Instructables
Picture of LASER pattern generator
laser show_bb.png
2012-01-23 21.53.09.jpg
I have made a small LASER pattern generator using simple DC motors. I had made my first as a kid in school with no speed control what so ever. This one is controlled by an Adruino UNO and L293 motor driver.
 
Remove these adsRemove these ads by Signing Up

Step 1: Parts needed

Picture of Parts needed
switches.jpg
This is a very simple setup. The following parts are needed.
2 DC motors
2 round mirrors
something to mount mirros on to the motor rotor. (a gear head will help)
Adrduino UNO
Power to run the motors 6V AC to DC convertor
Breadboard
connecting wires

Step 2: Making the connections

Picture of Making the connections
pin diagram.png
laser circle.jpg
I had followed a guide to connect L293 D to run 2 motors. I modified the circuit to include speed control.
The attached picture shows how it has been connected. The digram shows how the wiring was done. Speed control was done with PWM via Arduino.
One motor runs at a constant speed of PWM value of 32 and the other ones speed can be increased or decreased via two push buttons. 
When both motors run at same speed a constant ellipse is displayed.

Step 3: Connections and code

Picture of Connections and code
2012-02-07 17.55.19.jpg
We need to attach the mirrors to the motor rotors. For this I used simple gear heads and stuck the mirrors on the top aligning the centers as close as possible. P

Alignment is very important for this to work but a little bit here and there will do

The laser is focused on the motors mirror running with constant speed. This displays a circle on the wall. Now place the second motor in such a way that the LASER bouncing from the first mirror falls totally on the second one. The mirrors have to be very close for this to work.

Switches are to be connected to the Arduino input pins 1 and 2.

A variable stores the value of the PWM for second motor and the pressing of the buttons brings the state to LOW. And when ever this happens the factor is incremented or decremented as per the switch being pressed.

Now connect the wires connect the Arduino the USB and upload the code.
You have inspired my next project.
It was something I made back in the 80's, but it was all analog.
You've given me a great idea on how to make it AVR controlled.

It's going to be awesome if it works out!
Thanks for the spark!
from the looks of the video you need to use power modulation rather than pulse modulation for speed control to take the jitter and breaks away
Mtaram (author)  Cyberscann542 years ago
That is my crappy cell phone camera. Other wise the patterns are very smooth. Will try to record a better one and post.