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Smart Thermostat Graduation Project Final Check

Former Member

Hello everyone! I’m Enes and am hoping some of you folks may help me. I have this project for my graduation and I just wanted to be 100% sure before sending it to China for manufacturing - its my first time with PCBs O_O. It takes 3 weeks to arrive my country therefore I don’t have time to test it, I only got one shot. My prototype works perfectly on breadboard. This is the dropbox link to my BRD files and some screenshot for you guys to check it real quick: https://www.dropbox.com/sh/05sbwndrdl5tqql/AADXK4_4RyO7QGvu2Xw_t1Hka?dl=0

 

I have few questions below, and I really do appreciate if you download them and control it.

 

1- Transmission traces between FT232 and Atmega328 are not short traces. Are these traces going to cause any trouble?

2- Did I place the decoupling capacitors correctly in my layout?

3- Is 16mil drill size too small for manufacturing?

4- Do I need to add a diode between LM3940 and ESP8266-1 ?

 

Thanks a lot and have a great forum.

  • 0

    Hi Enes,

     

    I've had a quick look and I have a couple of comments. Running ratsnest shows there are 3 remaining air wires:

     

    • Signal D8 at the pin of ESP-01
    • Signal D9 at R1. This appears to be a schematic error. You have named the nets both sides of R1 as D9. Naming nets the same connects them together. If you didn't know this then I suggest you go through your design with a fine tooth comb in case you did these elsewhere.
    • Signal COM between SW1 and C2. Your COM polygon has got a split in it because some traces are causing it to not be able to get to the section that connects to C2.

     

    Edip Enes Cakir wrote:

     

    1- Transmission traces between FT232 and Atmega328 are not short traces. Are these traces going to cause any trouble?

    They aren't the longest traces I have seen and you have got series termination resistors which will help. Looking at your TX trace when it goes from RP1C to the FT232 though it looks like it does an unnecessarily long route. I can see at least two other more direct routes it could take.

     

    Edip Enes Cakir wrote:

     

     

    2- Did I place the decoupling capacitors correctly in my layout?

    The decoupling caps you have which I have looked at are ok but just from my quick glance I can see you have missed the decoupler from U2 (FT2332) on the VCC pin. It's not in the schematic and hence there is no decoupling for this part in the board.

     

    Edip Enes Cakir wrote:

     

    3- Is 16mil drill size too small for manufacturing?

    Not for any of the manufacturers I use but you would need to check with yours. If they have an EAGLE DRC file that they supply and you have run the DRC against this then if it doesn't give an error it should be ok. If in doubt ask the PCB manufacturer what their minimum drill sizes are.

     

    Edip Enes Cakir wrote:

     

    4- Do I need to add a diode between LM3940 and ESP8266-1 ?

    Why do you think you might? You'll need to be able to answer this yourself for your project thesis and as this is relating to your design and not EAGLE I'll refrain from looking at this one myself ;-)

     

    Best Regards,

     

    Rachael

     

    P.S. Run ERC and DRC and analyze and fix any errors!