Help with PCB Design

Discussion in 'The Projects Forum' started by chrispedersen, Nov 5, 2013.

  1. chrispedersen

    chrispedersen Thread Starter New Member

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    Is there anyone willing to help out on PCB design - 13 switchs/potentiometers, coin battery, and a capacitory. Something that if someone knew what they were doing they could probably knock out in a couple of hours.

    LOL.. whereas I'm struggling on the circuit design, best practices AND software.

    Help much appreciated!

    Chris
  2. DerStrom8

    DerStrom8 Well-Known Member

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    I'm sure you'd be able to do it just fine. I suggest downloading a free program like EAGLE or FreePCB and trying the layout yourself. You'd be surprised how fun and simple it could be. I'd be happy to help you out if you have any questions about the design process itself. What do you say? Care to give it a try?

    Regards,
    Matt
  3. tracecom

    tracecom Well-Known Member

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    It's possible that someone here would help, but most would want to see a schematic, a parts list, and the board size and shape constraints first.
  4. chrispedersen

    chrispedersen Thread Starter New Member

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    Oh yeah. I've already downloaded eagle. Already worked through a couple of tutorials. I also found an eagle representation for IC chip I'm using and I've (somewhat?) figured out voltage divider circuits.

    So.. I am making an effort.

    I also tried a lot of the same things with the artist software. But in the end did'n't want to be tied to the vendor.
  5. DerStrom8

    DerStrom8 Well-Known Member

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    Glad to hear you're trying it on your own!

    That's the main reason I use Eagle. You can export the gerber files and send them to a manufacturer of your choosing. You're not obligated to use any single service, like you are with programs like ExpressPCB.
  6. chrispedersen

    chrispedersen Thread Starter New Member

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    Well, here's what I (think) I've figured out.

    1.5x2.0 inches
    2 ply rigid 1 oz copper
    8 mil traces
    15 pins
    1 cc2541 surface mount chip (have the library for this)
    1 coin cell battery
    1 47uF capacitor
    2x1uf filter cap
    15 x 27KΩ resistor.

    Things I don't know:
    Basically, I'm reading a bunch of sensors and transmitting data via blue tooth, so there are restrictions on things being in the plane of the antenna.
    Will I need capacitors to smooth the inputs?
    Will the voltage throught the sensors 'drive' the IC chip?
  7. tracecom

    tracecom Well-Known Member

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    From the parts list, it sounds like a fairly simple board; post a schematic when you have it. Even a hand drawn schematic would be good. You would also be wise to breadboard the circuit and test its operation before going to PCB.

    DerStrom8 and I use different software. I tried to learn Eagle and gave up; DipTrace works for me.
  8. elec_mech

    elec_mech Senior Member

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    I'll throw my two cents in here.

    I use ExpressPCB to design a circuit but I use Futurlec to make the boards since they will accept ExpressPCB files and the boards cost much, much less.

    I've used Eagle once and attempted Diptrace. Eagle took me some time to learn and I'd have to relearn it again as it's been a few years. I just don't like the cost of the program. If you need a big board, you pay more for the program. Not sure if that still holds true. Diptrace also felt a bit time-consuming to learn based on the 5 minutes I spent with it. Not to say either are bad - both offer far more options than ExpressPCB and you can take their files to ANY boardhouse.

    Since I'm inherently lazy, I like being able to sit down and design a simple PCB without thinking about it too much, hence ExpressPCB. Just wanted to let you know you can use the simple program and still have the boards made without paying an arm and a leg.
  9. SgtWookie

    SgtWookie Expert

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    Breadboarding is not an option, as not only is the CC2541 in a tiny 6-mm × 6-mm QFN40 package (less than 1/4" square with 40 connections!), it requires an RF antenna, which will likely be easiest to design into the board itself. A full wave antenna would be 12.5cm, or ~4.921"; but half wave or quarter wave would be more common.
  10. elec_mech

    elec_mech Senior Member

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    SgtWookie makes an excellent point - I didn't realize this was for an SMD IC. So that brings to question - how are you planning to solder the IC to your board or do you plan to put this through a reflow oven?

