I'm a student, very new to this, and need help. Want to build my first scanner.

[echelon]

Hello everyone, I'm very new here and to lasing in general. I am in need of a
massive amount of help / advice concerning a summer project I want to pursue.

I'm a computer science and chemistry student at a small undergraduate university
in Georgia. I'm very near to graduation, but I'm going to take the summer off
to cope with some sad personal "things". One of the projects I am very eager
to work on is building my own xy-scanner laser system. I don't know very much
at all about this field, but I'm determined to have something built and working
by summer's end.

My finals will wrap up in two weeks, and just as soon as they're done I'd like
to have some equipment already ordered and awaiting me.

I don't think anyone on my campus knows about laser scanners, but that said
there is an incredible amount of other expertise available at my disposal.
My Physical Chemistry professor specializes in laser systems and has promised
to help me on a number of issues. We also have a large engineering program and
plenty of equipment with which to build a custom housing for the laser. I can
get hands-on EE help, mechanical help, and so forth.


What I want to build
--------------------

I want to build a laser scanner system for use mostly outdoors. There
may be an occasional indoor use or two, but I mostly need to scale the
image to large dimensions as I'll be projecting onto the
buildings around campus, many of them quite large and quite tall.
(Nothing of the skyscraper variety, though having the capability to
project onto such a surface would be pretty nifty.)
I'm not sure what resolution requirements I'll have (bigger is better),
but scaling the scene up onto these buildings is what's most important. I'll
also need to be able to scale up and down depending on which building I'm
projecting onto. (I assume this has something to do with the galvo angles
being adjusted?)

I've been inspired by (and am in awe of) videos like these:

* [1] http://www.youtube.com/watch?v=EFWcAkxzkv4 (Laser graffiti 1)
* [2] http://www.youtube.com/watch?v=1M19vo0EYfI (Laser graffiti 2)

I'm not interested in simple "graffiti". I want to write applications
such as simple videogames controlled Kinect, Wiimote, or by another laser
(that I can chroma key detect with OpenCV and a webcam).

A Mario or Tetris clone would be easy to write.
I will definitely be doing 3D molecular visualizations because I simply
love cheminformatics. I could also use the system to run slideshow
presentations (indoors) since I give talks frequently.
It might also be fun in the long term to write an algorithm to
'vectorize' a movie like The Matrix, sync the video with the audio track,
and play it over the campus green. I'm not sure how feasible that is, but hey...
I just want to experiment with as much as I can.

Additional interesting demos:

* [3] http://www.youtube.com/watch?v=k6gismmL9yU (Kinect edge detect)
* [4] http://www.youtube.com/watch?v=h_Yu7bZiOig (Kinect control animation)

Video [3] for instance looks like it's just Canny or Sobel edge detect in
OpenCV. You don't even need a Kinect for that.

I expect that I'll be writing a lot of software this summer. Software to
communicate with and control the hardware, software to optimally control the
galvo positioning to achieve highest speed, a higher abstraction layer to
convert vector primitives into these hardware instructions, and then the
software applications themselves. For the most part, I don't mind low-level
programming and would rather not have to pay for any commercial software if
it's feasible, but if there is a chance that my programming could in any way
damage the equipment I may go with a pre-existing commercial solution if no
open source alternative exists.

(Any software I write will be hosted on github and available for all of you to
use as you see fit.)


Questions on Hardware, Theory, Practice, etc.
----------------------------------------------

1) Vector/Raster.
Galvos typically draw vector rather than raster images, correct? (I assume the
column-by-column, row-by-row demands of raster images are far too slow to reach
a framerate humans can percieve as video.) But are vector images still drawn
in row/column order, or is the image composed as the shortest distance "as the
crow flies" or by some kind of similar heuristic? I imagine such shortcuts
could vastly improve the framerate unless the scene itself is just too complex.
If there's any literature/theory out there, perhaps I can experiment with
writing different positioning algorithms depending on the application and
scene complexity--I think that will be really fun.

2) KPPS.
How expensive ($$) are they, and how high does it need to be to look good
on video without jitter? (Many of the videos above had a lot of jitter on
camera.) Does it scale inversely proportional to scene complexity? I want to
maximize KPPS (I think) and attain a very crisp yet complex image, but
minimizing cost is also really important to me.

