Infrasound recordings of landing airplanes at Stuttgart Airport (EDDS). Vertical distance roughly 3000 meters. Most likely coming from extended landing flaps.
What is this thing?
This is an extremely sensitive infrasound microphone based on the differential pressure sensor Sensirion SDP600-25Pa and an ESP32 microcontroller. It works up to a sampling rate of 100Hz (=50hz usable range) and has a 13 Bit resolution.
How does this thing work?
- It connects to a Wifi accesspoint
- Initializes the SDP600-25Pa sensor
- Blasts out raw uint16_t measurement samples and their NTP synchronized timestamps as soon as you connect to the TCP port 1234
How to get this thing running?
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Modifiy the wifi.c to connect it to your local accesspoint
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Compile it using VisualStudioCode and the ESP-IDF plugin
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Use record-samples.py to save the measured samples to a file (e.q. examples.txt)
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Use the show_* scripts to visualize them
Hardware setup
Pin Configuration
Pin 21: SDA
Pin 22: SCL
Example Box
One Port of the differential sensor is open to sense the signal.
The second port is connected to a small plastic bottle which has an extremely small hole. This path very slowly follows the environmental pressure - much slower than the "high frequency" input signal. We notch out the DC part of the signal as its difference will be zero.
Limitations
The I2C clock stretching capability of the ESP32 is limited.
The highest resolution you can choose is 13 Bit. Everything higher will cause timeouts.
License
GPLv3