AudioMoth - Revision history

Bertrik Sikken: /* Suggested trigger extension */

2021-04-07T09:43:16Z

Suggested trigger extension

← Older revision		Revision as of 09:43, 7 April 2021
Line 53:		Line 53:
	Proposed algorithm:		Proposed algorithm:
	# Apply a high-pass filter at about 10 kHz, this needs not be super-sharp filter. Perhaps just a simple 1-pole IIR (easy to calculate).		# Apply a high-pass filter at about 10 kHz, this needs not be super-sharp filter. Perhaps just a simple 1-pole IIR (easy to calculate).
	# Calculate the energy in each millisecond by ~~adding~~ the squared amplitude of the high-pass filtered signal over this millisecond. Perhaps we can also just calculate variance here and forget about step 1).		# Calculate the energy in each millisecond by summing the squared amplitude of the high-pass filtered signal over this millisecond. Perhaps we can also just calculate variance here and forget about step 1).
	# Calculate a running average energy over several (say 500) of these milliseconds values.		# Calculate a running average energy over several (say 500) of these milliseconds values.
	# If the millisecond energy exceeds the average energy by a factor X (the sensitivity of the trigger), consider the trigger to be active.		# If the millisecond energy exceeds the average energy by a factor X (the sensitivity of the trigger) for a duration of Y consecutive milliseconds, consider the trigger to be active.

	=== Running the tools ===		=== Running the tools ===

Bertrik Sikken: /* Suggested trigger extension */

2021-04-07T09:28:18Z

Suggested trigger extension

← Older revision		Revision as of 09:28, 7 April 2021
Line 52:		Line 52:

	Proposed algorithm:		Proposed algorithm:
	1) Apply a high-pass filter at about 10 kHz, this needs not be super-sharp filter. Perhaps just a simple 1-pole IIR (easy to calculate).		# Apply a high-pass filter at about 10 kHz, this needs not be super-sharp filter. Perhaps just a simple 1-pole IIR (easy to calculate).
	2) Calculate the energy in each millisecond by adding the squared amplitude of the high-pass filtered signal over this millisecond. Perhaps we can also just calculate variance here and forget about step 1).		# Calculate the energy in each millisecond by adding the squared amplitude of the high-pass filtered signal over this millisecond. Perhaps we can also just calculate variance here and forget about step 1).
	3) Calculate a running average energy over several (say 500) of these milliseconds values.		# Calculate a running average energy over several (say 500) of these milliseconds values.
	4) If the millisecond energy exceeds the average energy by a factor X (the sensitivity of the trigger), consider the trigger to be active.		# If the millisecond energy exceeds the average energy by a factor X (the sensitivity of the trigger), consider the trigger to be active.

	=== Running the tools ===		=== Running the tools ===

Bertrik Sikken: /* Hardware */

2021-04-07T09:26:51Z

Hardware

← Older revision		Revision as of 09:26, 7 April 2021
Line 36:		Line 36:

	The processor is EFM32WG380F256, [https://www.silabs.com/mcu/32-bit/efm32-wonder-gecko/device.efm32wg380f256-qfp100 link]		The processor is EFM32WG380F256, [https://www.silabs.com/mcu/32-bit/efm32-wonder-gecko/device.efm32wg380f256-qfp100 link]

			Where is the schematic?

	== Software ==		== Software ==

Bertrik Sikken: /* Suggested trigger extension */

2020-04-14T12:21:27Z

Suggested trigger extension

← Older revision		Revision as of 12:21, 14 April 2020
Line 50:		Line 50:

	Proposed algorithm:		Proposed algorithm:
	* Apply a high-pass filter at about 10 kHz, this needs not be super-sharp filter. Perhaps just a simple 1-pole IIR (easy to calculate).		1) Apply a high-pass filter at about 10 kHz, this needs not be super-sharp filter. Perhaps just a simple 1-pole IIR (easy to calculate).
	* Calculate the energy in each millisecond by adding the squared amplitude of the high-pass filtered signal over this millisecond.		2) Calculate the energy in each millisecond by adding the squared amplitude of the high-pass filtered signal over this millisecond. Perhaps we can also just calculate variance here and forget about step 1).
	* Calculate a running average energy over several (say 500) of these milliseconds values.		3) Calculate a running average energy over several (say 500) of these milliseconds values.
	* If the millisecond energy exceeds the average energy by a factor X (the sensitivity of the trigger), consider the trigger to be active.		4) If the millisecond energy exceeds the average energy by a factor X (the sensitivity of the trigger), consider the trigger to be active.

	=== Running the tools ===		=== Running the tools ===

Bertrik Sikken at 09:47, 14 April 2020

2020-04-14T09:47:04Z

← Older revision		Revision as of 09:47, 14 April 2020
Line 39:		Line 39:
	== Software ==		== Software ==
	My fork on github: https://github.com/bertrik/AudioMoth-Project		My fork on github: https://github.com/bertrik/AudioMoth-Project

			=== Suggested trigger extension ===
			A bat specific trigger is desireable because this way we only get "interesting" files.

			The idea is that bat signals are, in general:
			* ultrasonic, frequency above 10 kHz
			* organised in short pulses, e.g. 8 pulses per second of 5 ms each for a pipistrelle
			Challenges:
			* crickets, sound is also at least partly ultrasonic, overlapping with the calls of some of the larger bats and with social bat calls in general

			Proposed algorithm:
			* Apply a high-pass filter at about 10 kHz, this needs not be super-sharp filter. Perhaps just a simple 1-pole IIR (easy to calculate).
			* Calculate the energy in each millisecond by adding the squared amplitude of the high-pass filtered signal over this millisecond.
			* Calculate a running average energy over several (say 500) of these milliseconds values.
			* If the millisecond energy exceeds the average energy by a factor X (the sensitivity of the trigger), consider the trigger to be active.

