Spraying the mikrokopter boards

Discussion in 'Electronics' started by Lauri Hakala, Sep 27, 2012.

  1. Tommy - KnightDesignDev

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    That is a very fine work instruction Andy, Impeccable job !
    I used to make these same type of docs for our CCA manufacturing teams.
    I was going to do the same after I add my LED / Buzzer / 5v Expansion cca.
    Thank you for the mass of time you invested in this, you are very gracious.
     
  2. Joe Azzarelli

    Joe Azzarelli Active Member

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    Andy
    I used Fine-L-Kote™ HT Silicone Conformal Coating. Is there a reason you prefer the acrylic?
    Just wondering...

    Also, as you noted in para. 11 of the RGGtSTMBwCAS, I did my small boards by spraying into a plastic cap and brushing on. Any downside to this vs. spraying?

    Joe Azzarelli
     
  3. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    @Knight: My pleasure -- glad it's of use to you. Yeah, it took me the best part of two days to get it right -- and that was with Wolfgang doing the images for me too -- which must have taken him some time as well. Edit: And Wolfgang made a couple of editing passes through the drafts too!

    @Joe: I've had a very uneasy relationship with silicone sprays/coatings as they have often proven to be very hard to remove when I needed to remove them. The acrylic is easier to remove -- especially you need to solder to a pad -- you can just burn it off with the iron. I'm not sure that's true for silicone.

    As to painting/spraying -- I chose to spray because I thought it would be more pervasive, that's all. That said, you can probably get a thicker coating with a brush.

    Andy.
     
  4. Gustavo Rios

    Gustavo Rios Member

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    Hi Andy, good job !
    Tell me, is not one cleanliness necessary before ? maybe a small brush for the dust or a q-tip with alcohol or some spray cleaner, this last would not use it but I'm no expert on this.

    Gustavo.
     
  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Gustavo:
    Good point -- yes, I would certainly clean the boards by using compressed air to blow the dust off -- you really don't want to seal the dust under the spray. I'll add that to the document the next time I have a chance to edit it.

    Thanks
    Andy.
     
  6. Josh Lambeth

    Josh Lambeth Well-Known Member

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  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Josh:
    Looks interesting, but I don't think the product is on the market yet -- certainly, if it is, it's not by that name and Mrs. Google doesn't know about it.

    Andy.
     
  8. Wolfgang Armin

    Wolfgang Armin Active Member

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    After spraying the boards, I do now have a problem with the navi.
    I get the errors: Error4 No compass communication and Error6 bad compass values.
    I guess Error6 is a result of Error4, because if you can´t communicate you don´t get any values at all.

    From my understanding it wouldn´t make sense to calibrate the compass when there´s no communication. So I try to ask you guys before that. Any ideas what could cause the problem? The compass sits on the NaviCtrl (2.0), so spraying shouldn´t have any influence. There don´t seem to be a lot of error4´s, google didn´t turn up some useful info.
    I masked everything and also used the spray with the UV indicator, under UV light the masked areas don´t show any sign of coating.
     
  9. Wolfgang Armin

    Wolfgang Armin Active Member

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    Here´s an update. Just decided to give calibrating a try, but I didn´t even hear the weird sound when starting to rotate the copter. I continued nevertheless, but I´m still having the same problems.
    Would be great if anybody had any idea.
    All items are having power, GPS, NaviCtrl, FlightCtrl and Powerboard.
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Wolfgang:
    Just on hunch, this sounds more like a wiring problem. Can you re-seat all the connectors between the boards and try again. There is a very slight chance that some spray got where it shouldn't and perhaps one of the mini-molex or ribbon cable connectors is bad, so you might try disconnecting and reconnecting a few times to see whether than cleans the contact surfaces and changes the problem.

    I'm concerned that you're not even getting into compass calibration -- do you get an initial beep to confirm that you're even in compass calibration (before the rotating step)?

    Andy.
     
