Instructables
Bouncing a laser beam off a mirror rotating at any angle above 0 degrees will create the illusion of a circle to the human eye. Combine two rotating mirrors, and complex shapes begin to emerge. With every additional mirror, the perceived image becomes more complex and intricate, with the ability to create some very beautiful and bizarre flowing patterns of light.

Most laser spirographs consist of only two mirrors, limiting the complexity of their shapes for the sake of easy construction and bulky size. I have seen various guides on the net about three mirror spirographs, and after creating one figured I would up-the-ante: a four-motor spirograph in a compact box which is portable. This design will accept the use of any pen-style laser pointer, and through the use of potentiometers (variable resistors) to adjust the rotation speed of the mirrors, new shapes can be created. The benefit of using a laser beam allows the image to be projected to any size, on an indoor wall, an outdoor tree, through a lake/pool, snow, or the side of a building.

I hope you enjoy creating and sharing this display of light, which myself, friends, family, and strangers alike have been drawn to the limitless shapes created through exploiting human persistence-of-vision.

This is a rather complex mod. I'm already assuming you know how to solder, and have some basic understanding of wiring. Though you definitely could complete this mod as a first project, it will be rather confusing and challenging.




This violet projector made by user JoeMonkey from following this instructable -- Awesome job Joe!



***WARNING - SERIOUSLY, I MEAN IT, READ THIS ONE***
Laser light while very enjoyable can be extremely dangerous, dangerous to the point that most people don't understand the numbers of how powerful 10 mW (milliwatts) is, much less 100 or 500. While many projects have unnecessary warning labels, the concentrated energy from a laser beam really can blind the eyes of those who look into it's beam. Realistically, any laser with a power over 10mW (3.84mW is the power at which human eyes begin to be damaged) shone directly into a persons eye will de-nature (boil/cook) the rods on the back of their retina. This becomes a big problem if a person looks directly at the beam, as their center of vision will be damaged, inhibiting reading and other fine viewing permanently. The damage comes because the lens of the eye focuses light so precisely, what was 10 mW ends up becoming 80mW since it's focused on such a small area of the retina. It sucks to have your vision ruined for life for a toy. That being said, the cheap crappy red laser pointers for $2 tend to output about 0.5mW, and won't ever hurt you.

Second, don't shine a laser at anyone who doesn't want one pointed at them. In multiple states pointing a laser beam at a person is equivalent to assault with a knife. Many people have an irrational fear (thanks to being portrayed inaccurately in movies and television) that a laser beam is associated with a firearm, as such ignorant people fearing for their life can earn you a trip to jail. This includes pointing laser beams through people's windows, their car, or even simply near them, people are fearful.

Third, never point a laser beam at any aircraft or helicopter. These vehicles often use polycarbonate for their window "glass", and a laser beam anywhere on the window will scatter through the entire surface making it impossible to see out. Pilots take laser beams very seriously, and the government crackdown in the United States is especially strong. I personally know a friend who has been given a $1,000+ ticket and criminal record for pointing a 5mW laser at a police helicopter. Though the real life danger for pilots is minimal and over-hyped, government over-reaction to laser beams is not.

Fourth, eye damage from lasers usually happens without a victim immediately recognizing anything ever happened. A single flash from a 100mW might make you flinch and say, "Wow, that was lucky". In reality, you just toasted a line across your retina, but other parts of your eyes will compensate your vision to the point you don't notice. With multiple exposures (though really, a single 200mW+ exposure will truly screw you up), eventually the damage will accumulate, things become blurry, and you can't read.

Now with all the scary stuff out of the way, let's get to building!
 
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NeilF111 days ago

Busy looking at doing this project I did a basic prototype and it is working brilliantly. However I had a question about the laser duty cycles. Most of the laser all have a 3-5 minute on duty cycle and then a 30-60 second off duty cycle. Now from my understanding this is due to heat build up in the diode. How did you handle this? Is it possible to perhaps extend this duty cycle with a attached heat sink?

QuackMasterDan (author)  NeilF18 days ago
Major kudos on the project, glad you have made excellent progress :-)

You are correct, most laser diodes have a duty cycle of under 5 minutes, after which the need to cool down. The heat may not necessarily be conducted to the diode housing, the heat is stored internally. Too much heat weakens ("cooks") the diode. Fortunately, most laser diodes come in a metal housing that can be removed and attached to a heatsink. The higher power the laser, the quicker it cooks/degrades.

