Beginning laser projector build and first post, all advice appreciated

[tej2795]

Hello all!
My name is Tom and I'm an engineering student at Texas A&M University. Some background info: Lasers have interested me since the first time I saw one at the Fort Davis Observatory many years ago. The continuous green beam that appeared to extend on forever as it pointed to the stars was a surreal moment for me. About a year ago I purchased my first laser (50mw 532nm from China) and I was hooked. Somewhere in the mix of reading-about/studying lasers, I realized that the beam visualization is what really interested me. Once I learned about the numerous visual effects that could be utilized, I began planning my first build. I've got some programming experience so I bought an Arduino Uno starter kit and worked through the projects to get a feel for circuitry. I designed and re-designed my prototype system countless times on paper. The first designs were way to complex for my current knowledge so I had to simplify certain components. I am motivated to create a control board for different laser visualizations and my main focus on my first prototype is going to be the galvanometer for beam effects and not necessarily designs on a wall. I plan to control the effects manually as music is being played. In a later design I may try to make the effects "play" autonomously. I have dedicated a month this summer to focus solely on this project and am about to begin ordering parts.

I am about to purchase DT 30s for $380 from either lasershow parts or stanwax. I plan on combining rgb lasers with dichrotic mirrors and sending them into the galvo. I plan on using an external power supply to power the lasers and galvo, and I hope to be able to control the input voltage using an arduino. The control board is my main concern and focus. I want to be about to have preset buttons corresponding to specific frequencies that I want the galvo to "play". I might try and use a mini keyboard for this if I can map each key to a specific output voltage. I also want to have preset buttons for a sequence of frequencies that I wish to be played while blanking in between for added effect. Is there a preferred code for this type of functionality. Any advice will be greatly appreciated!

[Bradfo69]

Hi Tom,

You asked for advice. First the practical... Welcome to the slippery slope. Once you're hooked... you're hooked. There are cheaper interests, like women, boats, drugs and landing on Park Place when your opponent has a hotel. You have been warned.

You're in the right place and we love to see people building things so be sure to post pictures and ask questions. There are perhaps cheaper, easier ways than what you have planned but, there is an awful lot to be gained from the learning experience of building your own and perhaps a re-invention of the wheel with your control of the galvos. There are many, many solutions on how to do that, consisting of various software and hardware, since controlling effects manually as music is being played is exactly what many of us do. Some on a professional level and many as a hobby. I suspect however, that being an engineering student, starting off by designing and building your own solution is the preferred way for you to go though. I don't know much about Arduino but there are a number of people here that are that I'm sure will be willing to chime in.

There is a huge wealth of information on this forum and a number of build threads showing you what other people have done so, my suggestion is to search and read, search and read. The DT30's are fine and both Stanwax and Dave at Lasershow parts are reputable sources for them, as well as any of your other parts such as the dichros, mounts, electronics and the lasers themselves.

Be sure to have a look at the Pangolin web site and specifically Bill Benners projector wiring scheme as it may save you a lot of headache in making sure things are wired up correctly to give you smooth output and not suffer from strange ground loops and other jittery output.

Most of all... have fun with it!

[tej2795]

Thanks that's all great advice!
I just typed out a reply and ended up deleting the whole thing by accident so I'm going to try and keep this short and sweet.

I was very close to purchasing the DT30s however the price jumped $100 (not shipping, not tax) at the last payment step...seems kinda fishy. I'm waiting to hear back from them before I comment further on the issue.

I'm definitely going to continue to read more builds to get a better understanding of the various ways to solve the problem. The last thing I want to do is overcomplicate the problem, solve the wrong problem, or spend money that I don't have to. Perhaps you could shed some light on alternate approaches I could take. I'm taking this build one step at a time while trying to solve each problem in the simplest, yet most efficient manner. Throughout my reading there's one thing hat I'm still having trouble understanding and that's how exactly an IDLA galvo responds to an input signal. If an IDLA galvo has input pins for the X and Y (each 0-5V), does that mean that if I supply 5V to them then they will oscillate as fast as possible? How fast can I change this input voltage without hurting the galvo? I'm thinking I'm going to plot some data points in excel to find the relationship between input voltage and frequency. Then I can linearize it and some real magic can happen!

