I am building a knock sensor board based on a Teensy 3.6
I am utilising the onboard ADC and have a 4 pole MFB low pass @16Khz between the knock sensor and the ADC input.
The ADC is biased to 3.3v/2 with a ~0.5 amplifier output from the MFB because the sensor is ~6v at max output.
The FFT will be 256 bin(audio library) and I am wanting a window time of ~1ms to suit a 40Deg knock window at 6000rpm on a 6 cylinder engine.
The board is also an interface between the factory CAN bus and the aftermarket ECU. The factory CAN format can't be understood by the aftermarket ECU(Motec M800).
The aftermarket ECU sends a "high" trigger signal for the window time and when it goes "low" it expects the knock level(voltage 0-5v) on another input.
I will use the "low" time to measure the background noise level and subtract it from the "high" window to only send the signal that exceeds the background noise.
I have found how to change the ADC reference source away from the default to external/3.3v reference.
My main problem I am finding, is how to change the audio library away from the default 44.1Khz to something around 96Khz to get my desired time window.
Any help appreciated
I am utilising the onboard ADC and have a 4 pole MFB low pass @16Khz between the knock sensor and the ADC input.
The ADC is biased to 3.3v/2 with a ~0.5 amplifier output from the MFB because the sensor is ~6v at max output.
The FFT will be 256 bin(audio library) and I am wanting a window time of ~1ms to suit a 40Deg knock window at 6000rpm on a 6 cylinder engine.
The board is also an interface between the factory CAN bus and the aftermarket ECU. The factory CAN format can't be understood by the aftermarket ECU(Motec M800).
The aftermarket ECU sends a "high" trigger signal for the window time and when it goes "low" it expects the knock level(voltage 0-5v) on another input.
I will use the "low" time to measure the background noise level and subtract it from the "high" window to only send the signal that exceeds the background noise.
I have found how to change the ADC reference source away from the default to external/3.3v reference.
My main problem I am finding, is how to change the audio library away from the default 44.1Khz to something around 96Khz to get my desired time window.
Any help appreciated