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.
<p>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! </p><p>For a more mystical effect, we tried to work with fog. But the laser seems to be too weak for that. </p><p>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</p><p>Thank you!</p>
I'm very happy it works! <br>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!
<p>Really cool idea and great 'ible. In fact it's the first instructable that I've ever completed. I threw together this prototype to try it out but I have access to a circuit board cnc so I'm planning on making it a permanent device and modifying the original circuit a bit. I'm also using a 5mW laser which is pretty dim but I know from experience that lasers up to 100mW are relatively safe as long as the beam is dispersed and not a point, so I might increase the power in the future. BTW is there any chance of getting the DipTrace project files for the PCB? It would make my job a whole lot easier since I can't utilise the toner transfer picture.</p>
<p>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?</p>
<p>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.</p>
<p>do you have a link where the laser will move like in the club</p>
<p>pictures are made with an exposure time of several seconds, so a video would not work...</p>
<p>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</p>
<p>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)</p>
<p>I agree, Fritzing lacks the vector feature, the jagged edges seem to ruin thin lines. </p>
<p>yes, I love it too, we have to thank Dave of <a href="http://www.eevblog.com/" rel="nofollow">eevblog</a>, I saw his video about it and I tried Diptrace after being stuck with Eagle :-)</p>
<p>Someone has to use this to paint on a wall with photo-sensitive dye (like inkodye)!</p>
<p>great idea!</p>
<p>Wow, i love it o.O I want it!</p>
<p>Hey Jan your electronic skills are deeper than mine! Just make it! ;-)</p>
<p>Haha, thank you :D</p>
<p>cualquier transistor pnp funciona no colocaste el numero de dicho transistor</p>
<p>you can use 2N3906, PN2907, BC556, BC557, BC559, 2N2907...</p>
<p>Very nice idea. It definitely has other uses such as a 3D scanner.</p>
<p>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...</p>
<p>Wow, this is a very neat idea Andrea! Well documented, thank you for sharing! :D</p>
<p>Thanks! a more powerful laser to photograph buildings would be great, unfortunately danger that people look into it is too big..</p>
<p>use 5 units, the 555 can be the master clock, and 5 -25 led lasers be synchronized slaves. This also allows for several different colors.</p><p>This was very nice, took me back to a time when I had hair on my head and was much much thinner! I built a dance floor with 3,000 lights all hail the Mighty Disco! </p>
<p>Another source for a line would be to get a laser level from Harbor Freight...</p><p><a href="http://www.harborfreight.com/hand-tools/levels/16-laser-level-with-swivel-head-69259.html" rel="nofollow">http://www.harborfreight.com/hand-tools/levels/16-laser-level-with-swivel-head-69259.html</a></p><p>They used to have 'em without the tripods for \$12... -- the &quot;line function&quot; is a lens that snaps over the laser.</p>
<p>that's right, but it's much more expensive, for 12\$ you can have 5 of them (line lasers) on ebay...</p>
If you have a glass rod across a laser pointer which gives a dot to turn it into a line. You could maybe try it with a stem of a wine glass if you have that handy
<p>This is so cool!</p>
<p>:)</p>