3) Laser type, color, etc.
What colors project with the brightest intensity and can reach the farthest? If
I want to project onto the side of my campus dorms, or even a tall building,
what are the best choices? The standard green 532 nm laser seems to be well
known for distance and brilliance--is this the gold standard? How expensive are
others? If I order just the diode, how hard is it to build the housing?

4) Multicolor.
Can you mount different color lasers into the same galvo setup? That is, can
I use a single xy-galvo to display a multicolor scene by simply controlling
the software? If so, how much does that slow down the KPPS? (Linearly? Or not
at all?) Is it "better" to have only one color laser per xy-galvo? Or can I hack
multicolor?

5) Hardware setup.
Can you concisely describe the primary components of a typical scanner setup?
Lasers, xy-galvos, ILDA?, ... (there are lots of other components too?) What
about typical minimal costs for these components? Any open source software I
might be able to use? (Can you guys describe ILDA in general or point me to
something to read?)

6) Expected life of hardware.
How long do galvos last before burning out? How about lasers? Do different
types of lasers/galvos have longer life expectancies?

7) Clouds.
Are there any laser scanners that can project onto low stratus clouds? Is
this safe/legal to do given aircraft, etc? I know lasers are frequently used for
astronomical observations, but I certainly don't want to harm any pilots. If
these are legal, how much power would such a system require, and how expensive
would it be? It'd be pretty badass to play tetris on the clouds.

Conclusion
----------

This project _has_ to be done on the cheap. I'm considering dipping into my
scholarship and financial aid money to develop this system instead of eating
actual food. If I do a good job, I'm fairly certain that I'll make all that
money back from donations / additional scholarships. You see, my school
never sees students pull off stuff like this, and I'm pretty sure it will
resonate. (That's not why I'm doing this, but I do think my investment has a
high probability of being returned.)

That said, I need to minimize risk; I only feel safe using $2-3 k. That's the
budget, and I know it's probably unreasonably low. But I have to make it work
some how. Even if I have to cut some corners.

Everything I don't buy will have to be built on-site from materials
available around the campus. I expect that the galvos will eat the large
majority of the costs, and I think that's where I want to sink the money
anyway since I want a large, crisp, high KPPS image.

Also, if I impress the school with this, I might be able to get them to fund
future, larger-scale lasing endevors.

I'll keep checking back here, but I also intend to hang out in your IRC channel
as well. If you can walk me through the theory, a potential build that matches
my budget, and what I can expect, I would be extremely grateful.

Many, many thanks in advance!

(Sorry about the line wrapping at ~80 chars, I wrote this in vim before pasting here.)

[no-esc]

First thing is to read up on the rules and regulations regarding laser shows and ensure you comply with local and federal safety laws.


.......Now that's been said welcome to PL you seem to have been infected with the LASER bug. There no known cure. I look forward to your progress. At work ATM or I would give you some links to read. I am sure one the gurus on here will chime in very soon.

[JohnYayas]

Some answers...

1) Vector images are drawn by connecting the dots, the same as in a childrens puzzle book. The order of the dots makes a big difference in how fast the image can be drawn and thus the quality. Laser display is all about point optimization. Not only do they need to be in the correct order for the shortest path but extra points need to be added to prevent rounding off corners and that sort of thing. With experimentation, it is possible to determine what works and what doesn't.

2) You can get a decent 30K scanner for around $300. Maybe a little more or less depending on the source. These will do what you want.

3) Green is definitely the brightest and will give the most bang for the buck. 1W of 445nm is very cheap, though.

4) Multiple lasers are combined optically into a single beam before reaching the galvos. The software turns the lasers on and off to mix and create different colors. It has no effect on scan speed.

5) Scanner components are laser modules, mounts, dichro mirrors for combining colors, galvo set (consists of galvo motors, mounting block, and their amplifiers), power supplies. A single color laser just needs a laser module and a galvo set. Outside of the scanner is typically a DAC and they are typically a USB->ILDA device. Inside the host computer is software to control the DAC. ILDA is an organization that published some standards, among other things. One standards defines the pins on a 25 pin (DB25) cable. Google ILDA connector. Another is the ILDA file format. It's pretty well documented but there are variations from software company to software company so if you implement per standard you won't be able to load all that you come across. There is also an ILDA test frame that is used to tune scanners and measure scanner performance. All of these can be learned about with the Google.

6) Cheaps galvos will fail earlier than expensive ones. The $250 30K set I have has been abused and still works perfectly after several years. Others have bought more expensive units and have died without too much use. The really expensive ones will last the longest I guess but they are out of your price range.