[Bradfo69]

Thanks that's all great advice!
I just typed out a reply and ended up deleting the whole thing by accident so I'm going to try and keep this short and sweet.

Been there... done that... got the T-shirt. I'm not a typist and so, when I've written a long post and lost it, generally just want to go cry. There is an auto save feature I found once but, I forget if it was for posting or for PM's.

I was very close to purchasing the DT30s however the price jumped $100 (not shipping, not tax) at the last payment step...seems kinda fishy. I'm waiting to hear back from them before I comment further on the issue.

Rob Stanley (Stanwax's) site says $367.70 (before shipping, using US funds). There is a riser block for $18 you may want to get as well. The block that the scanners go in is often too low to match up with some laser modules and the riser raises it up to a more standard laser module height. Dave at Lasershowparts has them listed at $345 US. He sells the riser block as well but I don't actually see it listed on the site. If the price changed in your shopping cart, I'd simply send them a PM and question it. Both are upstanding guys and there shouldn't be anything "fishy" going on.

Not that I want to take business away from either of these gentleman but, another set worth considering are the Phenix PT-40's from Lightspace in China. (Omar here on the forum) If I recall, they are either $220 or $270 and in my opinion hold up very well against the DT's. Especially if you're on a college budget and looking to save a little bit of money. You also shouldn't need the riser block.

I'm definitely going to continue to read more builds to get a better understanding of the various ways to solve the problem. The last thing I want to do is overcomplicate the problem, solve the wrong problem, or spend money that I don't have to. Perhaps you could shed some light on alternate approaches I could take. I'm taking this build one step at a time while trying to solve each problem in the simplest, yet most efficient manner. Throughout my reading there's one thing hat I'm still having trouble understanding and that's how exactly an IDLA galvo responds to an input signal. If an IDLA galvo has input pins for the X and Y (each 0-5V), does that mean that if I supply 5V to them then they will oscillate as fast as possible? How fast can I change this input voltage without hurting the galvo? I'm thinking I'm going to plot some data points in excel to find the relationship between input voltage and frequency. Then I can linearize it and some real magic can happen!

First and foremost, it's ILDA, not IDLA. It's short for "International Laser Display Association". Part of what they do has been the creation of "standards" for the laser show industry. Tuning, cabling, etc. The idea being that something created on one projector should look the same on another projector and, the pins on the wiring of them is the same as well.

Your galvo's are going to have a driver. That driver is really going to receive power in two ways, first is probably around 24v or so from a power supply to run them and then, lesser voltage from your control signal to make them move. Commonly, that "control" signal is coming from software which is then going to a DAC and then from the DAC to the projector. (There are all kinds of DAC's.) For example Pangolin has the Flashback 3 or FB3 and a more sophisticated one called a QM2000. People who use LSX software often use a DAC called an Etherdream, made by a member on the forum. There is also a company called Riya that makes a couple different DAC's. But the list doesn't stop there. A company called Showtacle has Moncha and Fiesta which are their two software and hardware platforms. Another company called Phoenix has software and a DAC. Medialas has software and their own DAC. The list goes on and on. Some people have even built their own DAC's using computer soundcards. I "think" this is perhaps what you're trying to do with the Arduino. Essentially make a DAC. So in a sense, that's what I mean by reinventing the wheel. You could spend $200 on an Etherdream and eliminate messing with the Arduino all together. BUT being an engineering student, you may prefer the idea of building something on your own. I get that.

So... You tell the software you want to draw a circle. The software talks to the DAC and the DAC (I believe) puts it in a language (0-5v) that the scanner drivers can understand and then, the drivers send it to the galvos and tells them to move in a particular direction a certain amount. I could be wrong but applying 5V to your galvo straight away means you're going to be placing another order with Stanwax or Lasershow parts pretty quickly to replace your dead galvo.

