Make a Laser Matrix Projector for the iPhone
The Concept
The idea is to add some kind of projector capability to a cell phone (e.g. iPhone) that isn’t too complex or expensive. Instead of using an expensive mini projector, I decided to use lasers instead to any bitmap font using a matrix of laser points, which is controlled by iPhone.
The Hardware
The hardware contains 3 basic parts:
- 5×7 laser matrix
- 5 8-bit D-type latches (SN74LVTH573PW) to control the total 35 laser pointers
- Microcontroller (PIC16F722) to control the decoder and manage the serial communication with iPhone – grab the code.
The laser modules can emit 650nm red laser light, with power consumption of 2~5 mW. Since the laser light is very narrow, any tiny movement is misalignment alters the matrix. So the tricky part is how to position the total 35 laser lights in parallel. I drilled the holes in a plain PCB board, and placed our lasers into the holes.
The Software
The micro-controller software is fairly strait forward, it just waiting for command sent by iPhone via the serial port, and execute the command by controlling the 5 latches. It’s that simple and could be done with the Arduino if you wanted.
Here’s what the application looks like on the iPhone. You can type any message to be displayed with the lasers. Amazing displays can be made using lasers. With laser projectors the skies aren’t the limits.
The iPhone side software is a bit more complex. Apple just added the serial port support in its iPhone SDK 3.0 beta. However, I’m still using the old iPhone 2.2 firmware and haven’t bothered to upgrade yet. So I used an unorthodox way to implement the serial port communication. Basically, I grabbed the IOKit framework from iPhone and load it into Xcode, so that the program no is able to access the /dev/tty.iap. Looking back on it, it’s probably better to use the built in 3.0 SDK serial.
After establishing serial communication, the rest is fairly easy, just send out the commands to eLaser hardware and illuminate the laser lights.
The End Result:
If you wanted, you could put more powerful lasers in your matrix and project on the sides of buildings from a few hundred yards away.
Video Demo:
(I had some issues getting the keyboard to come up 
This post was submitted by a Hack N Mod fan, just like yourself. If you’d like to earn money from your projects, feel free to contact us.
May 19th, 2009
and for extra hackage, you could use surplus PS3 diodes. Obviously for sensible cost you’d want to use a 4*4 or a 4*3 matrix, but it would project multiple colours and shades.
Driving them isn’t that hard, you just use a small LM317T based driver and have the PIC etc “step” the current to one of four levels.
-A
May 19th, 2009
I would consider this a relatively poor design since 35 lasers has far surpassed the point where a basic scanner would have been cheaper, smaller, and far higher resolution.
As well as that, spending 6$*35 on lasers is borderline insane considering you can get the same model for around two dollars and these (which are identically speced) for 0.98$ (10+) including shipping.
Congrats on wasting your money on a wasteful design.
May 19th, 2009
He didn’t pay $6 per laser, he got them for 40 cents a piece on ebay.
May 20th, 2009
Oh please, don’t use that video service again : (
May 20th, 2009
Hey, can you install it on http://interactiveiphone.com so I can use it?
I think it is a great project!
June 7th, 2009
Hi, I put the OIKit.framework from my iPhone into Xcode and I’m using some parts of the code from serial.c to access tty.iap
How did you actually manage to write to that port?
October 12th, 2009
can you help with the serial port Access using the NEW SDK ?
October 12th, 2009
Haven’t taken a look into it yet, but we’ll post our findings when we do.