Hi all,
First let me thank you all the hard efford you did with me on this.
Few months have past since I started this trhead and I finally managed to get my PCB with me. I have been waiting 3 weeks for few PCB, several projects, but the most difficult one was this one.
After soldering all the components and uploading the code to Arduino I tested up the project and sadly it doesn’t work.
Here is a picture of the current PCB:
As you can see in the image, I had run into several problems:
First, the 2.1 Barrel Jack connectors didn’t fit with the PCB footprint created with Frizting, the 2.1 Jack has flat pins instead of regular ones so It doenst fit in the holes (My bad, I should have printed the PCB and try each component). As I’ll Be 3d printing a case for this PCB I dont mind wiring it up directly from PSU to PCB like the picture is showing so this problem is not really a big deal for me.
Second, the rj45 Connectors were flipped, so I had to solder them on the opposite side of the PCB to make them match the current pinout running trought the rj45 cable to the MFRC522.
Those were the mistakes I found on the PCB creation, as you can see, nothing that I couldn’t deal with.
Now the actual problem is that the circuit is not working as intended. MFRC522 Readers are not starting properly, not even a firmware error, they are just not recognized by arduino on Startup.
Checked both GND and VCC pins on the MFRC522 Side, steady 3,3v read by a multimeter. So voltage is not the problem I guess.
Checked continuinity between PCB and the actual MFRC522 pin, everything was OK. (Ohmetter between pin D2 and SDA2(on the MFRC522 PIN) showed up 1Ohm resistor so I guess this is generated by the cable itself and the components. The same happens with SCK(pin 13), MISO(pin 11) and MOSI (pin 12). Reset pin(pin 8) also shows continuity aswell as GND and VCC.
I’m powering up this project with 3 Diffrent wallmart: 2 of them are 12v 2A and one of them (for a solenoid lock) 12v 3A. One of the 12v 2A PSU is connected directly to the MP1584EN voltage regulator with an ouput voltage of steady 5v, this is wired to Arduino 5v Pin and LM1117T voltage regulator (that supplies 3,3v to ESP8266 and the 4 MFRC522 readers). The second 12v 2A PSU is also wired to a second MP1584EN Voltage regulator, 5V out for powering up a led strip (Wich works perfectly).
What I found strange was the fact that if I plug the Arduino Nano to an USB port its 5v pin will feed the LM11117T regulator and it will also give me 3,3v to the ESP8266 and RFID readers, also I can read 4,3v on the MP1585EN output hooked up to the arduino 5v. I guess this makes sense since arduino is triying to feed the voltage regulator in the opposite direction.
I shall say that this project was already created on breadboard and it worked like a charm, with same rj45 connectors and cables, the whole point on moving to PCB was avoiding the noises generated by LOT of dupont cables running from BB to the MFRC522 readers. So I don’t really have a clue why this is not working at all.
The video I followed months ago when I started the project was this : https://www.youtube.com/watch?v=f_f_5cL0Pd0&ab_channel=PlayfulTechnology
Not taking the codification in count (which i Know it is well coded since It was working on BB) do you think the PCB wiring is correct?
Sorry for the big post, but i Tought it was a nice idea to give feedback about this project and also to give you more information regarding this problem which is driving me mad already.
Thanks in advance guys for your help. Attaching the PCB Fritzing project if you want to double check it.heimdallRunes.fzz (123.7 KB)
Edit: I forgot to mention that ATMEGA chip on the Arduino Nano is getting hotter than I expected.