DIY PIC based laser spirograph

[AP_Digital_light]

PIC microcontroller based three axis laser spirograph.
Design is quite simple and employs regular parts and components.

Watch it in action:
http://www.youtube.com/watch?v=gxwFzfvi0DY


Some photos from my collection
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[AP_Digital_light]

At first prototype I used blank DVD as reflective material but later I discovered more practical way.
Technology of making FS mirror is shown in my "DIY Front Surface Mirror" video.
http://www.youtube.com/watch?v=RSBBjzttfzo

 

[AP_Digital_light]

Microcontroller PIC18F1320 handles whole routine job.
PIC implements 3 channels PWM generator.
PWM signal toggles MOSFET transistor 2N7000 (Id 200mA). Mirror actuator is connected as load to MOSFET.

As mirror actuator I used 5V 200mA CPU cooling fan. It's easy to mount mirror on its flat side.

Most pointers are rated from 3V to 5V, so I've integrated LM317-based voltage regulator with adjustable output.

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I've modified design.
Device accepts 5V and 12V fan with maximum current 200mA .
Voltage is selected by jumper.

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Notes from the bench(it's not release version. Modification is following):

- schematic;
- BOM;
- HEX;
- PCB;
- PCB in AutoCAD format
- source code for CCS compiler.

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Archive with updated info is available at
http://www.instructables.com/id/SPX5Z9PFCZERCYE/
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For beginners and busy people, programmed chip, PCB or assembled board available upon request.
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[AP_Digital_light]

There are two work modes, selected by toggle switch: manual and automatic.

In manual mode operator controls each motor individually by twisting corresponding potentiometer connected to analog input of microcontroller. PIC constantly reads analog inputs and modifies PWM signal so duty value is proportional to voltage on analog input.

In automatic mode microcontroller employs pseudo-random algorithm to calculate duty value for every motor.
Current duty value is stored in internal EEPROM and used as initial data for next calculation
so microcontroller will generates sequence of nonrepetitive unique patterns for long time.

 

[AP_Digital_light]

Attaching mirror to the motor.
Acrylic mirror is very light, so 1/2'' double sided sticky foam tape will do job.

You can use thick paper as a wedge to tilt mirror. Insert it between mirror and motor.
In my setup, tilt is 2-3 degrees. It results 6' wide pattern at a distance 18'.

It's impossible to center mirror properly regarding motor shaft and even slight offset will cause vibration and noise at high speed, so I've developed some tricks for mirror balancing.

WARNING!!! This method will work only for acrylic/plastic mirrors!!!

At first I've tried to shape spinning mirror with file but fan is low torque device, so even light pressure with tool forced motor to full stop.

Since idea with turning part and fixed tool has failed, I've tried opposite approach -
Dremel with 1/2" sanding drum against motionless mirror, and that's really worked.

Some advices for people who wants to follow.

Motor with mirror must be off.
Select sanding band with coarse grit.
Set Dremel to minimal speed.

Hold Dremel that axes of tool and motor shaft are parallel.
Slowly bring sanding drum to the edge of mirror and press against it. Don't put much pressure. Spinning tool will rotate mirror and file it at the same time.
Take your time, go easy and, if you have enough patience, you'll get perfect round mirror which will run smooth and quiet.

UPDATE!!!
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New tutorial "How to balance acrylic mirrors using drill-press".
http://www.youtube.com/watch?v=8j4HCzs3aXo
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[AP_Digital_light]

Optic setup.

Motors can be placed on parallel lines or form square without one side.

Using square design results more compact device.

Trick for easy adjustment. Use double sided sticky tape to attach motor to base, and after all adjustments, secure motor on place with hot glue.

Adjustment is simple.
Start motors and aim beam that it stays within mirror area at maximum deflection.

As support for pointer I've used piece of wood and some hot glue. Cheap and fast.

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[AP_Digital_light]

And finally - box.
Hammond 8x4.5x2.5.
Aluminum faceplate.
Labels are made using secret military technology of heat toner transfer .

 

[woop]

thats very cool. although surely you could find smaller, faster motors to use.
if i could be bothered, i will make one like it
i did make a 2 axis one the other day, but the motors don't really spin fast enough

 

[BlueFusion]

There are many things about the way you went about this that annoy me very much.
But it's (almost) irrelevant cos the end result is good enough.

 

[chido]

Nice, but it would've been better if you had posted this in the Tutorials section.

 

[AP_Digital_light]

I've seen DIY topics and similar stuff here.
If this is wrong place then highest authority will move it.

 

[CL_]

very cool, i saw that you posted pics from this before, and now we know how to make it

 

[AP_Digital_light]

very cool, i saw that you posted pics from this before, and now we know how to make it

Thank you.
I'm sure, cloning will only improve device.

 

[SargeMX5]

Is that circuit pre-made or you have to put it together?

 

[AP_Digital_light]

PCB is home made, but schematic is simple and it can be assembled on a prototyping board.

 

[SargeMX5]

Where can i obtain a schematic and list of all components to complete that circuit?