made my first PCB, doesn't work

Discussion in 'General Electronics Chat' started by kam hagh, Nov 14, 2015.

  1. kam hagh

    Thread Starter Member

    Nov 7, 2015
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    Hi, I just finished my first pcb, Its a attiny board with a regulator a transistor and a connection to my sensor and motor (just wire pads)

    but, When i plug it in, The led does turn on, however the programmer gives no respond when i connect it to my circuit's ISP! (It has an ATtiny13a, which i have a dip version in my breadboard and it works great!)

    the connections sound fine to my with eye! I etched two of my tracks which i fixed with an led wire(multimeter reads 0ohms when i connect them! so it works) and i tried every single pin of my attiny with another and none of them give anything less then 10MOhm, and read 2ohms-0ohms to my isp connections(OFC checking each pin with the one it's supposed to connect to, MOSI to MOSI etc)

    here's a picture of my circuit! both eagle schematic and physical!

    [​IMG]
    20151113_125758.jpg

    EDIT: fixed the huge image and used the thumbnail instead! sorry!

    and i draw those smiley faces and the line around it when i was bored waiting for something :D they're not connected to anything!
     
  2. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    Your schematic is still unreadable. Blow up the schematic and take a screen capture of just that section. Or better print to a pdf. We don't need to see all that white space and your task bar.
     
  3. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    And what have you done to troubleshoot the issue? Do you at least have power?
     
  4. GopherT

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    Nov 23, 2012
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    Use the "Upload a File" button at the bottom of the text-entry box (next to the POST Reply button).
     
  5. spinnaker

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    Oct 29, 2009
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    Do you at least know how to check voltage? You are not going to get very far in your hobby if you don't know how to do some basic troubleshooting.
     
  6. kam hagh

    Thread Starter Member

    Nov 7, 2015
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    Yeah! OFC! if by checking voltage you mean just using multi meter like i do with batteries, I'm not that terrible :) where should i check voltage? And it is a hobby now but I'm planning on becoming an electric engineer or something close!
     
  7. dl324

    Distinguished Member

    Mar 30, 2015
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    Did you look at the PDF before posting? It's printed mirror image and not worth the bother to try to read. Also, cut out most of the white space next time; we don't need to see the coordinate rulers for such a simple circuit.
     
  8. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    The schematic is mirrored, I mirrored it back:

    kam_hagh_schematic.jpg


    I also looked at the PCB drawing. There are some spots that can lead to possible shorts:

    kam_hagh__PCB_possible_places_for_shorts.png

    And tried to draw some alternative routes for the traces (I do not have any PCB drawing tools here, so I did it in Kolourpaint):

    kam_hagh__PCB_alternate_routing_to_avoid_shorts.png

    Bertus
     
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  9. kam hagh

    Thread Starter Member

    Nov 7, 2015
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    Woops, sorry :( I was in a rush to go and study!

    I moved it to a PDF and removed the frame, looks readable to me now :)
     
    Last edited: Nov 15, 2015
  10. kam hagh

    Thread Starter Member

    Nov 7, 2015
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    Thanks a lot :) I did check the traces you mentioned, they all look good to both my eyes and my multi meter! My multimeter read 5kOhms for the trace near the regulator, the other two didn't need a multimeter, but i did and it was not a short circuit (I don't remember the value) And i did change the trace near the headers a bit (simply dragged them away) but sounds like i forgot to save it!
     
  11. dl324

    Distinguished Member

    Mar 30, 2015
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    As Bertus pointed out, you made your PCB layout more challenging than necessary. When I layout boards, I try to minimize the number of shorting opportunities.
     
  12. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    How many times do I need to ask before you will give an answer?

    Have you confirmed that your regulator is working? Do you have 5V out?
     
  13. kam hagh

    Thread Starter Member

    Nov 7, 2015
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    Yeah, it was my first layout :) I was also super exited!
    Maybe I'll print another better version of this, possibly with a bottom layer, I accidentally bought single layer PCB :S

    BTW, is that possible that I fried my chip? I should also mention that i dropped a tiny bit of solder into top of my AtTiny when I was done soldering, I simply just used my nail to remove it! Also i had to use soldering wick for a small bridge, is that possible that i burned it?
     
  14. kam hagh

    Thread Starter Member

    Nov 7, 2015
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    Yeah, The LED does turn of with the brightness i was expecting it to!
     
  15. kam hagh

    Thread Starter Member

    Nov 7, 2015
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    No wait its reading 3.6, weird, let me check something!
     
  16. spinnaker

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    Oct 29, 2009
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    Agreed. For such a simple circuit the layout is why too complicated. I just designed a PCB with 7 times more mcu pins and lots more components. I did not require on jumber on a single sided board. And I don't have a lot of experience with PCB design,

    Plus SMD is the wrong way to go for a newbie. You probably fried your mcu soldering it to the board. You also have a greater chance for solder bridges.
     
  17. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    So your eye can convert light intensity to voltage level? You are pretty amazing.

    Measure the voltage! And measure it at the mcu if you can.
     
  18. spinnaker

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    Oct 29, 2009
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    Yep.
     
  19. kam hagh

    Thread Starter Member

    Nov 7, 2015
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    I had soldered before, just pth( when i was a kid, with only 50% sucsses rate, ehm.... i did this to avoid drilling and to save space :) ) maybe i'll make my next one PTH! I also saw tons of SMD Soldering video i had to try it!

    maybe i'll desolder the IC and try it on a breakout board :? I'll first replace the Regulator! and try it on a breadboard
     
  20. kam hagh

    Thread Starter Member

    Nov 7, 2015
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    lol :) I thought it would be obvious! I did try with the bare 5v from arduino and its the same level of brightness! I'll never trust my eyes again!
     
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