In this instructable I will show you how to make a laser spirograph that changes forms automatically, and without the need to program an Audrino. This is accomplish by the use of 3 almost identical circuits that controls the 3 electric motors.
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As you can see in the picture there is one circuit board with the tree individual circuits, three motors (two computer fans and a normal motor) with mirrors attached, and a green laser pointer. I use a laser that has a switch instead of a button, so I can leave it on while I enjoy the show.
Like I already pointed out, in each motor there is a circular mirror. These mirrors are from disposable dental mirrors, because they are already rounded, have a nice size and are easy to work with. The mirrors are glued in a coaxial way with the motor, but they have a small tilt. When the laser strikes the spinning surface of the tilt mirror, it is reflected forming a circle. If this circle is projected into another spinning tilt mirror it will form a variety of shapes, depending on the motors velocity and other factors. Adding a third motor just opens the possibility to even more complex shapes.
If you want to see it in a more scientific way, the resulting shape is the plot on polar coordinates of the following equation: f(r,ø) = A sen (x* ø) + B sen (y* ø) + C sen (z* ø). Were “A”, “B” and “C” are the amplitude that is the mean of how much the mirror is tilt, and “x”, “y” and “z” are the velocity of each motor and the offset between them.
So to be able to change the shape that is plotted you need to change the amplitude, the offset or the velocity. I can’t think of a simple way to change the amplitude, you couldn’t control the offset unless you used stepped motors and that is out of my reach. So what I did was to change the velocity of each motor.
Like I already pointed out, in each motor there is a circular mirror. These mirrors are from disposable dental mirrors, because they are already rounded, have a nice size and are easy to work with. The mirrors are glued in a coaxial way with the motor, but they have a small tilt. When the laser strikes the spinning surface of the tilt mirror, it is reflected forming a circle. If this circle is projected into another spinning tilt mirror it will form a variety of shapes, depending on the motors velocity and other factors. Adding a third motor just opens the possibility to even more complex shapes.
If you want to see it in a more scientific way, the resulting shape is the plot on polar coordinates of the following equation: f(r,ø) = A sen (x* ø) + B sen (y* ø) + C sen (z* ø). Were “A”, “B” and “C” are the amplitude that is the mean of how much the mirror is tilt, and “x”, “y” and “z” are the velocity of each motor and the offset between them.
So to be able to change the shape that is plotted you need to change the amplitude, the offset or the velocity. I can’t think of a simple way to change the amplitude, you couldn’t control the offset unless you used stepped motors and that is out of my reach. So what I did was to change the velocity of each motor.
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I was wondering: would it be possible to make a photo of the back of the board, so that I can check all the connections compared to what I have soldered?
Thanks!
However, for the time being, I'll just mess around a bit and figure out some electronics. Thanks for the tip.
I misjudged the grounds, whereas I thought the ground + and ground - of the TL082 went to the motors, however now I understand that one end of the motor is connected to the TL082 and the other is connected to the NE555, that cleared things up for me.
Hopefully I will now be able to complete the project :)
Thanks again for the help!
PS: I have a simple digital multimeter, with a beep-sound indicating positing to simply check if a connection is good and nothing gets short-circuited.
PS2: somehow I can't reply, but have to type a new comment, because otherwise it gives an error of typing the 2 words.
If you are into electronics you should think in buying a good multimeter (Im a noob and I have 3 different kinds, jajaja). And when you get a little bit more serious you should buy a oscilloscope. There are some fearly cheap on ebay that you plug to the computer with USB and works really nice.
I encountered a problem, what I was afraid of, as being new to electronics.
From what I can tell, all connections are good, I get the + and - 12 and 5v power.
No shortcircuits.
I assumed that the TL082 grounds go to the motors (+ and -), but perhaps I am confused there?
My multimeter says all connections are okay, but the grounds - and + don't have a signal.
Should I apply the +12v and -12 from the power in and loop it to the motors?
Thanks in advance.
You are correct, the motor goes between the output of the 555 and the ground of the TL082. Also, you have to use the ground of the power supply to the ground of the TL082. If you can get your hands on a osciloscope it would be great. Hope this helped.
I'm gonna make a special birthday party for my mother in law who's gonna be 50 soon.
Besides music, I'd love to do something cool with a laser pointer, and came across this build.
I thought I'd give it a go, but my knowledge is very limited towards electronics.
Now, I figured out where to solder all the resistors and capacitors, and the 5v and 12 + and -.
However, I didn't figure out what lead to solder from the TL082 to the NE555 and what the 'fork' symbol stands for (couldn't find it on google, but my guess is it has to do with the 3 circuits connecting each other?).
I'd be very gratefull for any help, and it'd be awesome to get this working.
Thanks in advance!
The fork symbol is ground, and if you see the out signal from the TL082 it is a red "saw", and in the 555 circuit there is a equal red "saw" connected to the voltage control (leg #5). Thats how you connect together the two circuits.
One important point is that you may think that a 12v or 5v supply has in one side + and in the other - and thats not true for this circuit. If you put a tester between the +5v and -5v you are gona measure 10v, and in the case of 12v you are gonna measure 24v. So be clear, the measure of voltage the disgn has is between the supply and ground. I used and very old PC power supply, they usually have the color code in a sticker in one side.
I hope you can build this and have a great time with it, and that your mother in law enjoys it too. Just one final though, for a better result I used a 5mw laser. You can use a normal laser but the room have to be really dark (all lights out).