebay may be wrong if you want to get smooth lissajous figures you need to control the pair in integral multiples of each other. 36 degree jumps sounds iffy to me for what you want.

what they usually do is use voice coil galvos against centering springs then audio tones you vary work well. Compex scenes can be rendered.

http://www.google.com/search?hl=en&q=%22voice+coil%22+%2Bgalvo

and the same as images ius

http://images.google.com/images?hl=en&q=%22voice+coil%22+%2Bgalvo&um=1&ie=UTF-8&sa=N&tab=wi

this gives you a wealth of drill downs

http://en.wikipedia.org/wiki/Lissajous_curve

Your link points to a pair of cheap low-resolution (36°/step, 10 steps per revolution) stepper motors with mirrors attached. That's hardly a galvo!

A galvo refers to a galvanometer - a device that has a very light rotor held in its center position (in the absense of electric current) by a very light spring, usually spiral. A current will rotate the rotor by an amount proportional to the current, and in a direction dictated by the polarity of the current. A galvo scanner has a tiny mirror attached to the rotor so a light beam will be deflected by the mirror. The operation is much like a loudspeaker, except that it is rotary instead of linear, and it can follow a signal having thousands of variations per second, and tiny variations in the current make tiny variations in the deflection of the light beam.

In their simplest mode of operation, stepper motors move one step (36° in the case of the motors shown) whenever the polarity of the current flowing through one of its two windings reverses. Since a reflected beam of light rotates through twice as many degrees as the mirror reflecting it, the smallest angle of deflection you can easily obtain with the motors shown is 72°. Small changes in electric current have absolutely no effect on a lightly loaded stepper motor, and for such a low-resolution motor, you would be lucky to get 100 steps per second. They simply are not appropriate for the job you want them to do.

As Del suggested, you have a lot of learning to do. Start by experimenting with something simple: attach a couple of tiny mirrors to a pair of flexible strips, with one end of each strip fixed on the rim, and the other end glued to the center of a small loudspeaker. Drive the speakers with music (left and right channels, or through high- and lo-pass filters) or audio oscillators. Arrange a pen laser so it points at one mirror, and arrange the second speaker/mirror so the beam reflected from the first mirror strikes the second, then play!

Have Fun!

This is dirt cheap and simple for operating the motors in a +/- half step.

Do try it with a surplus amplifier...

Off the shelf solutions would cost many, many times more than the motors.

You should be able to find some free or cheap software to generate the arbitrary waveforms from your computer sound card.

Hi Kev,

If You want to do raster scan like you see on a CRT it will require much faster real galvos and blanking (modulating the laser source I.E. Analogue or digital TTL ).

Unfortunately stepper based galvos are analogous to getting a Chihuahua when you really need a German Shephard or a Doberman dog to do the job.

Try learning a bit by visiting " www.laserfx.com " then join the group of amateurs and Pros at " www.photonlexicon.com ".

Good luck & Happy New Year