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Thread: Heatsinking X-Drive Driver? For continuous operation/100% Duty Cycle?

  1. #11
    Join Date
    Nov 2010
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    Ilchester Somerset UK
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    60

    Default Plans for my laser lightshow projector & analogue modulation versus X-Drive

    Thanks for all your advice.

    I agree that it would be much better to do something properly at the start, so I am going to try to find a driver that would give me analogue modulation. I will still be receiving the X-Drive driver, but shall keep it for spares/testing later.

    So it would be possible to run my 445nm laser diode with analogue intensity control just by using a driver that supports analogue modulation?

    I had better explain my level of knowledge before detailing what I am trying to achieve. Then you can all see where I intend to go!

    The photo below shows my experience with laser displays; its of a 4W Argon gas laser...

    Attachment 41015Attachment 41016

    ... This was in 1985 when I worked for an entertainment laser company called Laser Systems of Cwmbran, Wales, here in the UK. The left (1st) photo shows the 4000mW Spectra-Physics Argon laser, which was split by a beam splitter into blue/green & green shown in right (2nd) photo.

    This right photo also shows the beam-stop in the blue beam, which is actually an R.S solenoid with a black bit of plastic on the end. This is the only blanking the system had; slow & crude with no means of fast control. So you can see that my experience of blanking is a little simplified. This photo also shows one of the analogue galvanometer driver circuit boards.

    The left photo finally shows the pair of General Scanning G120 Galvanometers providing X & Y axis scanning. Of course with no fast blanking, any scanned graphics or text had lines between their parts. We used to have to do text as handwriting as there was no means of blanking the laser between each character.

    Control was by special hardware control panel based on a Z80 microprocessor. The software was written in-house in Z80 assembler. The laser was powered from 3 phase mains (415VAc @ 50 Hz) drawing something ridiculous like 45Amps per Phase. Both laser & PSU were water cooled, & if the water was too cold, then condensation could form within the PSU, & if it formed on the pass-banks, then it could cause an explosion.

    The fragile argon laser alignment was often affected by the bass in the discos/night clubs, meaning that Service Engineers like me had to travel the globe adjusting the cavity mirrors to get the power back up!

    These 4W scanning systems cost approx £25000 in 1985 money, which was a lot! Way beyond my means!

    I moved into defence electronics at Westland Helicopters & the UK Ministy of Defence, but always wanted to run a laser Lightshow on the side, but could not afford such expensive systems.

    Then I recently discovered DPSS lasers. It seemed that as these operate at 532nm, they are much brighter than argon (watt per watt). And even a 1000mW DPSS laser could appear as bright as a 3 or possibly 4 Watt argon. Trouble is even as recently as 2007 even a 100mW green solid state laser would cost me more than £1000.

    However recently I was able to buy a secondhand 100mW green DPSS laser for £40! I didn't think I could afford galvanometer scanning, so I designed an arrangement of mirrors on steerable motors to give me flat scans/liquid ceilings & laser tunnels, & adjustable mirrors on solenoids to give straight beams onto target mirrors. But then someone on here sold be a pair of 15k galvos, complete with driver cards & XY block.

    I found a dual channel DAC based on a laptop parallel port, & dusted off an old Pentium laptop that had a parallel port. I found something called Popelscan so thought I have everything I need.

    I then discovered it was possible to build a 1000mW or even 2000mW 445nm laser module based on the M140 laser diodes from Casio projectors, which should be bright enough.

    I was only going to build a single colour system using my 100mW green laser, but now I am thinking of using the 100mW green laser too, but it might not be bright enough. I think I will probably need 1000mW of green with up to 3 or 4 times that amount of Red & Blue though??

    I have been rather wary of my DAC & the freeware Popelscan software though. Maybe it wont be fast enough. What I really need is an affordable DAC & control software. Maybe a more modern DAC, such as the products sold by Pangolin possibly?

    Or is there a more affordable open source solution? I have heard about DACs running on computer sound cards for example; but surely these are only AC coupled? I have also read about some LINUX based DAC that is cheap & another DAC by some chap called Fred!