7) Yes, lasers can project on clouds but don't even think about it because you can get in big trouble. Of course, at 3am when the planes have stopped flying and no one is looking... well.......

[dsli_jon]

Hey echelon -

Welcome to PL.. I was gonna try and help with some of the answers, earlier, but I just haven't the time.. *However* - what I'd like to suggest, is - #1 - TAKE THE TIME TO READ ALL OF THIS: http://www.photonlexicon.com/wiki/in...fety_Overviews -

..Specifically, this 'Overview PDF' - not so-much for the 'Regs' of-it (..since clearly, you're not doing 'commercial shows'..), but for the 'whys and wherefores' behind them... http://www.fda.gov/downloads/Medical.../UCM119257.pdf

#2 - I'd really suggest you 'rethink' your whole plan to 'mostly do outdoor demos' - UNTIL - a) you've gotten very-familiar with the FAA's Regs, for *any* outdoor display-use of lasers.. See here: http://www.photonlexicon.com/wiki/index.php?title=FAA ..Cause, they don't care if you're a 'student' or an 'innocent stargazer' - or a 'seasoned' laser-sho co - you get lasers into airspace, without permission, they will not-hesitate to drop an FBI-dime on your * ..and that's not something you wanna 'mix' with a university-career path..

b) Until you've mastered learning how to *properly* mask / attenuate, etc, your projector set-up, so there is little to zero-chance, you will 'accidentally' have a stray-beam(s) go off into airspace.. Sorry, but..

Of course, at 3am when the planes have stopped flying and no one is looking... well.......

..is actually a joke.. Gary has a great-sense of 'dry-humor' and knows that, especially in GA, with ATL being the busiest airport in the world, you cannot *guarantee* that there will absolutely-not be some flight-path / routing, somewhere - even well-beyond where you can visibly-see, but where even a 100mW Greenie *can* 'reach' - that might-possibly be affected, *if* you should have a 'slip-up', during your set-up / demo, etc..

'Cloud-projection' - when it even can be done - typically takes a HUGE amount of laser-power, and - the *express-permission* of the FAA, under very-controlled circumstances... ..Unless you're, like, in the Amazon, then, yeah - what Gary-said..

..Once you've gained a good-deal of experience, with lasers / projectors, and - operating safely - even at lower-powers - remember, most 'pointer incidents' are not with '1 Watt monster-pointers' - most are with, maybe 10mw - 50mW, maybe a little more... But the point is - learn / master-safety / know the Regs / gain experience indoors, *first*, then, take the step to doing outdoors-demos, etc..

Tell ya what - since you're looking to learn this all from the 'ground-up' - don't start with 'as many Watts as your dollars will buy you from China' For only the cost of a flat-rate shipping box, I'll offer to send you, a 10mW 'HeNe' / PS, all ready to 'plug and play' - with instructions for safe operation / do's / don'ts, etc, for Free (other than flat-rate shipping..), so you can focus on the other aspects of 'learning' this craft.. Sound good?

Lemme know, and.. Please, READ UP!
cheers..
j

[mixedgas]

Take him up on the HENE, it is THE most useful tool a beginning engineer can get his/her hands on after a milling machine and a decent oscilloscope.

Steve

[laserist]

A little unsolicited advice - Jon (aka dsli_jon) is someone who can keep you from stepping on your - ah - hose...

Being able to say Jon gave you your first laser is a resume item...

Brian

[colouredmirrorball]

Hi,

That's a great offer you got there! I only wonder how it is blanked, does it work with an Acoustic OptoModulator? Or is it not blanked at all? Even if it isn't, it's a great way of concentrating on software and scanning first.

Green is definately the way to go if you are into large scale projecting, but blue tends to be cheaper, especially if you build a module yourself. A 1 W 445 nm blue diode will cost you about $50 (unless you find a cheaper source, what's the price of these actually?) and depending on how good you want to engineer, between $100 and 500 for the housing and driver. The setup I use is a simple Aixiz diode holder with lens, in a mount hooked up to a Flexmod driver. It's dirt cheap, but the beam quality is horrible (which you do not want if you are working with graphics especially at larger distances as the beam tends to smear out and overlap) and I don't run it at full power because of the heat. When blanked (modulated) it stays pretty cold, but when I run it continuously it gets pretty hot even when attached to the large aluminium base plate. It's something you could consider, but when you are serious with projecting, you need some more corrective optics (look up anamorphic prism pairs), a good way to cool the diodes (usually with a Thermo Electric Cooling element) and maybe a way to combine multiple diodes (with a Polarizing BeamSplitter cube used in the opposite way, or 'knife edging'). We have a whole 445 nm section on this forum, on which you will find all ways to do this.