A heatsink with a FAN is the most common way to extend the life of the laser. Purchasing a laser heatsink tends to be fairly expensive. The best solution I've found is either a) mini-motor heatsinks, or b) CPU heatsinks and boring out the center to the diameter of the diode housing. You WILL need a conductor between the diode and its heatsink, just smother the heck out of the diode and heatsink with thermal paste. The other good option is to purchase a laser in which the structure itself (handle that contains the battery) is metal and acts as a heatsink. Lots of surface area! With a CPU heatsink w/ fan, I would feel comfortable using up to a 250mW laser for an hour or two. With that said, ANY laser should not be run indefinitely, no matter how good the cooling system.

This is by no means technically correct, there will always be degradation when a laser runs for an extended period of time, but in practice, if the laser is under 100mW you don't need to worry about duty cycles if they are shorter than 20 minutes. Duty cycles become dangerous to the point of frying diodes when high powers are involved, or for extensive amounts of time (think measuring in hours for a continuous night-time display).

Hope that helps, and thanks for asking!

Ok so at least I was thinking along those lines. On another note I have managed to find a way to almost perfectly mount those pesky mirrors to the motors. Some balsa wood with the front cut at 1-2 degree angles and the laser projection is much much sharper and defined. Will put together a video for it once I have refined the technique a bit. Never thought my wood working lessons from my Grandfather would be so useful in this project. This project has sparked something in my 5 year old daughter and we are now having science lessons everyday so I can explain to her how things work. Wish I could see through her eyes for a moment as this appears completely magical to her. Thanks for the reply.

ananda12 years ago
How would one integrate a spirograph into a party SAFELY? Would you aim it at the air, a wall, the ground? Lawyers are expensive.

As long as the laser beam is moving ("scanning," in the parlance of lasers) there is no danger to anybody's eyeballs. Even the relatively dangerous green laser (as opposed to the common red, and I'm only talking laser pointers here, mW-wise) requires over 1/4 second exposure to the direct or reflected beam, and this just doesn't occur with the laser point whipping by so quickly that it appears to be a line. :-)

jtovar931 year ago
Hi all,

I want to do this project but I can not find 100 ohm potentiometers, the only ones I am able to find are 100k (which atre not the same, right?)
I would be very happy if someone helped me out on this.
agr00m1 year ago
I've actually had this one finished for a while now based off this project. I think it turned out very well. I'm in the design phase of making a 2nd "smarter" one that utilizes a micro-controller. This way I can use it to PWM out to the motors (through a motor driver) to get consistent use each time, have a digital display showing the speed of each motor and have the ability to save pre-programmed designs as well as have a random mode that just does random designs. I'd also like to implement a speaker to so it interacts somewhat with the music being played.

Here's a demo: https://www.youtube.com/watch?v=MXodmgpdcgA&list=UUDADfKyYBMH_d9r3L4t3-8A&index=6&feature=plcp
Hi! I'm doing this spirograph as an honors project for physics II. (Thanks for posting it, btw) Your instructions are written beautifully and I have learned a great deal about parts, tools, and methods while making this. My goal was to learn how to solder, which I have... but also a whole lot more!

Anyhow, my only stumbling block has been in placing the motor-mounted mirrors. Could there be an easier way to place them in the box other than hot glue? I find the need to adjust them as I work down the line and pulling them out gets messy and risks knocking off a mirror each time. My professor suggested that I use air dry clay (which helped with the slight z-axis angle from the cone shaped projection) but when it dried and I went to glue it permanently down... it moved out of the desired position.

I really knew nothing about any part of this kind of thing when I chose to do this. I had a drill, hot glue gun, and pliers when I started out, lol. :) This has been a fun and rewarding experience so far... I just want to play with it now! Do you have any suggestions for me? Should I trace around the bottoms of the motors in the box to help line them up? Maybe there is a defined angle arrangement that always works? Will they automatically line up if I'm playing "Dark side of the moon"? (wouldn't that be cool?) I usually miss the most obvious things... thank you so much for any kind of input you have!
QuackMasterDan (author)  mechanicalities2 years ago
If you wanted to make it a bit easier on yourself, you can try using 40mm Case Fans from newegg. They're dirt cheap, but they run at 12v instead of 3v like hobby motors. Much, much easier to align and work with, but they're bigger. You can throw a folded piece of paper or a shiv underneath the mirror, and have a nice, stable surface to glue it to. I've seen someone put a mount on them and bolt them from underneath the base whenever he needs to move them.

