PCB design advise needed

Discussion in 'The Projects Forum' started by yonubear, Jun 5, 2016.

  1. yonubear

    Thread Starter Member

    Jan 10, 2013
    73
    1
    hi all I am hoping someone has a moment to look at the pcb design for me I just want a second set of eyes to look at it before I start make it as this is the jurst board I have made so not sure if the design will work or not it is for an arduion nano if that matters I am attaching the schematic and the pcb with labels all the vias are for wires as I ended up in a few places I couldn't get back to the arduino pins with traces
    CEC_Electrical.png Untitled Sketch_pcb.jpg

    Thanks,
    Yonu
     
  2. dl324

    Distinguished Member

    Mar 30, 2015
    3,243
    620
    Your traces are a bit haphazard and you have a 90 degree bend which is generally discouraged unless absolutely unavoidable (it causes current crowding on the inside corner). If there's a possibility that you'll be reworking the board, enlarging the pads will make that easier. If you didn't mount the resistors vertically, you could avoid the jumpers; you appear to have plenty of space. I find it more aesthetically pleasing to layout components in some sort of grid.
     
  3. yonubear

    Thread Starter Member

    Jan 10, 2013
    73
    1
    Yeah I know they are a little haphazard.

    I originally started with the resistors laying flat but I could not seam to get everything on the board. Which is why I switched to vertical resistors and diodes. what is the trick to working with a PCB this size and getting everything in?
     
  4. dl324

    Distinguished Member

    Mar 30, 2015
    3,243
    620
    Thoughtful component placement, well drawn schematics, experience, practice, ...
     
  5. yonubear

    Thread Starter Member

    Jan 10, 2013
    73
    1
    makes since I am used to working from scratch on perf board I just figured for something this small a printed board would be easier back the the drawing board I suppose.

    Thanks,
    Yonu
     
  6. dl324

    Distinguished Member

    Mar 30, 2015
    3,243
    620
    Here's a 1.5"x2.0" board I did about 10 years ago

    upload_2016-6-5_8-39-9.png upload_2016-6-5_8-39-37.png upload_2016-6-5_8-39-57.png
     
  7. yonubear

    Thread Starter Member

    Jan 10, 2013
    73
    1
    all I can say is wow that looks good
     
  8. dl324

    Distinguished Member

    Mar 30, 2015
    3,243
    620
    Thanks. Note that I violated the rule about 90 degree bends at the bottom of the board. It was a conscious decision because using 45's would have removed clearance to the nearby pin. Since I etch my own boards, I try to reduce the "hard" areas. The trace in question only carries a couple mA, so current crowding isn't an issue.
     
  9. yonubear

    Thread Starter Member

    Jan 10, 2013
    73
    1
    I noticed that but I wasn't sure if that had been on purpose or not


    if you would have a look at this I decided to start over and was shocked how quick it came out compared to the last one the only problem I have is R4 which one side should be going to ground but I have got it land locked
    Untitled Sketch_new_pcb.jpg

    Thanks,
    Yonu
     
  10. ISB123

    Well-Known Member

    May 21, 2014
    1,239
    527
    You need a better PCB software.It could really change the tables.
     
  11. yonubear

    Thread Starter Member

    Jan 10, 2013
    73
    1
    I will play with some other programs but let me ask you from the jpg I just uploaded can you see any way with a single layer board to get R4 to ground without using a single wire?

    Thanks,
    Yonu
     
  12. dl324

    Distinguished Member

    Mar 30, 2015
    3,243
    620
    Move R4 next to R10, straddle the trace from R10 going east, and pick up ground from C4.
     
  13. dl324

    Distinguished Member

    Mar 30, 2015
    3,243
    620
    If you label the pins on your board, I'll give the layout a try when I have some time.

    In the meantime, you can make your board more aesthetically pleasing if you keep the components on a 0.1" grid and line them up. For example, R1, R3, R5, and D1 can be lined up.
     
  14. Lestraveled

    Well-Known Member

    May 19, 2014
    1,957
    1,215
    Here is an example of what Dennis is talking about.

    Triac Controller pcb.jpg
     
  15. dl324

    Distinguished Member

    Mar 30, 2015
    3,243
    620
    What program are you using? Does it show you a ratsnest (fly wires) when you're placing components?

    On your layout you have the two transistors about as far away from each other as possible; but, on the schematic, they're close. That's what I meant by topological (well drawn) schematics. A neat schematic should make it easier to create a compact PCB layout.
     
  16. thumb2

    Member

    Oct 4, 2015
    66
    4
    KiCad is free program for PCB design. Take a look at it. ;)
     
  17. yonubear

    Thread Starter Member

    Jan 10, 2013
    73
    1
    I am using fritzing as it is what I have used for perfboard layouts in the past. yes it shows ratsnest wires but I don't have the schematic entered in the program as I am working from the one provided with the code. The only reason I have the trasnsisters far apart was to make it easier to get all the traces in place
     
  18. yonubear

    Thread Starter Member

    Jan 10, 2013
    73
    1
    oh and I just saw the post about moving R4 I don't know why I didn't think about placing the resistor over the trace.

    Thanks,
    Yonu
     
  19. dl324

    Distinguished Member

    Mar 30, 2015
    3,243
    620
    Two of the I/O's are missing (I labeled the 4 you connected):
    upload_2016-6-5_14-21-46.png
    What are the dimensions of the board? Are the pins along the left/right edges 0.1" spacing? Are you trying to do a single sided board?
     
  20. yonubear

    Thread Starter Member

    Jan 10, 2013
    73
    1
    ok the pins on the right and left are 0.1" yes I am trying for single sided. The board is going to be 0.73" x 1.70" the same size as an arduino nano.

    I assume the 2 missing IOs you refer to are the cec_line and cec_gnd they ae the 2 marked vias as right not they are gonna be wires in the board that goto the 2 wires on the hdmi port.

    Thanks,
    Yonu
     
Loading...