For scanners, I advice the better Chinese ones. I have a DragonTiger-30 scan set and I'm very pleased with them (but I suggest you go with the DT-40's at once, the price difference is not that much and they're 10k faster, but if you want to cut costs the DT-30's are fine as well of course). I can play simple games and logos on them, without a horrible lot of flicker. How much flicker you have depends of course on how fast your scanners are, and how many points there are in your frame, but also on the distance between those points and the size of your image. If you are projecting on a building far away you can shrink the image to reduce flicker. Number of points and distance is a software optimisation thing. With a reasonable scan angle and sufficient optimisation you can get away with frames consisting of 1000 points max without the flicker getting too disturbing (but with 1000 points the flicker will get noticeable!). At 500 points I can start to see flicker on my scanners, but that's just a rough estimate as I must admit I have never really did a flicker vs point count test, but it won't be far off. 500 points is a pretty complex image already.

Considering you can help yourself with power supplies and the case, the last thing you'll need is a DAC, the board that converts the digital signal from the computer (mostly USB) to the analog ILDA signals. You could go cheap again and just use a sound card. They work great as well, and some members on here can help you with converting a sound card. There are better options, however, that are much more stable and reliable. Your other options are a Riya DAC, an Easylase or an Etherdream.
A Riya is cheap and from what I've heard of it, it does its job pretty well. I don't know how easy it is to make programs that work with it, but I think it is possible.
An Easylase is pretty good but rather expensive (about $300 for a new one) but if you're lucky you can find one second hand for a good price. I have one and I can't complain about it, so far I've never had any problem with it. It also has some other I/O options such as DMX. People have also written some nice applications for it (such as the ZoofGames) and it should be fairly easy for you to write programs for it (also I would love to see some new programs to play with ).
The Etherdream is a pretty new DAC, and might be your best option. It's as expensive as an Easylase. The developer of this DAC is j4cbo on this board, who also is frequently on the IRC, so if you have a problem you can be helped immediately. As the name suggests it works over ethernet so you are not limited to the length of an USB cable, or USB drivers. The good thing is that it's open source so writing programs for it should be easy.

Now you need software. There are some free programs on the PL FTP server (check the stickied thread in the Administrative news subforum to get guest login info) that can produce an ILDA file and send it to a DAC, but they have a rather limited functionability.
One program I recommend is ILD SÔS from PL user drlava. It can convert vector art images such as svg and dxf to ilda, and optimise ilda files as well. It's an useful tool for converting logos if you can find a vector file of them.
Another program (partially) written by him is LSX. It's a laser show program and pretty good. You can do some neat stuff with it, especially when you're good at math. If you buy it, you get ILD SÔS with it as well. It's based on a timeline, even the live function. That's the program I use and it is great, though maybe a bit expensive.
You might as well encounter Spaghetti, written by JonnYayas who commented earlier, but I think you won't have much use with it, as it is mainly a program to create a laser show synchronised to music, and not much more than that (but he's planning on expanding its features).

Of course you could write your own software, I'm sure drlava, j4cbo and JohnYayas can help you with that.

Also stay away from Pangolin. Their FB3 is not what you want as it does not have an SDK and it only comes standard with QuickShow, which would be a pretty useless program for your application. Maybe you could do something with their QM2k, but that's a very expensive DAC ($2000 iirc!) (and rumour has it it's actually not better than the etherdream)

[echelon]

First of all, thank you all for your wonderful responses and support. You guys
seem like a great community, and hopefully as I develop my experience in this
area I can one day become as helpful a contributor. This is really
great--thank you so much!

I'm sorry I didn't respond earlier, but finals are going to keep me very busy
for the next two weeks. I'll do as much reading and investigation as possible
though, because I'm very eager to start just as soon as finals have ended.