	=== Running the tools ===		=== Running the tools ===
	Running the tools (configuration tool, flash tool, etc) requires the --no-sandbox option (at least on my system), for example		Running the AudioMoth tools (configuration tool, flash tool, etc) requires the --no-sandbox option (at least on my system), for example
	./AudioMothConfigurationAppSetup1.2.5.AppImage --no-sandbox		./AudioMothConfigurationAppSetup1.2.5.AppImage --no-sandbox

	=== IDE for development ===		=== IDE for development ===
	A description of all ~~the~~ steps to get the firmware compiled is written here:		A description of all steps to get the firmware compiled is written here:
	https://github.com/OpenAcousticDevices/AudioMoth-Project/wiki/AudioMoth		https://github.com/OpenAcousticDevices/AudioMoth-Project/wiki/AudioMoth

Bertrik Sikken: /* IDE for development */

2020-04-08T20:16:34Z

IDE for development

← Older revision		Revision as of 20:16, 8 April 2020
Line 45:		Line 45:

	=== IDE for development ===		=== IDE for development ===
	A ~~brave attempt for~~ all the steps to get the firmware compiled ~~was~~ written here:		A description of all the steps to get the firmware compiled is written here:
	https://github.com/OpenAcousticDevices/AudioMoth-Project/wiki/AudioMoth		https://github.com/OpenAcousticDevices/AudioMoth-Project/wiki/AudioMoth

Bertrik Sikken: /* What */

2020-04-08T13:56:54Z

What

← Older revision		Revision as of 13:56, 8 April 2020
Line 13:		Line 13:
	Ideas:		Ideas:
	* general clean-up		* general clean-up
	** fix white space, remove many of the empty lines (earlier CR/LF mistake?)		** fix white space, remove many of the empty lines (earlier CR/LF mistake?), like these https://github.com/bertrik/AudioMoth-Firmware-Basic/blob/master/main.c#L154
	** fix sprintf statements		** fix sprintf statements, like these https://github.com/bertrik/AudioMoth-Firmware-Basic/blob/master/main.c#L167
	** fix complicated and non-portable casts (sensitive to endianness)		** fix complicated and non-portable casts (sensitive to endianness), like this https://github.com/bertrik/AudioMoth-Firmware-Basic/blob/master/main.c#L161
	* update tool-chain to newer version		* update tool-chain to newer version
	** update gcc		** update gcc

Bertrik Sikken: /* Hardware */

2020-04-08T13:02:48Z

Hardware

← Older revision		Revision as of 13:02, 8 April 2020
Line 31:		Line 31:

	The microphone is a [https://www.mouser.com/datasheet/2/218/-532499.pdf SPM0408LE5H].		The microphone is a [https://www.mouser.com/datasheet/2/218/-532499.pdf SPM0408LE5H].
	Can't find much about ~~it's~~ ultrasonic performance. The official graph shows a hint of resonance above 10k so it does have ultrasonic sensitivity.		Can't find much about its ultrasonic performance. The official graph shows a hint of resonance above 10k so it does have ultrasonic sensitivity.
	For frequencies higher than the resonance peak the response of a typical microphone drops off steeply with 6 dB/octave.		For frequencies higher than the resonance peak the response of a typical microphone drops off steeply with 6 dB/octave.
	I have been able to record some pipistrelle bats with it (40 - 50 kHz).		I have been able to record some pipistrelle bats with it (40 - 50 kHz).

Bertrik Sikken: /* Hardware */

2020-04-08T11:33:58Z

Hardware

← Older revision		Revision as of 11:33, 8 April 2020
Line 32:		Line 32:
	The microphone is a [https://www.mouser.com/datasheet/2/218/-532499.pdf SPM0408LE5H].		The microphone is a [https://www.mouser.com/datasheet/2/218/-532499.pdf SPM0408LE5H].
	Can't find much about it's ultrasonic performance. The official graph shows a hint of resonance above 10k so it does have ultrasonic sensitivity.		Can't find much about it's ultrasonic performance. The official graph shows a hint of resonance above 10k so it does have ultrasonic sensitivity.
	For frequencies higher than the resonance peak the response of a typical microphone drops of with 6 dB/octave.		For frequencies higher than the resonance peak the response of a typical microphone drops off steeply with 6 dB/octave.
	I have been able to record some pipistrelle bats with it (40 - 50 kHz).		I have been able to record some pipistrelle bats with it (40 - 50 kHz).

Bertrik Sikken: /* Hardware */

2020-04-08T11:33:16Z

Hardware

← Older revision		Revision as of 11:33, 8 April 2020
Line 30:		Line 30:
	See https://circuithub.com/projects/OpenAcoustics/AudioMoth		See https://circuithub.com/projects/OpenAcoustics/AudioMoth

	The microphone is ~~SPM0408LE5H,~~ [https://www.mouser.com/datasheet/2/218/-532499.pdf ~~datasheet~~].		The microphone is a [https://www.mouser.com/datasheet/2/218/-532499.pdf SPM0408LE5H].
	Can't find much about it's ultrasonic performance. The official graph shows a hint of resonance above 10k so it does have ultrasonic sensitivity.		Can't find much about it's ultrasonic performance. The official graph shows a hint of resonance above 10k so it does have ultrasonic sensitivity.
	For frequencies higher than the resonance peak the response of a typical microphone drops of with 6 dB/octave.		For frequencies higher than the resonance peak the response of a typical microphone drops of with 6 dB/octave.