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Thread: Diecimila Qs

  1. #31
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    Re: Diecimila Qs

    .025 is typical. They feel loose but pulling back a little on the wire "sets" the connection. They're pinch-pins internally so they kinda grab the wire when you pull back a little. The 20 AWG junk I buy at radioshaft and use frequently varies from 0.0247 to 0.0262 according to my trusty digital mic. (sampled six rolls)

    [edit] Just noticed you were using 24 gauge - yeah, that's a little small. 20 is just right.

    Just checked the table: 20 is listed as ~.032 - man, Radioshack is running a little light on their copper... Regardless, 20 is what I've always used for breadboards since the beginning of time, and they're designed to mate-up, so I'd say go for 20 AWG
    Last edited by Adrenalynn; 09-17-2008 at 12:47 PM.
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  2. #32
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    Re: Diecimila Qs

    I had to run the numbers about fifty freaking times to get some consistent results, but it appears radioshaft's 20 AWG is really about 22 AWG...
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  3. #33

    Re: Diecimila Qs

    Quote Originally Posted by Adrenalynn View Post
    it appears radioshaft's 20 AWG is really about 22 AWG...
    I am shocked, shocked that Radio Shack would skimp on something.

    I note that the Diecimilla board is sold as a kit. Two questions:
    1) How does one go about holding a surface mount component in place while soldering it?
    2) How in the world do you solder the tiny leads on the FTDI chip? The spacing between them is
    about .015". Do they make soldering irons and solder the diameter of sewing needles?

    EDIT: I found some answers!
    1) If you put solder paste on the pad, you can hold the component with tweezers and touch each pad with the iron.

    2) There are three methods that I found:
    a) Tweezers, a stereo microscope, a soldering iron with an SMD tip, .3mm solder and a steady hand.
    b) Run a heavy bead down the contacts then remove the excess with solder braid.
    c) Solder paste and an air flow iron.

    A SSOP chip is oriented by soldering pin #1 until centered on the pad, then the last pin on the other side, then the remainder of the pins.
    Last edited by BillSlugg; 09-17-2008 at 11:00 PM.

  4. #34
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    Re: Diecimila Qs

    Quote Originally Posted by BillSlugg View Post
    I note that the Diecimilla board is sold as a kit. Two questions:
    Huh? I'm pretty certain every Diecimilla board out there is sold fully assembled and for only $34.95

    http://www.trossenrobotics.com/ardui...-io-board.aspx

    There are some other knock-offs that may be harder to use, but the original is still fully assembled.

    -Fergs

  5. #35
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    Re: Diecimila Qs

    I think Bill just misspoke. The Diecimila comes preassembled, but there are a lot of kits/clones out there. The "original" wasn't the Diecimila - it was the serial version. I haven't seen any kits requiring surface-mount assembly - but they may exist.

    There are numerous ways of soldering surface-mount chips. JonHylands has a tutorial in the tutorials section here using a modified toaster oven for masking and reflow. For small jobs, I use a hot air rework gun (the Aoyue 2702) and solder paste. If you have just a temp controlled pencil, the method is to tack down one pin, then lay a bead of solder shorting all the pins across the pads. Then lay down solder wick (copper braid) to suck up all the solder. Surface tension will hold the solder under the pins to the pads and only the free floating solder will lift onto the wick. But an ESD-safe temp controlled iron is an imperative.

    After using that method, I throw the board under an Orion/Imaginova (familiar, Bill? ) digital microscope and look to make sure I haven't left any pins shorted.

    I could write a tutorial on that - after I finish all the multitude of crud on my plate - and I'm a good three or four months behind right now...

    I think there was a pretty good tutorial over on SparkFun, let me see if I can find it:

    Yeah - check this out: http://www.sparkfun.com/commerce/tut...utorials_id=36
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  6. #36

    Re: Diecimila Qs

    Yes, you are correct. Diecimilla clones run about $24. The FS232 chip is already soldered on there. Then there are roughly 30 through hole components to deal with. For a $10 savings it hardly seems worth it.

  7. #37
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    Re: Diecimila Qs

    Don't let that discourage you though... You can build circuits around the ATMEGA 168 with no more than two or three components, none surface-mount. You can even get the '232-USB chip in socketed through-hole. And if you're not trying to communicate with the outside world, you can ignore the serial entirely.
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  8. #38
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    Re: Diecimila Qs

    There's also the clones that use the usb/serial chip on a seperate board, thus saving space/power on the main board. Some use a special usb-ttl cable that has the FTDI (I think) chip embedded in it. See LadyAda's Boarduino, RBBB, and the Sanguino.

    The cable thingus costs twenty bucks, but you only need to get one, since it's not built into the board. The Boarduino is $17.5, unassembled, and doesn't have any surface mount stuff to it. The RBBB is similar but can be trimmed down even further if you don't need the power jack and regulator on it too, and costs $12/kit.

    For real jollies check out this instructable. Like Adrenalynn said, just a small amount of components are needed to make an "arduino". If you get/have the usb-ttl cable mentioned above, you've still got your serial connection as-needed.

    edit = Would a homemade one be a pseuduino?
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  9. #39
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    Re: Diecimila Qs

    I've run into an odd situation with the Wiring software servo library. I had been testing with S3003 servos which had worked fine, but when I swap in a Futaba S9405 it starts behaving strangely. It will turn a little in response to changing the pulse width, but then it stops responding. If I wait it will twitch a few times, and then become responsive briefly, but then will fail again in the same way. When I test the same servo on an RC receiver it works fine.

    I've never seen this behavior before. Anyone know what it means?

  10. #40
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    Re: Diecimila Qs

    Quote Originally Posted by metaform3d View Post
    I've never seen this behavior before. Anyone know what it means?
    I think I can answer my own question. It looks like the voltage was too low. It's spec'ed to run at 4.8v, but it was much happier at 6v. At 5v it had weird dropouts, but at 6-6.5v it performed without problems.

    Again if anyone has any other info it would be welcome.

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