    Alternately, have you considered buying a development board to experiment with first? Found this on Google. Not that I'd buy that one from that eBay vendor, but there appear to be a few pre-built boards with the CC2541 already on them.
  11. John P

    John P Senior Member

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  12. chrispedersen

    chrispedersen Thread Starter New Member

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    Thanks for the great advice. I'll try to answer the questions.

    Regarding SMD.

    Yeah, its an absolute hard that this isn't available in a pin through configuration. I am looking at a module variant that includes an antennae.

    I have been studying the reflow, but I thinkI'm going to try to go the solder paste and stencil route. There were a couple of good tutorials on u-tube for that.

    The solder paste / stencil route was one of the reasons I liked eagle - as I found a tutorial that showed how to export a solder mask for the pads.
    Does the alternate software proposed have that ability too?


    (And believe me - if I'm saying something wrong - advice appreciated because .. well I have no practical experience in this.).

    By the way, is there a way for this site to forward when a response comes in - I'd like to get notified so I can reply more promptly.
  13. chrispedersen

    chrispedersen Thread Starter New Member

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    Advice on the vendors is much appreciated.

    In researching this, my top three choices were
    Barebonespc.com - where it looks as if I can get 3 boards for $100 as a student.
    Goldphoenix - just to support sparkfun. Again cost around $100
    BarchPCB. Since the research said it was $10 + 2.50 per square inch and I'm looking for a tiny board.
  14. chrispedersen

    chrispedersen Thread Starter New Member

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    Regarding the bit about the breakout board - I like it a lot. I was leaning to try to do the smd myself, since I think I'll need the skill at some point anyway. And I think it would work better with the antennae constraints anyway.

    Working on the schematic: I'll (gratefully) upload an image by hand. I just hope no one laughs too hard = ).

    So I subscribed to the thread - I hope that lets me get updates.
    Last edited: Nov 7, 2013
  15. John P

    John P Senior Member

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    I don't understand what the connection is between Sparkfun and Gold Phoenix, but BatchPCB no longer exists as of May 2013. If you look for it, Sparkfun will refer you to this site:

    http://oshpark.com/

    and what they say is,
    "$5 per square inch for three copies of your design. For example, a 2 square inch board would cost $10 and you’d get three copies of your board."
  16. elec_mech

    elec_mech Senior Member

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    I think you meant barebonespcb.com which appears to be under Advanced Circuits.

    Sparkfun used to own BatchPCB, not Goldphoenix, but since then sold it to OSH Park. OSH Park charges $5 per square inch for a 2-layer board, but you get three boards for the price, so not too bad. $10 for a 4-layer board, again for three boards. Not sure if that includes shipping or not.

    What are the dimensions of your board, how may layers do you need, and how many do you intend to make?
  17. DerStrom8

    DerStrom8 Well-Known Member

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    Yes there is, and it still bugs me that it is not the default. Click on the "quick links" button up near the top (under your name), and under the heading "User Control Panel" select "Edit Options". On the new page, scroll down to the box labeled "Messaging & Notification". The second box inside it has a dropdown menu where you can select "Instant Email Notification". This should tell the site to send you an email every time a thread you've participated in gets a new response.

    Matt
  18. SgtWookie

    SgtWookie Expert

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    There's an easy way to get notified when there are replies to a thread: At the top of the thread you wish to get notified in, you will see on the menu bar a "Thread tools" option with a down-arrow to the right of it. Click that, and then select "Subscribe to thread" on the bottom of the list. Then select whether you want to be notified via E-mail or not.

    I would NOT want to be notified via E-mail by default, as the amount of E-mail I would get would be more insane than it already is.
  19. DerStrom8

    DerStrom8 Well-Known Member

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    Hmm, I did not realize it gave you the notification type select when you subscribed to the thread.
  20. donpetru

    donpetru Active Member

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    Click here.
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