I am using the dfMiniPlayer module with DAC enabled. When I connect my headphones to the DAC output, or a speaker to the speaker output I hear a static sound and a clicking in the background. It gets worse at higher volumes. I have the TX and RX connected to my nano via a 1k resistor and am powering the dfPlayer externally. I am, however, using the busy pin connected to the Arduino, but disconnecting it during playback doesn't change the quality of sound.
I found a video on YouTube where the guy says to connect the TX and RX via 1K resistor and then a 2K resistor to ground, but when I do this the chip doesn't communicate well with the Arduino (delayed reaction if it works at all).
bradgentry926:
I am using the dfMiniPlayer module with DAC enabled. When I connect my headphones to the DAC output, or a speaker to the speaker output I hear a static sound and a clicking in the background. It gets worse at higher volumes. I have the TX and RX connected to my nano via a 1k resistor and am powering the dfPlayer externally. I am, however, using the busy pin connected to the Arduino, but disconnecting it during playback doesn't change the quality of sound.
Try using a stable power supply, and add some bypass caps. You're probably getting digital noise from the Arduino. Also, USB power is known to be quite noisy. You could try to use a separate power supply for the DAC and the Arduino. If you're using a switch-mode power supply, try a linear one.
bradgentry926:
I found a video on YouTube where the guy says to connect the TX and RX via 1K resistor and then a 2K resistor to ground, but when I do this the chip doesn't communicate well with the Arduino (delayed reaction if it works at all).
That's for a completely different reason: the DAC is probably 3.3V, and the Arduino outputs 5V. You should use a level shifter on the Arduino's TX pin, or a voltage divider, like in the video.
bradgentry926:
How would I go about adding the caps, and what caps would you recommend?
In parallel to the DAC, across the 5V lines, as close to the DAC as possible. Try different caps, see what works best. Start with 100nF, and maybe add a 10µF as well. Just take a whole bunch of different capacitors, put them in one by one, see which one reduces the noise, also try combining different values.
bradgentry926:
Also, would a ground loop isolator help any?
Probably not, since the problem persists, even with headphones.
Did you try a different power supply, like I suggested?
bradgentry926:
What resistor set-up should I use? As I said, the 1k + 2k makes the chip non-responsive.
If you would have googled it, you would have found plenty of schematics online. You probably would also have found out that the dfMiniPlayer can operate at 5V, so it doesn't need any level shifting. For an unknown reason, they do add a 1K series resistor, however:
PieterP:
In parallel to the DAC, across the 5V lines, as close to the DAC as possible. Try different caps, see what works best. Start with 100nF, and maybe add a 10µF as well. Just take a whole bunch of different capacitors, put them in one by one, see which one reduces the noise, also try combining different values.
So I would run the caps from the ground of the DAC to the L and R channels? I have never done this before, so I'm not following your description.
PieterP:
Did you try a different power supply, like I suggested?
Yes, but it still remained. Also, when the project is in use the Nano and the player will be powered by the same battery. Having 2 supplies there is not possible.
PieterP:
If you would have googled it, you would have found plenty of schematics online. You probably would also have found out that the dfMiniPlayer can operate at 5V, so it doesn't need any level shifting. For an unknown reason, they do add a 1K series resistor, however:
Pieter
I did Google it, which is why I had it wired up the way that I did, and also why I tried the 2K resistors to ground as found in a Youtube video.