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Thread: Fog machine help?

  1. #1
    Join Date
    Nov 2007
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    Default Fog machine help?

    Yes, I need to buy a hazer

    But for now, I have an issue. I've probably posted about it before, but I need some idea's.

    Basically, whever I run my fog machine near my laptop (eeepc), whenever you trigger the fog machine, it knocks out the USB communication. It doesn't effect my keyboard or mouse, however, but Arduino's, FB3, Moncha, DMX USB etc all loose communication.

    The similarity between all those devices? They all use some sort of USB to serial converter!

    I'm trying to figure out the easiest way to stop this from happening, but not knowing what causes it is problematic when trying to fix something

    Cheers,
    Dan

  2. #2
    Join Date
    Dec 2007
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    Nottingham, UK
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    Default

    Move the fog machine; or shield your cables!
    - There is no such word as "can't" -
    - 60% of the time it works every time -

  3. #3
    Join Date
    Nov 2007
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    Southampton, UK
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    Default

    The easiest way to prevent this is to run all the computer kit, and the laser, (but not the fog machine!!) from a UPS (Uninterruptable Power Supply). This not only filters out a lot of mains noise, it also lets you keep your laser running for a few minutes when a DJ spills his beer into the mixer and trips the mains power!
    Something like this : http://cpc.farnell.com/trust/pw-4100...ust/dp/CS15665
    won't break the bank.

  4. #4
    Join Date
    Mar 2010
    Location
    Phoenix,Az
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    285

    Default fog help?

    Dear Dan,
    I use several fog mechs my self and have never had that problem, I am sure your fogging unit dose not connect to the laptop unless this is the case, I belive your having an EMI problem, Check the fog pump with a DMM to see if your faulting to case ground turning the fog units case into an AC electro magnet,(even aluminum will dipole when electrofide).
    you can also test this by putting a small bar magnet to a peace of string and suspend it in air near by the fog unit, then push the fog button and see if the magnet that is suspended is effected meaning attraction or repulstion or both, The magnet should not move, not even a little bit. I hope this helps solve your problem. Please let me know what you find out.
    Emory Parker
    BEAMANN (GODSLIGHT SHOWS)

  5. #5
    Join Date
    Nov 2009
    Location
    Maryland
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    320

    Default

    +1 on the EMI problem but I would also question whether your fog machine and laptop are on the same circuit. For reasons I am not fully versed in we have had computer problems when a fog machine is shot on the same circuit as a lappy. It could have something to do with the massive draw of your typical 13A fog machine. I would suggest separating the circuits if you have not already.

    Separately I am a huge proponent of the American DJ Haze generator. If I had my druthers I would use that all the time over Martin, LeMaitre and pretty much anything else. The DF50 is great but is often too dense. It is a budget machine, I know but I have owned at least a dozen of them over the years and have always gotten my money's worth and thensome. All of our product videos are shot using that unit.

  6. #6
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    Default

    My cables can't really be any more shielded, USB standard requires shielding.

    I also suspect an EMI problem. I have tried putting chokes and EMI filters in the machine to no avail, and sometimes moving the machine away is not possible.

    The fog machine is only a small 700W unit, which is fine for my needs, so I wouldn't think the power surge would be that great?

    Maybe I need to do some tests on the pump as well.

    Also, it still has the same problem if I even unplug the laptop from the charger

  7. #7
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    Jul 2008
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    My momentum is too precisely determined :S
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    Default

    Yeah, I have that problem too with my cheap 700 W fogger. I can even get small battery-powered toys to work just by putting them next to the fog machine and press the button.
    The best thing you can do is setting your fog machine at the hugest distance possible.

    It really depends on the location too. I had a gig and my fog machine was under the stage, in the middle while my laptop was at the side of the stage. I didn't had any problems with interference whatsoever. I guess the stage acted as some sort of Faraday cage or something, or the distance was too big.

  8. #8
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    Default

    There shouldn't be much of a current surge when you hit the fog button, you are only triggering a small pump.

    The pulse is probably eminating from the remote control wiring, maybe decouple with a transistor controlled relay?
    http://img62.imageshack.us/img62/3985/laser.gif

    Doc's website

    The Health and Safety Act 1971

    Recklessly interfering with Darwinís natural selection process, thereby extending the life cycle of dim-witted ignorami; thus perpetuating and magnifying the danger to us all, by enabling them to breed and walk amongst us, our children and loved ones.





  9. #9
    Join Date
    Sep 2008
    Location
    Rocklea Brisbane , QLD, Australia
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    Default isolate the romote as cause

    Try pressing button on fogger direct with out remote attached and see if problem persists.

    If it stops it would indicicate the remote is the cause.

    try moving the unit away and see what is the reang of the interference, it it related to the proximity of the unit or where the poer is coming from.

    Also open the fogger and inspect, there are only two main components heater and pump you should be able to see if any wire is loose or not connected well.

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