If you want to adjust a mirror because you glued the motor in the wrong spot. Throw the box in the freezer for a good 20-30 minutes. Then with wide-grip pliers, grab and do a rapid twisting motion. You'll very easily and cleanly snap off the hot glue =].

For mounts, there is an absurd amount of RC Airplane mounts for 3v hobby motors, they're semi expensive though, like $5-8 per motor, but, they're solid. I'd definitely mark where you want to put them with a sharpie.

I made a picture detailing the *ideal* layout if  you have enough space. I hope it helps.
pewpewpew.jpg
I looked at those case fans and they look like they will greatly ease my troubles. I like having something solid to glue the mirrors to and a shiv sounds much nicer than my inexperienced eyeballing ability. You are a genius! I'm ordering them today. Also, I'm using 100ohm 2W pots for this... will I need to add a resistor or something since the fans are 12V? Might it limit my shapes or shake off my mirrors if I don't?

I hadn't thought to put the box in the freezer either, so thank you for that tip. I have quite a bit of glue residue that I can now eliminate. :) I look forward to trying your 108 degree ring out too. I think my conduit box is larger than the one you used, so I might have the room to have it work. It will be way more easy to mark the fan placement than it was ompared to my lumps of air dried clay.

I'm really glad that I asked here about this... you've made my day! Thanks again for your help.
I DID IT! It's done. Thank you so much for your input, again. I needed to keep thinking it through and your response encouraged me to do so. :)



I didn't have time for the case fans to come in from China before I needed to turn in my project, so I had to improvise. I took some wick tabs from the bottom of cheap votive candles and soldered them to the tip of the motor. That gave me a solid surface to glue the mirrors on to. Also, the tabs are somewhat flexible and I could adjust the tilt after putting them on. That enabled me to use Lego's as the motor stands, since my tilt wasn't so large.



I'm really excited about this working, it is the most intricate project I've ever made and EVERYBODY loves playing with it! I have to let my teacher keep this one and I've already started my second one (for me to keep). I'm trying your 108 degree model and it really seems to be working great. You have made the the envy of my pre-engineering classmates, lol. I'm already enrolled in the fall electronics engineering program, after enjoying this project so much. Thanks for the help and the inspiration, man! :)
QuackMasterDan (author)  mechanicalities2 years ago
Glad to hear it worked out so well, that's a major reason I write these guides, is to encourage others to push themselves and have fun learning. Not to mention the often very-cool projects they tend to be ;D.

If you really want to have fun with it, use it outside on a foggy night, or throw up some dust or make smoke and fire the beam into it. We've had a few campfires were people have fun pointing the beam up into the rising smoke, and it's pretty mesmerizing.

If you make anything that's cool or a video or have pics, please show them to me. It's always neat to see the work of others, often you guys tend to improve upon my designs in ways I never would have thought of. Keep up the great work!
Electorials3 years ago
Really awesome!

I made this one, and it works perfectly!
It makes some really nice pictures, like rotating 3D shapes :)

The only problem is that the hot glue doesn't hold the mirrors when they're rotating really fast.

Great project!

Thanks
I made the spirograph just like your instructable, only the lay-out is different.
It seems to work really great now! the glue isn't a problem anymore ;)

Thanks for the instructable!

i found the area around 2:30 to be particularly awesome.
QuackMasterDan (author)  Electorials3 years ago

Excellent work! I love hearing that my guides have helped other users, and it's especially exciting when you guys modify my designs! Thanks for the video too, your projector turned out very nice. I hope you get to share your creation with many friends and onlookers, and maybe enlist a few more modders into the laser-building ranks. Keep up the good work, if you make anything else cool, send me a PM, I'd like to see it.
Hello,

What do you mean with "laser building ranks"?

And I'll let youknow when I make something new ;)


Greetings,

Electorials
Just got mine done and posted it today!
http://www.instructables.com/id/4-Motor-100mw-532nm-Laser-Spirograph-Budget-Build-/


Thanks for sharing your's with us!!!!! It was the push I needed to get one built.


