Audio output

[HMC123-puxel]

I am using the PyControl's (audio board and speaker but the tones are quite noisy (e.g., 5KHz sine wave). are there any settings to clear better the played tones? will using a better speaker (e.g., speaker help? what is the recommended speaker's impedance and what is the amp output power (to find alternative compatible speakers)?

Thanks!

[alustig3]

Hi @HMC123-puxel,

Here is a video of me testing a 5KHz sine wave using the audio board and speaker you mentioned (make sure to unmute when playing).

audio_board_test.mov

Are you getting similar results? If the noisiness you are referring to is present in my video, can you give more details about what you mean by it being quite noisy?

Otherwise, if the output I'm getting is suitable / what you want, I can potentially help troubleshoot.

I have modified the example/blinker.py task, adding a 5 KHz tone whenever blue led blinks:

# A simple state machine which flashes the blue LED on the pyboard on and off.
# Does not require any hardware except micropython board.

from pyControl.utility import *
from devices import *

blue_LED = Digital_output("B4")

## added audio stuff
board = Breakout_1_2() 
speaker = Audio_board(board.port_4) # Instantiate audio board on either port 3 or 4 of breakout v1.2

# States and events.

states = [
    "LED_on",
    "LED_off",
]

events = []

initial_state = "LED_off"

# State behaviour functions


def LED_on(event):
    if event == "entry":
        timed_goto_state("LED_off", 0.5 * second)
        blue_LED.on()
        speaker.sine(5000) # turn on 5KHz sine wave.
    elif event == "exit":
        blue_LED.off()
        speaker.off() # turn off tone


def LED_off(event):
    if event == "entry":
        timed_goto_state("LED_on", 0.5 * second)


# Run end behaviour


def run_end():  # Turn off hardware at end of run.
    blue_LED.off()
    speaker.off()

here are a couple of troubleshooting ideas:

• make sure you are powering the breakout board with a 12V power supply (not just a USB connection)
• make sure the audio board is plugged into either port 3 or port 4 (the audio board requires a port with a DAC output and a I2C interface for controlling the volume see docs)
• are the wired connections from the audio board to onto the speaker good?
• are the wired connections from the speaker onto audio board good?
• does the potentiometer (plastic blue knob) on the audio board seem to have good connections soldered well? Does pressing or adjusting the knob produce any glimpses of improvements to the noisiness?
• can you try using both port 3 and port 4 (remembering to update the task code) and see if perhaps one of the ports is damaged/the source of the problem
• do you have multiple audio boards and/or speakers that you could mix and match to see if the problem follows some particular hardware?

Best,
Andy