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Thread: Can you use a beam splitter to combine beams?

  1. #21
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    Quote Originally Posted by TechJunkie View Post
    1. Can you recommend a good 20K galvo?

    2. Speed up the galvo later? Do you mean replace with a higher speed galvo later, or physically turn up the speed? I have no idea how to tweak galvos.

    3. You said "Good optimisation of scan route will get the best out of them, and teach stuff you can use later too." I have no idea what you are talking about. How do you optimize a scan route? Are you talking about beam alinement on the galvo?

    No, I dont have an amp, but that a great idea. I'll keep my eye out for one.
    Neighbours with junk in garages, car boot sales... I used to do repairs for second hand shops. Always good for useful tat, that is. That was one of the perks that vanished with the rise of eBay, but you might get lucky, especially if you know any local bands.

    Optimising scan route is like the 'travelling salesman' problem. (Google has more than enough info on that one). It basically means that if your software (or you) can deduce a faster way to cover all drawn points in a show frame, you might get it lookign nice with clean lines and reduced flicker. This applies at any speed so it's worth doing.

    I can't advise a galvo choice because I don't know them well enough to do it, but lots of people do. The thing to know right now is that to double the speed, the effort needed to accelerate it more than doubles (goes up by the square of the increase I think). So a 30K scanner must have bigger heatsinks and stronger amps, better thermal and mechanical design. Bill Benner's posts (as Pangolin) go into that a lot, well worth reading, and check out his videos, those save time when learning this. 15K to 20K is so easy loads of makers do it. 30K is hard, true 60K is REALLY hard. The demand change to force a 60K scan is 16 times harder or so than for a 15K scanner, which is why the amps and moutings are so big, and it all gets very expensive. So if you're looking for budget, go for 20K because the expense drops a LOT faster than the performance! Just get some recommendations for accurate ones, especially for accuracy for small detail like text.

    Just consider the 30K galvos too, physically, so your projector can easily take them if you upgrade later. Also, you might do better going for a whole basic 20K projector if it's cheaper than building from parts, then start replacing its dodgiest parts with better ones. That recently got to be a base plan for many people because there are so many of them now.

  2. #22
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    Great, thanks for the pointer Doc. I'll do some reading.

    I'm a DIY guy. I know I could have bought a cheap projector, but I want to make my own.
    “Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind.” ― Bernard M. Baruch

    "They that can give up essential liberty to obtain a little safety deserve neither liberty nor safety."
    ― Benjamin Franklin; stairwell plaque in the Statue of Liberty

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  3. #23
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    Quote Originally Posted by TechJunkie View Post
    Great, thanks for the pointer Doc. I'll do some reading.

    I'm a DIY guy. I know I could have bought a cheap projector, but I want to make my own.
    Cool, points earned for wanting to build your own, you will learn much more and be much better off doing so. You can upgrade bits as you progress and want more, it can be never ending but that's not a bad thing right?

    I am sadly considering selling my entire laser rig as funds are drying up and in 5 months I have been unable to find a position with a company I like, so watch out in the buy/sell forum for a sale thread real soon.
    This space for rent.

  4. #24
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    Dnar, if you hang around here you might get some freelance work. Very uncertain but it could be worth holding out for. Incidentally, while I do not have much money at any time, I'm interested in a small fast embedded board that can run 32 bit code at a few hundred MHz, with audio out, and MIDI in/out. The aim is to run my polyphonic phasemod synth on dedicated hardware. I have no idea what the cost of such a project would be but I suspect it might be something you can do. I'm interested in any thought you have about that. The synth currently runs on W98, with very few dependencies as it's built in ANSI C and uses only Winmm.dll for the Win32 API access to ports. The GUI will remain small, likely something that can be drawn on a high-res PDA screen, but I'm equally happy with no screen at all, so that a computer programs it via MIDI, then it becomes a standalone module under other MIDI control for performances. So basically a very minimal but solid little synthesiser that packs a much bigger punch than the DX7 ever did. What I hope is possible is that I can avoid any complex host OS and make it pretty much the only thing running on the hardware, in which case I'd gladly forgo the GUI code for this project.