I understand that safety is a huge issue with lasers, and I'll make certain
to read everything you guys have posted in regards to both human safety and FAA
compliance. I do eventually want to build an outdoor system, but that doesn't
have to be my first build. I can work from indoors first and perhaps by
summer's end I'll have more experience. (I'll let you guys know how I'm
progressing--you can advise me to stay indoors if you think I'm not yet
ready). If and when I do reach that point, maybe I can develop a second scanner
setup or scale up the one I started with to working outside. Or, if I develop it
initially for such a purpose, I promise not to use it outdoors until I'm ready.
I'll just see what works best, budget-wise.

Is there any good eyewear that filters out all of the relevant wavelengths used
in lasing? I'll have to buy a few sets for myself and my colleagues. If it's
expensive, I'll try to buy specific for the wavelength I know I'll be working
with.

I'm going to scratch the "clouds" idea completely... it sounds way too
complicated to be safe and compliant, and as a beginner I know I can't do this.
(Thanks Jon! You certainly convinced me that this is extremely unwise.)

JohnYayas:

30K galvos on the order of ~$300 sounds like a good initial cost; I don't want
to ruin a good pair of them before I have had experience (unless they come
under warranty). How much do you think the entire build would cost outside of
these galvos? (And is 30K fast enough to draw a fairly complex scene? I'll
read up on KPPS just as soon as I get the chance.)

What three lasers (perhaps R, G, B?) would be best to combine to produce
a wide range of output colors in a cost-effective manner? When I do eventually
work outdoors, how powerful will they need to be to shine on a building and
still produce vibrant color? I hesitate to use wattages that are too powerful
for a beginner though. I don't trust myself to be 100% safe until after I've had
experience; I do not want any accidents. I can always upgrade the lasers later.

Jon:

Again, thanks for explaining all the safety issues. I'm going to take things
slowly, work only indoors for a long while, and definitely stick to low-wattage
lasers. After I've learned the ropes, worked with the hardware awhile, and
written a lot of code, I'll let you guys be the judge of when it's time to
scale up and move outdoors.

Thank you so much for offering me a HeNe laser! I'll definitely take you up on
it! (I'll send you a PM shortly.)

colouredmirrorball:

I get the sense that heat dissipation is going to be a big problem with some of
these lasers. If I stick with low-power lasers, will this be a non-issue?
When I do scale things up, can I develop a large housing to keep the optics as
far apart as possible to minimize their contributions to total heat? Aside from
a heat sink, do you typically employ fans?

My knowledge of electrical and mechanical engineering is pretty poor, but do you
think a beginner such as myself could build a laser from the diode, driver,
etc. directly without too much trouble? I've only done extremely basic
soldering work, but as I mentioned before I should be able to get some
assistance from the campus EE department. How hard is it realistically? Would I
be better off getting something already built? (Granted, I _do_ want to learn how
to do this. I just don't want to destroy the equipment on my first go.)

The Etherdream DAC sounds like a winner. I like open source, and the network
option sounds awesome; plus, I won't be tied to a computer a few feet away.

Misc. questions:

Can the 30K galvos that JohnYayas mentioned reach 1000 points max with minimal
flicker, or do I need higher KPPS? I really want to minimize flicker, maximize
points, and maximize drawing distance, so I'll invest more in the galvos if it helps
and still falls within my budget. I don't want to have to scale down the
image--if anything, I want it to scale up. I may be forced to reduce draw points if
it's absolutely necessary.

Could I get a second laser/xy-galvo/DAC to work synchronously with another set
in order to effectively double the number of points or the scene complexity?
With a clever algorithm, it may do more than double scene complexity since the
vector draw points could be clustered to each galvo, giving them both smaller,
optimal drawing paths. Would aligning and rectifying two separate galvos be
hard? (This setup might be way too expensive to even try. I need to get my feet
wet with the basics anyway.)

How inefficient is it do draw "solid" figures instead of outlines? I've seen
several videos where lasers are used to "paint" solid surfaces. Perhaps I can
cheat a little bit and draw alternating scanlines that give this illusion.

Are there algorithmic techniques for "fixing" the "frames" per second? It would
be nice to have it uniform and not jump in and out of choppiness. I'd love to
have a hard limit on each frame's complexity.

Can you electronically apply cw/ccw polarizations to the light and use 3D
glasses to filter the opposite polarity? If so, could you develop 3D stereo
animations (with glasses / polarization filters), or will reflecting off
of a surface change the polarity?