  11. Wolfgang Armin

    Wolfgang Armin Active Member

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    Hi Andy,
    yes, I get all the beeps during calibration. I will try to change molex cables, etc. Let´s see what that will bring.
    Thanks for your help.
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Wolfgang:
    OK on the calibration. The other procedure you might try, just to simplify the problem, is this:

    1. On the Navi board, disconnect the ribbon cables from the Flight Control board.
    2. Put the two pin jumper on the MK USB Adapter so that it will provide power.
    3. Connect the MK USB adapter to the Navi Control board.
    4. Start up MK Tool -- do you still see the error? If so, then it's definitely confined to the Navi Board/GPS board and/or the compass on the board and is not something caused by the NC board. (I don't think it is being caused by the NC board, but it's worth checking).
    5. If you see the error still, then disconnect the MK USB adapter from the Navi board.
    6. Disconnect the Molex connector on the Navi board to the GPS board (thus removing it from the situation).
    7. Then re-connect the MK USB board to the Navi board -- now it's ONLY the Navi board that has power.
    8. Does MK Tool still show an error in the center green text window?

    I'm not quite what I'd do after that, but we'll cross that bridge if we come to it.

    Andy.
     
  13. Wolfgang Armin

    Wolfgang Armin Active Member

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    Hi Andy,
    thanks for the tips. If I remember right, I did all those suggested steps. The error was still there.
    Time is running (and is money ;-)), so I ordered a new set of GPS/NaviCtrl. This should help identify the problem.
    That will also almost complete my set of spare parts (if the navi-control will ever work again) except for one more motor and 6BL-ctrls which isn´t a bad thing either.
     
  14. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Wolfgang: You might also want to consider the possibility that one of the cables has gone bad. Often the physical act of removing a cable can cause problems -- especially those ribbon cables which do not have a locking clamp on the plastic plugs on the end.

    You might want to gently squeeze the plastic plugs, forcing the back of the plug to crimp down on the ribbon cable. [Edit: I use a small vice to squeeze the ribbon cable plug to make sure the plug is on securely.] The metal pins on the plug that cut through the ribbon cable insulation to make contact with the individual wires sometimes don't make good contact.

    The other possibility might be the mini-Molex connectors (small white plugs between FC and PDB, and GPS and NC boards. Inspect those carefully just in case there's a broken wire.

    Let me know what you find, please.
    Andy.
     
  15. Wolfgang Armin

    Wolfgang Armin Active Member

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    Hi Andy,
    thanks again for your support.
    I´ve just changed the new NaviCtrl for the old one and Error4 is gone. Error6 is still there of course since I had no time to calibrate.
    Would be great if I could get the old NaviCtrl up and running again, but I don´t know how and what could be the problem.
    Since I´ll leave in a few days and don´t want to risk anything again I´m thinking about using a shrink tube to give it some protection (cutting out the connectors). I don´t think the NaviCtrl will get too hot, will it?

    Cheers,
    Wolfgang
     
  16. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Wolfgang:
    I don't know enough about the Navi Control board's thermal characteristics to be able to answer, I'm afraid. I would be more tempted to wrap it in "Saranwrap" (otherwise known as "cling film" for wrapping food, etc.). Its so thin that it will conduct heat away -- I worry that heat shrink might cause things to overheat.

    Andy.
     
  17. Wolfgang Armin

    Wolfgang Armin Active Member

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    Andy always has great tips - me happy ;-)
     
  18. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Veilen dank, Wolfgang.
     
  19. Ryan J. Rowe

    Ryan J. Rowe Member

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    Hey Andy,
    I just received my can of conformal spray. I must have ordered the urethane because that's what I have. Is this OK to use or should I re-order the Acrylic instead? Thanks for the great document on masking and sprayin!
     
  20. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    That's a very good question, Ryan. And not one I know the answer to, so I did a Google search using:

    acrylic vs urethane conformal coating

    There seems to be quite a lot of information out there.....sorry...bit rushed this am so I've not had a chance to read it.
    Would you be kind enough to post an answer when you find it, please? I'd like to know! :)

    Andy.
     

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