    I have the draft ILDA Standard & some of their guidance notes including their pin allocation & design article concerning making the right connections. I will make my projector iaw the ILDA Standard, (athough as i'm working in military avionics & safety-critical electronics I am surprised that there are not more safety features built in, such as dual redundancy of critical signal paths & power supplies, & fast enough scan fail detection/shutdown. It seems if you lose even one of the scanner PSUs, then that galvo goes stationary at dead centre; a double PSU failure could result in a totally static & dangerous unspread beam! And I have always been mis-trusting of D type connectors; maybe I shall use an Amphenol multipin aircraft connector in mine!!)

    Not sure about the scan failure detection & how to quickly shutdown the laser. My beam power & safety calculations show that max permissible exposure level could be exceeded in as short a time as 20 micro-seconds; even detecting such a failure in that time would be difficult, let alone also shutting the laser down within that time too. It might be possible using a fast photodiode, coupled with fast TTL or faster ECL logic maybe. ( I don't want to get too tied-up with this though. Even with the way things were done back in 1985 & since has not resulted in many (if any) laser injuries here in the UK, where we permit audience scanning. The few injuries I have heard about over the years are almost certainly due to gross negligence, such as using huge pulsed lasers for example).

    So any advice on any of this would be most welcome, especially about analogue modulation of the 445nm blue laser combo I am about to buy from DTRs laser shop, & also any suggestions on the DAC/control software side of things too.

    Many thanks,

    Simon B.

    (P.s sorry if I have rambled on too much, & also if I've mixed mW & W, which is a bad habit of mine!)

  2. #12
    Join Date
    Feb 2011
    Location
    St. Louis
    Posts
    526

    Default

    The best method is to mount the X-drive to your heatsink by using thermal adhesive to attach the drivers IC to the sink. This will give continuous operation of the driver. Also the drive will run for 120 seconds with 8.4V input and drop down to the minimum input of 6V it would run for up to 5+ minutes at a time without overheating.

    As noted the X-drive is for uses that don't require modulation if you need modulation there is the Flexmod P3 that you can get from Illuminationsupply:
    https://illuminationsupply.com/laser...2ed1de1e5851a5

  3. #13
    Join Date
    Oct 2007
    Location
    Vancouver, Canada
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    327

    Default

    Coming from the days of the gas lasers and mechanical blanking with a galvo, I think you'll find the modern direct modulation to be a welcome change. There are two types available, ttl, and analog. Ttl is basically on and off, but capable of much greater speeds than a mechanical galvo type setup you're used to. Analog add intensity control, and is typically controlled via a 0-5V input. With 0V being off and 5V being the maximum current setting that you've set for the diode, and anywhere in between. This allows for shades of colours when mixing colours, but even beneficial in a single colour projector. Both generally just as fast, and plenty fast for modern galvo's, you'll likely never run into any issues of blanking not being fast enough.

    Nowadays, you'll likely find analog drivers such as the flexmod p3 dtr mentioned to be similarly priced to ttl drivers which are typically only now see in chinese made lasers and ebay. So it's always worth just going for analog to start with as you'll likely be wanting it down the road anyhow.

    For 1W of 445nm, opinions will vary, but I find 1W of 532nm to mix just fine. 100mW will likely not be enough to balance 1W of blue, so you'll need to turn the blue down initially to get a good balance. And with any luck your 100mW green will be analog modulated as well. Check out goldenstar lasers when you're ready for an upgrade as they have some great prices on green's and you might find something in your price range. As far as how much of each colour, opinions will vary, but using 638nm red rather than the deep 658nm red, I find a 1:1:1 ratio works well. Can fine tune from there.

    One thing you'll find with the 445nm diode vs the old argons is the beam quality is not nearly as nice. Instead of a nice clean tight dot, it's output is more of a stripe. This can be corrected quite well with optics. There are vendors around here who have anamorphic prism sets and cylindrical lens set available that will clean that up nicely.

    The 15Kpps scanners will get you started, but I have a feeling you'll be craving more soon enough. For the budget minded builds I really like the DT30's, also available at goldenstar. They do also have cheaper scanners, and also much faster / higher end scanners but in general the dt30's seem to be about the best compromise if looking to keep costs very low.