    TJ, I had another thought for projector building... If you get the 1/8'' thick angle section aluminium, 3/4'' wide, you could cut it to form edges to bind fairly thin plates of alumium by drilling 5mm holes and using a pop riveter, same way that flight cases are built. The heavy plate wants far better fixings, but you could build the entire top this way, and also the bottom section that contains a big slow fan for cooling. It's fast, cheap, and if you end up with nice methods for quickly making the edges from that angle section stock, you could get money for rapid prototype builds for people.

    I learned this possibility when I wanted to modify a flight case to fit that tiny 1U rack computer I built. It amazed me how cheap the rivets and riveting gun were, and how easy and fast it is to get a good result. With 3mm thick aluminium sheet the result might be very strong too. Better yet, there are various flight case sheets that are composites of aluminium and wood, or black plastic. If you can get them cut by the seller, you might solve all kinds of DIY build problems and also get a very high quality result.
    Last edited by The_Doctor; 02-19-2014 at 06:33.

  5. #25
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    You might want to get the right coating for the right wavelength.
    Check ebay they are actually are like 15$ a piece for 445nm or 635.

  6. #26
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    Quote Originally Posted by dnar View Post
    Cool, points earned for wanting to build your own, you will learn much more and be much better off doing so. You can upgrade bits as you progress and want more, it can be never ending but that's not a bad thing right?

    I am sadly considering selling my entire laser rig as funds are drying up and in 5 months I have been unable to find a position with a company I like, so watch out in the buy/sell forum for a sale thread real soon.
    I've always been a hands on man. I also like the fact that I can design, then create my own stuff. I know it will be right, and it makes it easier to work on later because I dont have to deal with someone elses mass produced shit work.

    Wayne its really sad to hear you may have to sell your stuff. I've been there many times in life. But dont fret, its just stuff, and often times you can get better later on. I cant afford a whole rig, hell I cant even afford a decent set of galvos yet. So I doubt I can help you out. The next parts I'm looking for are 3 analog drivers. If you have a set laying around PM me and we can work something out.

    Quote Originally Posted by The_Doctor View Post
    TJ, I had another thought for projector building... If you get the 1/8'' thick angle section aluminium, 3/4'' wide, you could cut it to form edges to bind fairly thin plates of alumium by drilling 5mm holes and using a pop riveter, same way that flight cases are built. The heavy plate wants far better fixings, but you could build the entire top this way, and also the bottom section that contains a big slow fan for cooling. It's fast, cheap, and if you end up with nice methods for quickly making the edges from that angle section stock, you could get money for rapid prototype builds for people.

    I learned this possibility when I wanted to modify a flight case to fit that tiny 1U rack computer I built. It amazed me how cheap the rivets and riveting gun were, and how easy and fast it is to get a good result. With 3mm thick aluminium sheet the result might be very strong too. Better yet, there are various flight case sheets that are composites of aluminium and wood, or black plastic. If you can get them cut by the seller, you might solve all kinds of DIY build problems and also get a very high quality result.
    I'll keep that in mind Doc, thank you. I'd need something to make clean cuts, like a bandsaw. I dont have one but the summer is coming, which means flea market deals. So it might be a good future venture for me.

    Quote Originally Posted by masterpj View Post
    You might want to get the right coating for the right wavelength.
    Check ebay they are actually are like 15$ a piece for 445nm or 635.
    Thanks for the tip PJ. When I upgrade to 635 I'll grab the proper cube.
    “Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind.” ― Bernard M. Baruch

    "They that can give up essential liberty to obtain a little safety deserve neither liberty nor safety."
    ― Benjamin Franklin; stairwell plaque in the Statue of Liberty

    "And so shines a good deed in a weary world." - Willy Wonka

    6 Steps To Prevent You From Getting SCAMMED On The Internet CLICK

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