Now... speaking of software. As mentioned above, these various DAC's work with various software packages designed to allow you to create your vision for what you want the lasers to do. They range from free to a couple thousand dollars. They also have great varying degrees in what they do. Some are designed to just create frames. Some include the ability to put those frames together as a show. Some include the ability and are designed for playing along live with music in real time.

Laserboy made by a member here is free. It does a lot but, is not necessarily suited for "playing live". Next there are things like Spaghetti and ildaGen both created by members here that cost a little bit but have more functionality and allow you to start creating shows but, both still lack great functionality for playing "live". LSX is another very powerful software platform that is very good at creating shows but also is lacking in the playing live department. Then getting into something a little more expensive, Moncha from Showtacle and Quickshow from Pangolin are much better suited for playing live and have a lot more features for creating preprogrammed shows and have a lot of frames already built in. Both also have online repositories of shows other people have created for you to download for free and play.

Phoenix, Fiesta, LD2000 and Beyond are all even more sophisticated pieces of software - all with their own DAC's but also getting up to that $900-$5000 price level. And now, you're talking about what the pro's use.

HOWEVER.... remember what I said above. Women, boats, drugs.... If you're around for awhile you'll quickly discover you'll want one of these packages and wish you had just saved up and bought it in the first place. Best value for the dollar beginner package is going to be Pangolin's Quickshow with an FB3. If you hurry... you can also save some money by buying an FB3 here: http://www.photonlexicon.com/forums/...tarting-at-250 and the Quickshow software is actually free to download. If you ever decide this isn't for you, I'm willing to guarantee you'll get back what you paid by selling it.


For building the projector, here is a very, very good thread to try and follow. It's tiny and could be built for not a lot of money but, VERY well done. (I want one!!) http://www.photonlexicon.com/forums/...ode-rgb-built-)


(If I'm full of shit and have something slightly incorrect above - I'm fine with others correcting me. )

[tej2795]

Thank you for this.

This is exactly the information I have been looking for!

[hakzaw1]

.... I HAD A LOT OF WHAT I *THOUGHT* were money saving projects only to find it cheap and way quicker to use what most are using-[I] wasted time & $$ messing with stuff like steppers duh!

-- buying from USA right from the start is smarter- cheaper/quicker to ship and getting help later is not such an ordeal.. I suspect some DTs will be sold used soon because of the Pangolin scannersets.. but most amps & drivers will be kept..

hak

[Draco]

One thing i would like to add is the galvo drivers use a differential signal so it's not 0-5 it's more like -5 to 0 to +5 so a swing of 10 volts so don't forget a dual rail power supply if not included that is. and as stated don't feed them dc or do what i did, get a converter to make the audio into a differential and feed full range to the galvo amps, i did not lose the galvos but they sure did over heat...

I have been playing with Arduino myself but i realy need to learn the code and don't currently know of a good way to learn C for free.

[tej2795]

Thanks for the advice,
I may have very easily over-looked this. As far as power supplys go, do you think I should just pick up something from a local hardware store or are their better(cheaper or more specialized) options online?

As far as the Arduino goes, you probably are fully aware of this but encase not, their website is a great resource here and it's free!

And lastly, I don't have much experience with wiring lasers. I'm thinking I might be able to save alot of money buy building my own laser+driver. I found a good build here. I just really need to read up more on how lasers are wired up because I don't know how hard this would be to make compatible with FB3(I couldn't resist getting one Bradfo69 haha). I'm asking myself questions such as "do I need to buy an IDLA interface board to easily link everything together", "does a shutter work buy turning a laser on and off, or is it just a blanking mechanism". I might build my own shutter controlled by a push button.
Mabee I should just go big and buy a few DPSS lasers (if i can find decent price).Hah! I wish

Any clarification or helpful links would be greatly appreciated!

[Bradfo69]

I may have very easily over-looked this. As far as power supplys go, do you think I should just pick up something from a local hardware store or are their better(cheaper or more specialized) options online?