    The community seems to be split on opinions about software. There is a following for both LSX and Pangolin, and both have their advantages. However both will cost a bit to get into. There's not too much out there that is of good functionality when it comes to free / open source. Some of the others here might be able to direct you better on this, as I went straight to a Pangolin setup. There are arduino based dac that can be built, sound card dacs, etc. But in the end most will upgrade away from those as they're just a bit too limited, and also the safety aspects. So best not to spend too much on those and just save for a proper solution. Pangolin tends to be used more commercially for shows, whereas lsx is more often used by enthusiasts. Both will cost roughly the same to get into, I believe lsx might be just a bit cheaper but in the end both are close to the $400-500 range.

    Regarding scanfails. There are some fast ones available but tend to be pricey. If doing shows commercially it's a good idea of course to have, and absolutely necessary if audience scanning. Many will use a beam block / aperture mask instead and just keep all beams overhead. Pangolin PASS is about 1ms but expensive. There are others in 20-25ms range that are quite a bit more reasonably priced $100-200 range. And finally goldenstar has one for $31 that's closer to the 100ms range, which is certainly better than nothing, but not to be used for audience scanning.

  4. #14
    Join Date
    Jul 2005
    Location
    Lancashire UK
    Posts
    1,379

    Default

    Hi Simon
    I remember seeing that Advert in "Disco international Magazine" in the 80s ...
    I was quite suprised at the time ... know how much those systems cost and seeing how crude the system was in the advert ... ( solinoid cabletied to a bit of dexion )
    but i went to the Laser systems stand and one of the trade shows in london and was blown away by those desks that they made ... ( magnum i think )

    welcome to the forum mate ...

    Karl

  5. #15
    Join Date
    Nov 2013
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    State of Shock USA
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    608

    Default

    Quote Originally Posted by DTR View Post
    The best method is to mount the X-drive to your heatsink by using thermal adhesive to attach the drivers IC to the sink. This will give continuous operation of the driver. Also the drive will run for 120 seconds with 8.4V input and drop down to the minimum input of 6V it would run for up to 5+ minutes at a time without overheating.
    Interesting. I've run them up to ~10 minutes without any heat sinking, and it just got warm. It was attached with 4" leads to the diode. Could the leads have anything to do with it?
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  6. #16
    Join Date
    Nov 2010
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    Ilchester Somerset UK
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    Default

    Thanks for the various replies.

    Laser System used to make the Maestro & Magnum controllers. The Magnum was an angled control panel on a stalk, which could move/flex about a bit. These were quite comprehensive controllers, especially as this was the pre-PC era of hardware controllers!

    m0f kindly suggested Goldenstar Lasers, & their prices are very attractive (£124, £290 & £112 for a 1000mW Red, Green & Blue CNI lasers respectively)! These are the most attractive prices I have ever seen, although analogue modulation may be extra.

    Does anybody know of any UK suppliers of CNI lasers? Although the Goldenstar website quotes me £16 for international shipping.

    I have not seen a live lasershow for a few years or so, but has the situation regarding audience scanning changed here in the UK? It always used to be tolerated here providing the installer/operator undertook comprehensive measurements & calculations (I can remember writing documents for each effect per venue in which calculations showed beam power/area was generally below a mW per square centimetre). Such analysis would not be enough for modern Safety-Case assessments, but back then it exceeded what the guidance at the time (PM19) stipulated!

    Thanks everyone,

    Simon B.

    - - - Updated - - -

    Thanks for the various replies.

    Laser System used to make the Maestro & Magnum controllers. The Magnum was an angled control panel on a stalk, which could move/flex about a bit. These were quite comprehensive controllers, especially as this was the pre-PC era of hardware controllers!

    m0f kindly suggested Goldenstar Lasers, & their prices are very attractive (£124, £290 & £112 for a 1000mW Red, Green & Blue CNI lasers respectively)! These are the most attractive prices I have ever seen, although analogue modulation may be extra.

    Does anybody know of any UK suppliers of CNI lasers? Although the Goldenstar website quotes me £16 for international shipping.

    I have not seen a live lasershow for a few years or so, but has the situation regarding audience scanning changed here in the UK? It always used to be tolerated here providing the installer/operator undertook comprehensive measurements & calculations (I can remember writing documents for each effect per venue in which calculations showed beam power/area was generally below a mW per square centimetre). Such analysis would not be enough for modern Safety-Case assessments, but back then it exceeded what the guidance at the time (PM19) stipulated!

    Thanks everyone,

    Simon B.

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