Laser show for poor man

Step 1 Gathering stuff

Design is quite simple and employs regular parts and components but you are free to change/modify it in way you like.

At first prototype I used blank DVD as reflective material but later I discovered more practical way. Technology of making FS mirror is described in my article
DIY Front Surface Mirror

Originally I'm very lazy man so I've chosen programmed microcontroller PIC18F1220 (can be replaced with PIC18F1320) to handle routine job.

PIC implements 3 channels PWM generator.
Actually it's the same engine as one I used in my IKEA light project just code is adopted for PIC18.

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.
Device accepts 5V and 12V fan with maximum current 200mA . Voltage is selected by jumper.

Green laser pointer is rated at 3V so I've made LM317-based voltage regulator with adjustable output.

Cheap 5mW green laser module:
http://www.dealextreme.com/details.dx/sku.10094~r.32746761

What else will you need?
Dozen of resistors and capacitors, potentiometers, toggle switch, power jack, prototyping board, box of proper size and power supply unit.

Comments

[jmartis004]

How much would a kit be?
[e-mail]

[AP Digital light]

Email has been sent.

[jmartis004]

I dont think I got it. What is yours?

[AP Digital light]

I've sent you PM.

[vophamduy]

Hi there,
Can you provide me preprogrammed chips and kit.
Contact me with this email: [e-mail] :-)
Thank you.

[AP Digital light]

Email has been sent.

[kservais]

 could you please provide me a preprgrammed chip and kit aswell?
Contact me with this email: [e-mail]
Thank you

[AP Digital light]

email sent

[moire]

Hi There! I have built this project, and it is fantastic!!! Thank you, AP Digital for the great intructions!!! Unfortunately I couldn't get front surface mirror, so I cut out from hard disk with dremel. It is front mirroring, and perfectly smooth. Cannot make it perfect circle, but it doesn't matter... :) Works great! My problem is now that the LM317 is getting very hot and after a while the laser dimmes and finally out. After it is cooled down, it's working again, but when it is hot it is getting dimmed. First I used 12V adapter, and it was ok for about 30 seconds before the laser turned off. Then I changed it to a 6V adapter, to avoid heating 9 extra volts between 12 and 3 (which is the laser operational voltage). Now it is much better, but after 1-2 minutes, it slowly dimmes again and finally switches off even with heatsink on the transistor. Do you guys have any idea how to keep the laser power and/or transistor temperature low? I'd like to operate it longer. Thanks in advance! BR, Moire76

[AP Digital light]

LM317 can handle up to 125C before shut down due overheating. Try to monitor voltage on laser. Does laser dim when it's powered from batteries? I think it's laser's issue. I have few modules with similar symptoms. It's really bright at the beginning but after laser got warmed up, beam dims and stays at the same level no matter what's voltage is applied. Important note about heatsink. LM317 has output voltage on its metal tab, LM7805 has ground. Don't install LM317 and LM7805 on one common heatsink or you'll short them!

[moire]

Thanks for your answer! I may try to get another diode then. BTW I redesigned the PCB and replaced the LM317 with switching mode power supply. It is much more reliable and no heating problem! :) If you are interested I can send you details if I am ready with the project. Here is the schematics for the power supply of the laser diode, and parts diagram and the integrated with the original pcb design. I can send you SprintLayout file upon request. BR, Moire

[moire]

Thanks :)
Yes it needs a few more parts, but I had no other choice because I couldn't get over the over driving problem.
Just for those who is interested:
The red rect. is the output of the power supply, the yellow is the input.

The exact output voltage formula: U=1.25(1+R2/R3)
I used a 1KOhm resistor for R2 and a 1K potmeter for R3 so that I can finetune the output.

No need for heatsinks, stabilized output voltage.

Best whishes,
M.

[AP Digital light]

Great job!!! Thanks for sharing. ... Although you can use LM317 based switcher and save some parts. ;-)

[Wyle_E]

Your laser must draw more current than the original. That copper tab on the LM317 is intended to bolt to a heatsink. If you use an aluminum cabinet, you can use that, extending the three leads to the PCB. In a plastic case, a few square inches of sheet aluminum or copper (thicker is better) should do.

[xchrisx115]

where can you buy a microcontroller and what exactly is one?

[AP Digital light]

PIC18F1320 Available from DigiKey.com I can provide preprogrammed chip/kit upon request.

[xchrisx115]

And what are these.. i dont know what any of them are: Dozen of resistors and capacitors, potentiometers, toggle switch, power jack, prototyping board, box of proper size and power supply unit.

[AP Digital light]

See archive on step 2 for list of components but to assemble all stuff together you have to know electronic basics.

[qoen]

nice project dude! even that nice that i am fixxing it currently :) I just ordered the F1220 because the 1320 where sold out. I created a nice print, just like yours. just got 1 question; Is the 1220 pin-up the same as the 1320? so when I load the hex file, plug it on, it will work? greetings from Holland

[AP Digital light]

It's the same chip. Difference is only memory, 4K versus 8K. Make sure you load proper hex file. 1220 version is provided as separated file. See step 2. Rename it as *.hex after downloading.

[taggerung]

cool