Could use some help understanding values output from SparkFun Sound Detector

Sensors Sound & Audio
1

I’ve purchased a SparkFun Sound Detector (SEN-12642) and have it hooked up on a breadboard connected to a Raspberry Pi, with an MCP3008 ADC in circuit. I’m not an electrical or acoustical engineer, and need some help understanding the outputs from the AUDIO and ENVELOPE pins. The Java code I’m running reacts to the GATE pin going high and then reads both the AUDIO and ENVELOPE pins once per second until GATE goes low. Actually, I’m reading CH0 and CH1 on the MCP3008, which are the analog-to-digital outputs from AUDIO and ENVELOPE.

What I’m having difficulty understanding is what these values mean in terms of decibels. For example, with a straw I blow air across the microphone on the SparkFun board, and I see a stream of values from GATE and ENVELOPE. These values look like AUDIO=819.0, ENVELOPE=71.0, or AUDIO=1023.0, ENVELOPE=496.0, and so on. Could you provide any guidance on how to interpret these voltage values, and convert them to decibels? What is the full range of these values?

Thanks

2

Hi dclark,

This is a pretty tricky question since the outputs from the Sound Detector are really only in analog voltages. In order to equate them to a decibel level for sound, you would need to send a known decibel value to the Sound Detector and monitor the output. I would recommend reading [this comment chain on the product page with the engineer who designed the boards. That may help point you in the right direction for getting the data you want from the Sound Detector. Byron’s posts throughout those comments and the [Hookup Guide comments may also give you some more advice on how to proceed with this project.

I hope this helps. Let us know if you have any other questions and we would be happy to help as much as we can.](Discuss Tutorial: Sound Detector Hookup Guide - SparkFun Learn)](SparkFun Sound Detector - SEN-12642 - SparkFun Electronics)