44 lines
866 B
Python
44 lines
866 B
Python
import audiobusio
|
|
import board
|
|
import digitalio
|
|
import array
|
|
import time
|
|
import math
|
|
|
|
trigger = digitalio.DigitalInOut(board.D4)
|
|
trigger.switch_to_output(True)
|
|
|
|
|
|
def mean(values):
|
|
return sum(values) / len(values)
|
|
|
|
|
|
def normalized_rms(values):
|
|
minbuf = int(mean(values))
|
|
samples_sum = sum(float(sample - minbuf) * (sample - minbuf) for sample in values)
|
|
|
|
return math.sqrt(samples_sum / len(values))
|
|
|
|
|
|
# signed 16 bit
|
|
s16 = array.array("H", [0] * 10000)
|
|
|
|
pdm = audiobusio.PDMIn(clock_pin=board.D11, data_pin=board.D12, sample_rate=24000, bit_depth=16)
|
|
|
|
print("starting read")
|
|
trigger.value = False
|
|
count = pdm.record(s16, len(s16))
|
|
trigger.value = True
|
|
print("read done")
|
|
print("recorded {} samples".format(count))
|
|
for v in s16[:count]:
|
|
print(v)
|
|
|
|
|
|
magnitude = normalized_rms(s16)
|
|
print("magnitude", magnitude)
|
|
|
|
print("count", count)
|
|
|
|
print("done")
|