I think what you're going to want to focus on are probably not something you'll find at a hardware store. Or a computer store for that matter. (While computer power supplies "can" work, I've heard of a lot of failures.) Basically you're probably best going with a caged, switching power supply. Something from a company like Meanwell or Traco. There are also cheaper Asian supplies but, your best bet is really spending the relatively few extra dollars for something brand name. Here's the deal... you're dealing with sometimes very sensitive and temperamental electronics. You want to feed them a quality power source that keeps the risk of voltage spikes, noise, ground issues, errant bad soldering joints to a minimum. So what if you spend $35 on a good supply as opposed to a cheaper one for $20. In the long run, if it keeps you keep from frying a $200 diode, isn't it worth it? Something that looks similar to the enclosed supplies at the top of the page here: http://distributor.meanwellusa.com/w...iessearch.html

I'm thinking I might be able to save alot of money buy building my own laser+driver.

And time... and frustration.... You may do well at first to buy them as a set. When people here are getting into discussions on drivers, it's because they're getting right down to the diode level and making up their own heads with mounts, lenses, etc. and need something to drive them with. You can also buy the head and driver combination together - such as this listing: http://www.ebay.com/itm/445nm-2W-Blu...item20f4731d5f

With that, the wiring becomes much simpler. Red and black for power and then another probably thinner red and black for the signal from the computer/dac/ILDA cable.

I just really need to read up more on how lasers are wired up because I don't know how hard this would be to make compatible with FB3(I couldn't resist getting one Bradfo69 haha).

Good for you! While you are waiting for it to arrive. You can certainly go to Pangolin's web site and download Quickshow so you can begin to explore it. I highly suggest also going to Youtube and watching the Quickshow Tutorial videos done by Bill Benner.

Start with the quick intro video here: https://www.youtube.com/watch?v=AZzD...57BE052B6F4CD4 and work your way through. You will be amazed at all the things you're going to be able to do. I found it helpful to have Quickshow open on one computer and the tutorial video running on another so I could be clicking and following along. I've gone back to reference them from time to time too.

As I also said... if you decide this isn't for you, I'm willing to guarantee you'll be able to get back what you spent on the FB3.

I'm asking myself questions such as "do I need to buy an IDLA interface board to easily link everything together",

Take a look at the one word in the middle of that sentence.... "Easily" Yes, by all means an ILDA board easy wiring kit makes it SO much easier.

Something like Stanwax's for $8.00+ here: http://shop.stanwaxlaser.co.uk/gener...oard-365-p.asp or DZ's here: http://www.aldebaran-systems.com/BBv3.htm for $20 are both excellent. Is it worth $20 to not rip your hair out?

"does a shutter work buy turning a laser on and off, or is it just a blanking mechanism". I might build my own shutter controlled by a push button.

A shutter should be a mechanical device that puts something solid in the laser beams path to prevent it from escaping from inside the projector when it's not desired. A metal flag of some sort on the end of an actuator motor. YOU don't want to be in control of it with a push button. You want your software and hardware to know when to close it, as they know and can react FAR faster than you can to a problem with the system and prevent a stray full power beam shooting out when you don't want it to. What you DO want to have control of with a pushbutton, is an emergency stop button in case of a system failure, that shuts it all down.

Maybe I should just go big and buy a few DPSS lasers (if i can find decent price).Hah! I wish

With more and more people switching to diodes, DPSS is probably cheaper than you think since people want to get rid of the older technology and move to the more reliable diode. (That's my way of saying go with diode lasers - not unlike the blue I linked you to above.) But yes, you will find the older DPSS modules are starting to sell dirt cheap.

[Draco]

The form factor I am going with is the same that Bradfo69 posted, you can get just the housing http://www.ebay.com/itm/331528464834...%3AMEBIDX%3AIT

On that the brass needs to be pressed in, i have a hydrolic press for fireworks that i used as the little screw was not up to the task and made for a better thermal junction, that and the back screws out so your diode does not permanently become part of the housing, they come in TO38 and i think TO56. 3.8mm and 5.6mm.

for the driver on LPF, i would not use that on an expensive diode, cheapies would be fine. I am going for a single mode RGB in time but like you i will be getting green from DPSS laser, i have 5 so it's hard to cough up the green for 520nm green