Hello, I control 12v RGB strip leds in my project. However, I am having a sound problem when Colors start to light up as seen in the Video. I fed the leds with a 12v 3A adapter, I do not have any problems when I feed the PAM8403 amplifier module separately with a mobile phone adapter (5v 2A), but I want to do this project with a single adapter.
I fed PAM8403 with Voltage Regulator didn't work, like this
I tried many ways, but none of them worked for me. How can I fix this problem?
You probably have not observed star-grounding in your layout, so that current to the LEDS is going through wires that handle audio signals. Wires and particularly breadboard
connections have resistance, so any current variations will generate voltages that pollute
the sound.
Thus you must arrange that such currents between the power source and LEDs do not flow
along any wires involved in the audio path - learn about star grounding where such
currents are kept to separate wires everywhere.
So should I gather the GND lines of all the parts in the circuit in a common place and connect them to the ground line of my 12V adapter. Did I get right? I'm new to Arduino sorry
Thank you, my english is a bit poor and i'm new to arduino so i am sorry. Thanks to this forum, I am trying to learn. I will search from the link you shared, I hope I can understand.
So should I gather the GND lines of all the parts in the circuit in a common place and connect them to the ground line of my 12V adapter. Did I get right?
Yes. The problem is PWM and digital clocks etc. create noise in the ground (0V reference) wiring and PCB traces. If you keep the noisy digital ground away from the sensitive audio ground, the digital noise won't "sneak" in to the audio.
One very basic thing you can try is putting a large electrolytic capacitor between +V and -V or ground, like, 47u or 100u. You can do that on the breadboard if you have the power supply plugged in to the long red and blue power buses.
Well it is a start but you also need ceramic capacitors with a value of 0.1uF to handle the high frequencies. You can further reduce the noise by using inductors in what is called a Pi filter, going from the power source to each separate component of the setup. You can see a diagram of this filter on my web page on this topic, it is the last diagram on the page. http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html
