My pcb did not work and i don't know why

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4

why do you have a separate power input not connected to the arduino 5V?

5

I think you can get the help you need if you are willing to put in the effort to provide more information.

  1. For the barrel connector power, is it set to positive or negative pin polarity?
  2. Can you upload the schematic symbol files that you used? U1, U2, and U3 are absolutely required to have any chance of knowing for certain where the problems are.
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I would start with the basics:

  1. Verify the connectors are not reversed. i.e. are the connected to the correct part of your shield circuit?

  2. On an empty board (i.e. no components) apply 5V power and verify it goes where you think it should.

  3. On your schematic, it looks like your power and ground are connected just below the barrel jack (on your schematic)

Baby steps. Don’t try to troubleshoot everything at once. You could do it a number of ways but one way is to take a blank board, Add the connectors but no other components. Using a volt meter verify your connections are what you expect.

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I’d like to say - you are very brave as you start your electronic adventure from something like that. I don’t know what arduino shield means. For me shield is a piece of metal closing the PCB inside it but it looks that here shield means something different.
I have started (many years ago) with simple external antenna + LC + diode + headphones to receive AM radio station.
Prepare yourself that at the beginning of electronic hobby most of the time you’re in a state of “why the hell isn’t that circuit working”. And the more such problems you solve yourself the more you learn.

The more problems will be solved for you by anyone else the less you will learn. If someone points you “here is the bug” and explains you why then it at once seems being so obvious that then you fast forgot it. If you spend hours searching a bug then when you at the end find it you will remember why it was wrong forever.
It is good for your mental health if you do not assume that shortly as soon as you design a circuit it will work well immediately.
Wish you everything good in your adventure with electronic.

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It’s just a fancy marketing name for an add-on piggyback board you connect to your Arduino host.

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You can say that a shield is like a cape but for arduino …

…what is cape? think about it like a hat but for beaglebone …

you don’t know hat? it is like a wing but for the raspberry …

… i could continue this a couple of times more I believe :joy:

As explained by @fred4u all of them are expansion boards meant to be fitted on top of the board with the “brains” (microprocessor/microcontroller).

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What is the exact BOM ? If reset is not working I suspect the pinouts of the switch do not align with the part you ordered

Also looking at the PCB file, its 4layers but the inner 2 are not used

11

No… I do not have a multimeter…

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This is a mistake. Because the original analog circuit had a barrel jack, stupidly i sticked to that

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Thank you…

  1. Hmmm i don’t know what you mean. The middle pin is Vcc and the other two external ones are GND
  2. What extension do these files have? I cannot seem to find them. But i found my custom symbol library files, they are {bck, dcm, lib} files. Are these the ones?

EDIT: I uploaded everything i have for this project in a zip file. Please look at the original question.
Thank you very much!

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  1. Yes, for sure they are correct.
  2. I am not sure what exactly you mean with this…
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Thank you for your kind words, but its a fun learning experience when you work for you hobby.
But if you are tight on deadlines and you just want to deliver your work and it does not work - at least the Hardware part, then it’s not fun.
The biggest problem is i dpn’t know what’s to blame, as everything looks good, and i don’t know how to debug this thing.

16

get a multimeter would be a good start…

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Thank you…

Hmmm i don’t know what you mean. The middle pin is Vcc and the other two external ones are GND

Barrel jacks are available in center pin positive and center pin negative. If your barrel jack polarity was reversed it could cause problems. As @halachal reccomends, get a multimeter!

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Never, and I mean NEVER start a (commercial, or payed) project with a tool that you are not familiar with.
Did you use a kind of autorouter?

19

@nick,

You will have to get a multimeter. You do not need an expensive one as precision is not warranted here.

Amazon has meters from $10 and up. I would suggest something no lower than $20, only for the expected added reliability.

John

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I think you might be looking at the whole board at once and find it overwhelming. As I suggested above, you start with simple things like is the power and ground connected the way you think it should (by your schematic. For instance; find the ground pin on your connector, then with the ohmmeter you will need to get measure from the connector to every component pad you have connected to ground. Then do the same with +V
Then make sure the +V is not connected to ground.
Move on to the reset and do the same.

You started with an advanced project. Which is fine but now you have to slow down and go in baby steps.

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I was playing with electronic for long time and build even complicated devices like device for setting the speed of electronic watches (receiver of very weak 32768Hz signal, 1MHz thermostatic generator (I build one from discrete elements + styrofoam) and several TTL counters). Each time I had a problem with something not working I dreamed of oscilloscope till I have build one myself. Nowadays it is much simpler - you can buy oscilloscope relatively cheap.
If you plan to do anything more with electronic the first ‘must have’ is oscilloscope.
You can of course try help yourself with multimeter as others suggest and in many cases it could be enough. But generally nothing can replace an oscilloscope.

I don’t like tracks at your PCB being 5 mils wide. I use 10 mils and in some places 8 mils. If I had THT elements with such big pads I would probably get out of pad with 20 (30) mils track and than change to 10 mils (just to have a solid track at the place where you solder).
You can check (with multimeter) if everything what is expected to be connected is connected (to check if any track isn’t broken) then you should understand your circuit so you should know what voltage (what signal if tested by oscilloscope) should be at each point and check if it is there.

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All I am asking is that you are certain that the cable providing power is configured to have a positive tip polarity; many tips can be swapped to make them negative.

Next up, I think you have a real mess on your hands. I am unable to read the intent of the circuit from your schematic.

diplwmatikh.sch (30.0 KB)

To start, look at the changes I made by removing many of the ground wires and replacing them with the GND symbol. You should continue to remove all the ground wires and replace them with the GND symbol.

Next, tell me what your intent was with P6 pins 3,4, and 5. Are these pins to be set as Input or Output?

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Just took a quick peek at the board. Unless I am mistaken, your traces (all of them) are only 5 mils thick. You might find that the board did not etch properly or that some tracks might be broken.

Your ground pour is connected to the ground pins of the arduino by a thin sliver of a track (5mil). You might find the you get issues if you try to power the board from the top DC jack.

While probably not neccessary, you did not connect the ground pin of header P5 (The ground next to the AREF pin)

Is the arduino going to be powered by a separate supply than the DC jack on the shield? You have not connected any power pins on header P2 to the supply on your board. So the arduino would have to be powered by a second supply (Which may have its own issues, reverse feeding from IO pins etc)

EDIT: I cannot see from the picture but make sure the metal solder joints of resistor RDiv1 are not touching the metal case of the USB jack on the arduino when you push the hat onto the arduino board.

EDIT: Not sure if I understand the circuit but it appears you are attempting to mux 1 of 8 sensor inputs into an opamp circuit. The arduino selects the “channel” and reads back the result from the opamps? Would need the datasheet of the sensor to understand more.

EDIT: What is the intended purpose of the 4 x 100p capacitors? Noise filtering?

EDIT: On a side note. You have a push-pull (totem-pole) output opamp driving one of the arduino I/O lines. If there is a bug in your code, you could potentially drive an output with an output and damage either your opamp, arduino or both. Consider adding a small resistor in the line to prevent damage if this does occur.

EDIT: Your 100n deoupling capacitors must be as close to the chip they are decoupling as possible. The caps on the board are miles away.

EDIT: It can happen, check that the chips have been soldered the correct way around and make sure the pins are not bridged/shorted with solder.

EDIT: Can you post some more pictures of the actual board. The board does not look like it is seated properly on the Mega, the pins of the header are exposed.