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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")
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