Laser Galvo - Arduino Controlled

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Introduction: Laser Galvo - Arduino Controlled

Arduino controlled laser galvo. The servo driven mirrors steer the UV laser leaving a phosphorescent trail on the glow-in-the-dark vinyl sheet.

Originally posted on notes.robives.com

Step 1:

Starting with a sheet of luminous vinyl from eBay and a UV laser pointer. Waving the laser pointer round on the vinyl leaves a persistent glowing trace, just like an old style cathode ray tube. Fun, but even better if we can computer control the laser beam!

I’ve come up with a hardware platform that I hope will let me start simple but then experiment with more complex ideas.

Step 2:

I’m using off the shelf servos driven by an Arduino to steer the beam from the laser.

There are two servos, one for the x axis, one for the y. I’ve attached a small circular mirror tile to the servo.

Step 3:

This stand is made from 3mm laser cut ply – there is a pdf of the parts attached - glue the pieces together using PVA glue.

Step 4:

The servos are clamped in place rather than gluing then to make it easy to make small adjustments. These are cheap off the shelf clamps from Wilkos in the UK

Step 5:

All the parts fit together like this:

Step 6:

…and the servos are connected to the Arduino board. I’ve used pins 9 &10 for the servo control lines.

The code for the arduino is attached

Step 7:

Here’s the code in action.
Next step, I think I’ll have a go at a simple raster display.


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You don't need servos. Just put a boron super magnet in the center of the mirror and hang the mirror and magnet by a two axis gimbal using nylon monofilament sewing thread inside a three axis Helmholtz Coil volume.

A Helmholtz Coil is two identical coils, in series, spaced a distance apart equal to their radii. The coils produce a uniform magnetic field in the space between them and can cancel out the Earth's magnetic field. Vary the Helmholtz coil current and make the mirror dance.

P.S. - With a quick Amazon search, I can buy a 1-axis Helmholtz coil for a thrifty $400. Not something an average hobby experimenter plays with for a toy. If anyone owns these coils, I'm sure they're probably also using something bigger then a dollar-store laser diode pointer.

You have link to a more detailed description or visualization to the mentioned setup? Thanks.

Some years ago "Scientific American"'s Amateur Scientist series had an earth field magnitometer (I know the spelling is wrong) that used a Neodymium Iron Boron magnet to measure changes in the Earth's magnetic field. The magnet was glued to a mirror made from a microscope slide cover glass and mounted on a horizontal nylon monofilament thread mounted on a 'U' shaped support that hung from an other nylon thread. The Helmholtz Coils nulled out the Earth magnetic field so that only changes in the field would move the magnet and mirror. A laser pointer was reflected off the mirror and on to a scale so that changes could be read.

The Helmhotz coils are interesting. thanks for mentioning that. I was looking for a way to steer a laser beam for raster and vectoring images. It would take a bit of effort to calibrate the size of the magnet, center the mirror & string with the array of current drivers on that field. The software to drive the field is complicated enough just to angle x,y precisely - and has to factor corrective signal for the inertia of the magnet/mirror on rapid movements.

I found that article here:

https://metodosgeofisicos.files.wordpress.com/2007/04/0199106b.pdf

There's also this showing another galvo project http://elm-chan.org/works/vlp/report_e.html

Pretty cool, but why don't you just have the servos move the laser pen instead of 2 mirrors?

The laser has more mass & weight then the mirrors. The greater the mass, the more difficult it is to control and stabilize, change direction, etc...

I moved the mirrors rather than the laser as they are very light weight and therefore faster to move.