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My first Eagle schematic and board

Discussion in 'Circuit Simulation & PCB Design' started by antknee, Jun 20, 2010.

  1. PCBWING

    PCBWING New Member

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    The version more compact than the first.
     
  2. lilimike

    lilimike Member

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    I would be curious to know what you are using for IC2, I don't have too much experience but all of the dual op-amps I have used where the inputs were on pins 2 and 3 had the output on pin 1 and also, unused inputs had to be tied to negative supply.

    Mike
     
    Last edited: Jun 22, 2010
  3. antknee

    antknee New Member

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    You're ahead of me. I had the wrong pins on IC2. Edeca made me think about it and when I checked I thought omg I nearly chucked £30 down the pan. The intention was to get it made and see what the mistakes were but that would have been something that couldn't be debugged. I've had a look around to see if I could find a library containing the chip (TCA0372) but I can't find it, so I'm currently reworking with just the package - DIL8 - rather than the chip itself.

    That was a good spot! Thanks for the input.
     
  4. dave

    Dave New Member

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  5. vne147

    vne147 Member

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    The more boards you make will almost certainly need to make a custom part eventualy. I mean this is your first board and you already don't have all the parts you need. I would recommend learning how to make your own parts now. It's not difficult and could save you a lot of headache. There are loads of tutorials out there. You should be able to find one that's decent.

    Google - eagle tutorial make a part
     
  6. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    I am not criticizing here but rather providing pointers that will simplify and the routing and make the board easier to use.

    R4 looks to be a variable resistor. I would rotate it so the adjusting screw faced the edge of the board. If you run the trace going to pin 1 under R5 you can do it without running traces between the pins.

    I am thinking the routing for IC1 is more complex then it would need to be

    In some cases you can use resistors to bridge traces.
    For example if you move R8 directly below and in line with R9 you can eliminate the need to run the trace between IC1 pins 7 and 8.
    IC1 pin 6 (and 3). You have a right angle bend just prior to the pad. This is bad because it reduces the clearance between it and pad 5.

    I would try rotating IC1 90 or 270 degrees to see if it could be routed easier.
     
    Last edited: Jun 22, 2010
  7. antknee

    antknee New Member

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    I fixed the pins on IC3 and will be very careful to use the right chip/package in future. I rounded off the 90 degree junctions. I added two pots to adjust the voltage across the 555. This meant no matter how I tried I could no longer get everything onto one layer so I had to use two. I tried making the circuit smarter by putting components around the 555 and rotating to help the routing. I might have a go at making my own components for the next build.

    I think it is ok..? I'm going to check it over the next few days with regard to the circuit I have on the stripboard. Thanks for the comments.

    Antknee.

    [​IMG]
     

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  8. edeca

    edeca Active Member

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  9. antknee

    antknee New Member

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    The breadboard supply is impressive, everything sits just right. Credit. I'd say that sort of layout was something to be aimed for on every build.

    I have fixed the T pieces. The via near IC1 is a mistake I hadn't noticed, I was putting vias in the ground plane for my dual supply and must have clicked by accident.

    Thanks.

    Antknee.
     
  10. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    I do not know if you are having this board made or etching it yourself. If you are going to have it made ignore this post.

    If you etch it yourself you will not be able to solder under chips (top layer) if you use any sockets other then machine tool. The same it true for parts like the variable resistors and possibly the caps.
     
  11. antknee

    antknee New Member

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    I'm going to use this company:

    Quick information - PCB-POOL.COM

    They were recommended to me a while back and it is around £30/$50 for 1dm/3inches. I should get 3 boards. I thought about etching it myself but it would cost me around that much in kit and there would be the limitations you've noted. I'm tempted but it is a challenge for another time. Thanks. Antknee.
     
  12. antknee

    antknee New Member

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    I'm going to order the board, there are a few terms that I'm not familiar such as soldermask, silkscreen and HAL. What do these mean? I have defaulted to answering no. It will be £38 ($55) + delivery.

    Thanks.

    [​IMG]
     

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  13. edeca

    edeca Active Member

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    Don't miss the little question mark, which explains these terms.

    A silkscreen is the (usually) white printing on a board which indicates where components go. It can be quite useful for production boards, but you could live without it for a prototype.

    The soldermask is a layer applied to the whole board to make soldering easier. It covers all metal except for the pads and other parts which will need soldering. This makes surface mount parts a breeze (even in a frying pan) and also helps through-hole soldering too. But like the silkscreen you can probably live without it for a prototype board that only uses through-hole.
     
  14. antknee

    antknee New Member

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    It has been ordered, delivery was a bit more than I'd expected £7 ($11), I will watch out for that in future. The silkscreen info link was blank and the explanation of soldermask a lot less intuitive than yours :)

    Thanks for all the comments in this post, I just have to wait and cross my fingers now.

    Antknee.
     
  15. edeca

    edeca Active Member

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    Good luck! I've never used that company before so I'd be interested to know how it comes out.

    It's a really exciting process, great when it lands on your doorstep. Be prepared to fix errors though, I've made plenty over the last few boards I've manufactured.
     
  16. lilimike

    lilimike Member

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    Antknee,

    For the next time I would possibly suggest this place, I have not tried them out yet but I am planning to on my next board, it looks like it is the cheapest place I could find so far!

    $5/in² for 3 copies, no setup fee, shipping included (9 days) if this is all true and the boards come out descent, they will make lots of money with me!

    Mike
     
  17. PCBWING

    PCBWING New Member

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    With us, you can all choose yes,More economical!

    [​IMG]
     

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    Last edited: Jun 23, 2010
  18. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    The cost of getting a PCB made has come down a lot. I might not bother with DIY if I was not already doing it. I expect I will still make the first rev myself but past that I will be using a board house.

    Times are changing.
     
  19. PCBWING

    PCBWING New Member

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    welcome to try for the next time from us. Just make a comparison to see which one is more suitable.

    [​IMG]
     

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  20. PCBWING

    PCBWING New Member

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    10in² less is profitable.
     
  21. lilimike

    lilimike Member

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    yes that is for sure, I was referring to a small prototype in a quantity of no more than 3.
    Actually I was wondering how these people can manage to get this cheap to put together a bunch of PCBs and send them to a Fab house like yours!

    Why can't a Fab house do the same directly?
    By the way you have good prices, when I get into quantities you will see me drop by.

    Mike
     
    Last edited: Jun 23, 2010

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