I think I've been hit by the laser bug and hard at that. Over the past 3 weeks I've been preoccupied with all aspects of the working laser...Ive purchased The Arctic 3 by Wicked Lasers and several turnkey laser projectors and scanners by American DJ. With that being said It's no surprise that I must build one one now. This project is great and just what I was looking for as a my standard for this first attempt. Please, I'm open for any and all suggestions that may help me actually achieve this
Thank you and look forward to being a part of this forum.
Regarding how to adjust the wobble: do a google search on "harmonograph" and see if that gives any helpful pointers.
would this instructable work with a dollar store laser pointer? very cool project and i am considering builing one of my own, thanks!
QuackMasterDan (author)  jackattack1552 years ago
Will it work? Yes. Will it be as stunning and easy to see? Unlikely. If you're going to spend ~$20-100 in parts, spend a little for a nice laser, even a $10 5mW is a huge step up from the 0.25mW dollar store lasers.
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Heh, only after my ignorant first post did I notice your second XD. That's brilliant, moving the motor itself rather than the disc. You would need some very precise motor to just barely move it along it's slide-rail. I forsee it being a rats-nest of wires and rails and actuators, prepare for a large build. Again, I imagine it will turn out very cool.
The direction of wobble does matter, as two mirrors running opposite to one another cause extremely rapid jumps across the plane of each mirror. The speeds are so high, that you're just going to want a beam that reflects in whole off the final disc. Just get your angles precise, and if you want to shift up things, reverse the direction of a mirror.

As far as getting the angle of the mirror adjustable, I don't think there is any product you can purchase for this. Maybe CNC mill some insanely difficult gearing with a servo attached, but it just doesn't seem practical. If you want precision, you can use a computer fan, with a mirror mounted onto the center of the fan-disc, and use shims to raise the angle to the desired height.

Keep the free thought flowing! I hope that helps. If you ever do figure it out, please let me know, I would be interested to see it.
Regarding your excellent safety warning: Some years ago (15? 20? more?) I very foolishly decided to look inside the laser checkout window at the grocery store checkout and get a closer look at that pretty red laser. It was the briefest flash I could manage and within the first half-second afterwards I realized "That was really stupid." The blackout spot in the middle of my eye was, fortunately, just a small spot that eventually healed, but it took over a decade.

ALL PERSONS DEALING WITH LASERS IN THIS OR ANY OTHER INSTRUCTABLE SHOULD TAKE THIS WARNING WITH THE UTMOST SERIOUSNESS!!!
Standard22 years ago
Could I get away with using glass mirrors instead of acrylic?
QuackMasterDan (author)  Standard22 years ago
Glass should work just fine. Be aware that glass is quite a bit heavier than acrylic, it might require more support.
Do you mean I should put more weight on the opposite end of the motor?
QuackMasterDan (author)  Standard22 years ago
I mean to either a) use epoxy rather than hot glue, which is very messy but very strong, or b) use a 40mm computer fan as the base rather than a 3v hobby motor.
Revonok2 years ago
Followed your design and it came out amazing! Thanks for the great guide.

im looking into building an 8 mirror RGB verson of this. i tracked down affordable front surface mirrors in the form of #3 dental mirrors (20mm). they come in a pack of 12 for roughly $20 on the good ole flebay. just gotta remove them from their holder/backing without breaking them. ill be using a 200mw green, 500mw red and 400mw UV in this.
sitten_duck2 years ago
Do you have to keep turning the knobs to get all the variation in the patterns, or does the variation occur naturally as the spirograph is allowed to run?
QuackMasterDan (author)  sitten_duck2 years ago
I am physically turning the knobs to adjust their speed. To have the spirograph run on it's own would require programming an arduino to use pulse-width-modulation with the motors to vary the speed, which is pretty complex.
Awesome, thank you for your reply. I'm planning on building one based off of your design. I thought about adding an additional mirror at the end, but instead of attaching it to a motor, attaching the mirror to some type of membrane that's been pulled tight across an opening in the box opposite the projection window. When set next to a speaker, (I'm hoping) the sound waves would cause the membrane to move back and forth causing the projection to shrink and expand, pulsating with the music (or at the very least have some type of interesting response). Do you think it might work?
QuackMasterDan (author)  sitten_duck2 years ago
If you want to go that method, you would likely use mylar film. The reflective stuff is annoying and expensive to get though, though the cheap stuff can sometimes be found in electrostatic bags for electronics

If you want sound reactivity, the easiest method would be gluing a mirror directly to a speaker. It wouldn't make a clean expand/contract image, but it would shake it's vibration according to how strong the bass is.

Just an idea =]
monishgogri2 years ago
Can I make the same with a CD / DVD Drive Laser diode?
Thanks in advance, :)
QuackMasterDan (author)  monishgogri2 years ago
Yes, using a DVD+RW laser diode works pretty well. However it takes a lot more than just the diode to make the laser turn on, circuitry is needed to control the voltage and the amperage given to the diode. Laserpointforums.com has guides on how to build a high-powered laser pointer/module using a diode from a drive.
Thanks a ton ;)
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