3 Mirror Spiro

I am going to be building a spiro and I want it to be a non-portable high quality unit. I would like it to produce a wide range of patterns(for a spiro anyways) and a have large projected size on the wall. To get a larger size projection would need to increase the angle of the mirror on the motor? If so should I do that on both mirrors or just that last? EDIT: I think using larger mirrors that are slightly more off center allows for the ability create larger patterns.

Is there a big advantage to going to a 3 mirror spiro over 2 mirrors? EDIT: just found you tube video that showed a 3 mirror, think thats the ways to go for a non-portable spiro.

I am going to order the motors and pots from an electronics site so i need a ballpark on what would be good motors for this project. i know there is a lot of other threads on spiros but most people are putting them in portable packages so they are using tiny motors. Is there any advantage to having high RPM motors(besides the cool sound)? I am going with a 100 ohm pot i guess because thats what is suggested.

EDIT: i guess all i need answered is what type of motors should i order.

Depends on the size of your mirrors, and yes, increasing their angle will give you a bigger pattern. Simple 3-12V hobby motors work great for spiro's and are somewhat easy to control. There isn't much "precision" in spirographs. If you want it to be stable and precise, I would ditch the pots for speed control and go with PWM, you can get much more linear speeds then.

I agree with Things.A PWM circuit or A 317 current regulated circuit works excellent for controlling the motor speeds. there are 100's of circuits on the web that are simple to construct and made primarily for speed control. A RC motor speed control works great as well plus you can connect it to a regular Mabuchi 500 series motor and get good smooth control. There are many to choose from and the motor selection is pretty vast. It's a simple task to mount a mirror on a RC pinion gear and balance it with a dremel. But if you want a rudimentary setup then the single pot per motor as been done with ok results. I've constructed a few and I like the one's made with precision motors due to the fact with a balanced load they are very smooth. Any vibration on the shaft and in turn the mirror, will show up on the projection. Anyway good luck and be sure to post some pics when your done.

Chuck

MISTERWILLING;

Since you are close, I would go to B&G Surplus in Garland and just pickup some 40mm fan motors:

They sell over internet & catalog & don't really have a showroom.

Tell them a good customer said to let you look around.

You can find 12 VDC & 5 VDC in a variety of sizes.

If you can wait a week or so, I can get you some at even less cost.

Your 8X BR pattern should be amazing on a white wall.

Larry DFW

increasing their angle will give you a bigger pattern

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One thing to consider is that with too much of an angle on the second bounce you will get "big" but you could end up with a large hole in the middle of the pattern.

Experimentation is the name of the game.

Regards rog8811

rog8811 said:

One thing to consider is that with too much of an angle on the second bounce you will get "big" but you could end up with a large hole in the middle of the pattern.

Experimentation is the name of the game.

Regards rog8811

Click to expand...

One thing you could try that I did, get a paper and cut it in a circle then put slits with different widths in it for the beam. Then put that on a fan with the blades cut off. Shine the laser in there before it goes onto the spinning mirrors. The cool thing is, with different size slots, you can get really cool effects with the beam like different dashes and whatnot. Also, if you want to be really fancy, put potentiometers on each fan to control speed so then you can get many more effects.

great idea this of puting papers in the mirrors to get pulsed wave :O

Sometimes the bigger doesn't mean the better. With computer case fans you are going to deal with brushless motors, which are controlled by electronics that can't operate at low voltages, so you'll have a limited speed range. They also won't go very fast, only about 3500rpm max. And they are not designed to run with offset weithgts as vibrations affect them and will reduce its lifetime. They have quality bearings designet to produce low noise, an you know, precision mechanisms aren't designed to withstand constant vibrations

The best is coreless motors. They are very cheap, very small, designed to vibrate and they can run as fast as 7000-8000rpm. They also take very low current. And as they have almost no inertial weight, they will start running at very low voltages and operate within a wide range. The rest you need is the lightest first surface mirror you can find. PMMA (perspex) mirror will do the trick as it's lightweight and rigid.

you can buy them here:
http://www.pagermotors.com/Products.php?f_category=Pager

It's better to buy the ones with attached weight. Removing it is very easy. I used a broken 0.8mm drill bit and tweezers. Just take the broken or not broken bit, make a hole in a piece of metal and remove it from the drill, leaving most part of the bit inside the metal. Then hold the motor's weight with the pliers and press the motor shaft to the drill bit until the weight goes off. That way you won't damage the motor nor the weight. Ahm, you can break the drill bit, so better use an already broken one.

and a have large projected size on the wall.

Click to expand...

Then you will have to think about a good way to focus the combined beam (if you're using more than one colour) or else you're gonna have to build it with an easy access to the modules so you can project it where you want (because of focusing distances).

Thanks

Thanks for input so far, can't wait to get this going and shine a 7 color laser through it with some fog.

I will seriously advise you AGAINST purchasing fans for this project. Essentially it sounds to me as if your wanting to actually spend the money and get a GOOD SETUP not some really easy and cheap.

Motors if your not big on teenie (which honestly isn't all that important) can be found at radio shack
http://www.radioshack.com/product/index.jsp?productId=2914699 (yes they are a bit expensive but they are easily purchased)
DX: http://www.dealextreme.com/details.dx/sku.15141
if you succeed in getting 2 this is a good deal. although more expensive than radio shack.

another good thing about those motors is they have screw holes right in the front so you, being a machinist, can make mounts for the motors easily enough.

Once you have the motors you can take gears from cd-roms or other motors and mount the mirrors directly onto the gears. by trying to mount it flush your going to fail, but just enough to give you the angle you need.

for mirrors I've been using the mirrors from dental tools. They are first surface and are round which I think is important so you have more area to bounce lasers off of while it spins. align everything and your golden. I'll provide pictures of some motors I've setup.

Yeah, I use motors from CD readers from computers. They look just like Kryton's post^^. And they've been working fine for me. Also, the other thing you have to consider is, are you going to mount it in parallel configurations, or square? I've personally done square but... in the future I will probably do parallel since w/ square it can be tricky to have no loss/cutoff at the end, especially if you want it big. Also, I'd say you should be fine if you have the last mirror at the largest angle.

And another tip if you want... I usually mount the mirrors with hotglue. I find it works fine in terms of strength, yet is VERY easily changed (just re-heat the glue on there w/ the tip of the glue gun). So.. you could set the last mirror at a big angle (maybe 5-10 degrees) and if you feel the pattern isn't nice or is messed up... change it .

hey kenom. i am getting into making my first spyro but my radioshack was out of motors. the local high school is doing some big group project, just my luck. anywho, so i don't want to mount the mirrors and perpendicular to the motor shaft? i need just slight angle?

you literally want that motor and mirror to be like 95 degrees instead of 90 degrees. In an attempt to try to get it perfectly flat on the gear your going to mess it up and mount it off. That is literally the only angle your going to need. the larger the angle the more difficult it's going to be to get it to shine onto the next mirror.

lets pretend i am a moron (well in this case i am :yabbem when you say 95 deg. is that the mirror mounted to the motor shaft. or the mirror/motor assembly in relation to the second motor/mirror?