A Linear Laser Brush for Painting With Light

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About: I'm an Italian freelance structural engineer, graphic designer and photographer, and I'm teaching physics in Waldorf schools. I always investigate electronics, robotics and science in general, I'm a passiona...

Intro: A Linear Laser Brush for Painting With Light

If you love photography and experimenting with special effects you will be happy to know that with a very simple circuit and a cheap laser you can easily build a sort of laser "scanner" to take impressive photos and portrait.
My project was born from a more complex automated laser scanner idea, and I decided to build this cool gadget so that you can give vent to your creativity.

Step 1: Laser and Instructions

This is a very common laser but its head projects a line, not a dot. You can easily find a red laser line on ebay.
I thought that if I was able to generate a pulse on that laser and I could set the frequency at my choice, the persistence of vision of photographic techniques should let me create many beautiful effects. Just turn flashing on and move your laser beam during the long exposure of the photo.

Step 2: The Pulse Circuit

As usual I decided to use a simple and common NE555 IC. I know that this famous chip is very effective in making a square wave with personalized frequency and duty cycle.
There are formulas to determine the right resistors and capacitors values to obtain the required features, but here we just play a bit with the powerful java Falstad circuit simulator.
Here is my Test circuit (click to open it), but you also can find many examples on Falstad website.
 


You will notice that changing the values of components (on the falstad window right click on components and choose "edit") the frequency and duty cycle change.
With the values in the picture I obtained a 12Hz frequency and a very short pulse width (actually the wave is reversed, due to the PNP transistor). Then I replaced the 100K resistor with 100K potentiometer plus a 2K resistor; that generates a variable frequency from 12 Hz to about 60 Hz, with a center value (pot at 50K) of 20 Hz... perfect!
Furthermore, if you want to set up also the pulse duration (not only intervals between pulses) you can replace also the 10K resisitor with a 10K pot.

Step 3: The Full Schematic

Now I only need to add the power source for the laser diode, a switch and some capacitors as circuit protection.
I know that laser consumes 5 mW and it requires +5V DC, so as power source I used a 78L05 voltage regulator (which provides 5V at 100 mA max). The NE555 controls the laser through the PNP transistor (you can use 2N3906, PN2907, BC556, BC557, BC559, 2N2907...), which also is needed to reverse the output signal, so that the short pulse of the wavelength stays up.

Step 4: The Pcb

For now I decided to build only a prototype, but I also created a fast pcb if you wish to etch your own circuit. I used DipTrace which is a very simple software. It also develops a bill of materials, from which you can see the reference names and values for each component. C1 e C5 are electrolytic capacitors, the other three (smaller values) are ceramics with no polarity.

In the attached pdf you will find a board schematic ready for toner transfer method (top view). Look at my other instructables if you wish to learn how to etch your own pcb.

Step 5: The Prototype

Building a prototype was in this case essential, because I wanted to experiment different frequencies and take some test picture.
So I inserted all the components on a little breadboard and I connected a battery pack, composed by 4 rechargeable 1.2V AA batteries. Actually this could be a bit weak, because the resulting 4.8V is less than 6V required, anyway it works well. I still have to test it with 4 alkaline 1.5V batteries.

Step 6: Test Pictures

Finally I could take some test photos. To obtain the best result turn off any other light source so that it's almost completely dark, then set your camera to 800 ISO and full aperture width, choose the best shutter time depending on what you want to "paint" and... that's it!
As you can see the only limit now is your imagination ;-) I still have to try to shoot some portraits.

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28 Discussions

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vanhee_sander

8 months ago

Nice instructable and excellent pictures! You could also mount your laser to servo motors or stepper motors to precisely control movement in the x, y or z axis so your patterns are spaced evenly. Thanks for sharing!

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MerlinW1

3 years ago on Introduction

Thanks for this instruction! That is a great idea for photography. My dad and I are not very experienced in doing stuff like that, but... we made it! And it works!

For a more mystical effect, we tried to work with fog. But the laser seems to be too weak for that.

Can you tell us, how the circuit would look like with a more powerful laser? What intensity would you recommend? Please tell us in an easy way, we are no engineers. :D

Thank you!

1 reply
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andrea biffiMerlinW1

Reply 3 years ago

I'm very happy it works!
great idea using fog! yes probably a more powerful laser will work better, but it's more dangerous. anyway you can look for some green laser tutorial on instructables and adapt the circuit to it if voltage is different. good luck!

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tholopotami

4 years ago on Introduction

Really nice work! One simple thing I did not understand: In the pictures presented did you scan the laser by hand while taking the shot?

1 reply

yup, I moved the laser by hand in all these pictures. I also tried to hang it up to the ceiling fan and make it swinging, but those photos were not so nice.

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ASCAS

4 years ago on Introduction

Great idea on using DipTrace! I did not know of its existence. For some reason I don't like using Eagle, so I was stuck with Fritzing so I gave DipTrace a try and I love it! :D

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andrea biffiASCAS

Reply 4 years ago on Introduction

I also used Fritzing after Eagle, as you did, but Fritzing is not very precise if you want to make thin and dense traces... Diptrace is much more powerful, and it's free too (up to maybe 300 pins)

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ASCASandrea biffi

Reply 4 years ago on Introduction

I agree, Fritzing lacks the vector feature, the jagged edges seem to ruin thin lines.

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andrea biffiASCAS

Reply 4 years ago on Introduction

yes, I love it too, we have to thank Dave of eevblog, I saw his video about it and I tried Diptrace after being stuck with Eagle :-)

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andrea biffialcurb

Reply 4 years ago on Introduction

yes, I thought about that... probably making two passes from two different points, one with vertical lines, and the other with horizontal lines, you can make a software that separates the views and creates a 3D model...