Prototype construction techniques

Discussion in 'The Projects Forum' started by BillO, Feb 17, 2009.

  1. BillO

    Thread Starter Well-Known Member

    Nov 24, 2008
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    Hi All, couldn’t think of where else to ask this.

    What do you all use for prototype construction techniques? I guess most will generally use solder-less breadboards for the alpha-prototype so I guess my real question is, what do you all use for beta-prototype construction?

    Do you….

    Go straight to printed circuit (risky and expensive, especially with complex projects)?

    Use traditional point-to-point (through hole, top surface wiring. This is tedious, slow and sometimes less than stellar in result. This is what I currently use)?

    Wire-wrap (god help us all!!!)?

    Or do you use poly-urethane coated wire and wiring combs on the back of the board? Something like the Roadrunner wiring pen system? PU coating just melts with the heat of the iron. This method looks great, promises to be quicker and easier, but the stuff is so hard to find and source that it cannot be in high use.
     
  2. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
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  3. BillO

    Thread Starter Well-Known Member

    Nov 24, 2008
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    Yikes!!!!

    That's worse than the new Friday the 13th movie!
     
  4. studiot

    AAC Fanatic!

    Nov 9, 2007
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    You can apply surface mount (SM) (no quips or whips please) techniques to full sized components as well. No drilling or threading through holes required. Just mount the components on the copper side of the pcb with glue and solder.

    The usual technique with a pcb is to create (mask) small lands for the wires/solder joints and connecting tracks and etch away the rest.

    An altenative technique, suitable for the SM method above is to mark isolating lines or channels and score along these with a craft knife. This separates the copper into large lands suitable to solder component leads to and removes minimal copper. Some souls use a router to cut the separations.

    Sorry I don't have any photos, but you will find good descriptions of this and other methods in the Amateur Radio publications from both sides of the Atlantic. This includes Eric's rats nest method, which can be suprisingly effective if you pot the final circuit when you have it working to your satisfaction or she who must be obeyed calls you for (dinner).
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
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    It's hard to made an absolute reply that will be true in all cases. For logic, wire-wrap is very effective, but you're limited to what logic IC's are available in pdip cases. Don't think TFQP has a wire-wrap socket, and it would stop your heart to see what it cost.

    Wire-wrap is very flexible, though, and does allow a lot of changes to percolate through if needed.

    Analog is different. It comes in all flavors, and the successful technique may vary. Lots of stuff got built using point-to-point and terminal strips, but there are frequency limits. Rats nest over ground plane sometimes works.
     
  6. Audioguru

    New Member

    Dec 20, 2007
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    I have always made well-planned Veroboard prototypes and every single one was sold as a final product. All my test equipment is made on Veroboard. The wiring is neat and tidy.
    The Veroboard has parallel copper perforated strips that make half of a pcb and the components and a few jumpers make the other half of a pcb. Each perf hole has only one wire of a component so changing the component is easy.
     
  7. flat5

    Active Member

    Nov 13, 2008
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    Hello AudioGuru, I have not tried stripboard yet.
    I plan to soon. Do you use any special tools or just a drill bit and Exacto knife?
     
  8. Audioguru

    New Member

    Dec 20, 2007
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    There was a Veroboard strip cutter hand tool that was just a drill bit in a wooden or plastic handle. I gently cut the strips of copper in my drill-press. I don't use an Exacto knife.
    I made some very complicated and big circuits on Veroboard. 34" long by 36 strips wide.
    I used my brain, grid-paper, an eraser and a photo-copier to plan the layout.
    Now there are pc programs that I have not tried.
     
  9. eblc1388

    Senior Member

    Nov 28, 2008
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    Then there is the dead bug method. If you don't know what it means, just think of of a dead bug laying flat on the PCB, with all its legs pointing into the air.

    Then this is another one by the Japanese, using a tool called nezumi-ba kiri

    [​IMG]
     
  10. Dave

    Retired Moderator

    Nov 17, 2003
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    Likewise.

    We just made our own tool which was a 3/16" drill-bit glued into a wooden handle. Seems to work well, however you can buy a similar tool that achieves the same objective.

    Dave
     
  11. flat5

    Active Member

    Nov 13, 2008
    403
    17
    Thank you AudioGuru and Dave. Maybe I'll buy a Dremel drill set and stand if I become a more active builder. I'll go to a hardware store and see what drill holder options I find.

    This editor is driving me crazy!
     
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