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kittengineering / Omgevingsmonitor_Software

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Sound level in a quiet room stays at 65 dBc #5

Open ademu-nl opened 5 days ago

ademu-nl commented 5 days ago

Most gadget data seems normal but the sound level in a quiet room always stays at 65 dBc. The dB LED seem to respond to loud sounds normally. Quiet: Phone 30 dB Gadget 65 dBc Music: Phone 55-60 dB Gadget 68 dBc Phone 58 dB Gadget 79 dBc (30 minutes later - is the response this slow? What is the dBc offset to dB(A)?)

FransKITTnl commented 3 days ago

It is possible there is still some bug in the firmware with respect to calculating the correct dBc values.

The code is found in the file microphone.c and the generated file i2s.c for the I2S settings that are used.

The relevant data-sheets can be found at: wiki: Datasheets

tjallingk commented 2 days ago

im currently looking into this it seems to be a variation in microphones i guess i found using dBValue = 20.0f * log10(rms) +106.0; in microphone.c to be somewhat okey by default it is +120 but i cant really get where that value is coming from. i also found quite a lot of interference or something in the output data like 3-5db fluctuations.