Thanks again, everyone! I have a few exams over the next two days, so I'll be
away, but I'll be back again very shortly and try to run a few example builds
past you guys for your stamp of approval. If you have any specific hardware
recommendations, please let me know. (The Etherdream DAC already sounds
like a must buy.)

Thanks so much!

[JohnYayas]

I'll answer a few questions:
The total build cost depends on if you build it yourself or have someone else build it. I have an RGB scanner and build most of it including the optics mounds. It is a 30K 50mw-G, 200mw-E, 600mw-B projector and I probably have about $750 tied up in it. That's a rough guess and it could actually be +- a couple hundred dollars. The galvos cost $250, dichros about $50, about $100 worth of aluminum, around $250 in lasers (although I could do it cheaper these days), another $40 for a power supply and then throw in another $75 for odds and ends and that covers most of the cost. So, yea around $750.

Even my puny projector will show a visible image 50yds away at night on the neighbors house. But, it isn't bright. Just visible.

Yes, 30K will do pretty complex shapes. It's the standard projection speed so most images are made for 30K or less. Faster is better because, if anything, you will get a larger angle.

1000 points is ok. I have some frames that are 1500pps and they display nicely but they do flicker some.

I have answers but not time for your other questions. If you'd like to start a discussion about some more of these things in detail send me a PM since I am usually too distracted to pay close detail to forum threads.

I'd be leary of the Etherdream DAC. I'm sure it works well but it's basically a few people on this forum who decided to design a DAC. From what I gather it costs as much or more than some commercially available DACs that also have APIs so ask the right questions before you buy.

[dsli_jon]

hey eche -

I understand that safety is a huge issue with lasers ...I do eventually want to build an outdoor system, but that doesn't
have to be my first build.

It's not to make a 'mountain out of mole-hill' nor be a 'Regs-nazi', either - as many people point out, we live and work around 'dangerous' things every single day - my fav example to use is, driving - really, what 'separates you' from death / serious injury, when driving on a two-lane road w/ no 'median' or divider - 2 painted yellow lines??!! So, yes, you need to put it all 'in perspective'..

Nevertheless, some simple precautions / education / best-practices, and, a reasonable-level of 'safety-hardware / features' - ie: seat belts in our cars - certainly prove themselves a 'good idea', regardless of the slight 'restrictions on total freedom', when you do, for-example, get in that 'head-on crash'.. similarly, the laser-Regs are 'restrictive' - and yes - NEED TO BE UPDATED to todays' standards / systems, etc, but once you get to comprehend the 'spirit of the law', as well-as 'the letter', you'll see where you can be a bit more 'relaxed' about certain things - but, also, where you need to be as-strict - sometimes, even stricter - than the 'Regs' specify.

I'm going to scratch the "clouds" idea completely... it sounds way too complicated to be safe and compliant, and as a beginner I know I can't do this.

Again - not trying to 'squash your spirit' it's just like - imagine you had a kid, and, the day he turns 16 / gets his drivers' permit, he says, 'ok, Dad, got my permission.. now, gimme the keys to the Hemi..' I mean, maybe the kid will turn out to be a racing-champ, but.. 'small steps' will ensure he makes it there...

Again, thanks for explaining all the safety issues. I'm going to take things slowly, work only indoors for a long while, and definitely stick to low-wattage lasers. After I've learned the ropes ...I'll let you guys be the judge of when it's time to scale up and move outdoors.

If you can make it to the 'South East Laser Enthusiasts Meeting' - aka "SELEM", in August, in NC, you'll a) have a BLAST b) get to meet a great-deal of laser 'DIYers', at all-levels of experience - from 'beginners', to a few industry-experts c) ask as many questions as you like / get 'hands-on' demos, etc, and d) come to think we're all a bunch of 'hypocrites' - jk, it's just that, you'll both see the practical-application of 'the Regs' / safety in-action, and, the 'balance' of people working around multi-watt rigs, and immersing-themselves in a laseriffic good-time.. Basically, it's a great-way to 'get up to speed', meet a lot of great peeps / make new friends, etc, and have a Gr8 time..

..although, since it's in mid-August (..watch PL for 'announcement threads' about SELEM 2012..) that's almost when you are looking to be 'done' with your project, so.. Perhaps you can look to 'meet-up' with some of the regional 'SELEMers', sooner... most all of us / them, are quite-ready to help 'beginners', as time / work permits, etc...

..I'll definitely take you up on it! (I'll send you a PM shortly.)

Cool. ttys..
j