In the second image (I got it from the tutorial where I also got the first image), I can see a capacitor (rounded in blue) that maybe solves the problem, but I don't know why it doesn't appear on the diagram.
Grumpy_Mike:
First off you are using the wrong work. A sketch is the name for the Arduino’s program.
What you have here are a physical layout diagram and a photograph.
The capacitor is across the power supply and acts as power supply decoupling, it may well stabilise things.
Have you measured any voltages for the power to each unit in the two cases of powering your project?
Thanks for your reply. I already changed sketch -> diagram, sorry.
The project has to work with the power connected to the Micro USB connector, I have connected this Micro USB connector to a 5V power unit, but like I wrote, it produces a weird sound on the MP3 module.
About the capacitor, I really don't know I where should I place it or which one to use to fix the problem, I'm not very expert on the subject.
I have added on the image the capacitor that I tested. I tested with 47uF, 100uF, 220uF, 330uF and 470uF but I got the same problem with everyone, I don't know if maybe I didn't connected it well.
Grumpy_Mike:
Have you measured any voltages for the power to each unit in the two cases of powering your project?
No. I don't have any tool to do it.
I have tested the following: instead of connecting the micro USB connector to the power, connecting to my computer thourgh USB (remember that the sound is good if I connect the arduino to my computer through USB) but it doesn't work! I don't know if that can give you a clue
Thank you for replying to my question, it is never good to hide things.
I don’t understand why you don’t buy a digital voltmeter. They cost less than an Arduino in a thrift store.
It will tell you what is wrong.
It could be that the power supplies you have tried need a pull down resistor on one or other of the data lines. This is often used the “tell” the power supply how much current it needs to supply and the power supply will adjust its voltage output accordingly. This could be why it appeared to work when you connect it to your computer.
What happens when you try and use the USB socket on the Nano with your power supply, will this work?
hes using a qc/fc charger that can put 9v to the usb port
i would make sure the usb +v is going to the vin on the arduino, and regulated 5v is connected to all modules so they are not overvolted
and add a small cap around 100uf to usb and +5v lines
20-40v 100uf for the usb +v
and 10v 100uf to arduino 5v output
(cap should be around double the max voltage, qc/fc can go upto 20v)
pick up a nice little multimeter for under $15
and the dso138 sillyscopes are good for 5v projects
the kits have alot of smd (small surface mount) components not for beginners to soldering
but assembled its under $40
