Recent content by tschrama

There is no need for nanosecond resolution. The PPS from a GPS receiver will provide 10usec resolution for annabsolute time stamp. This is enough to triangulate the sound source with multiple mics. Any wheater proof mic with a wind ‘hat’ will do. But you will need a mic preamp and ADC and teensy...

pictures, or it didnt happen ;-)

If you put 5V on pin4 of the midi_in, does pin 6 of the opto go to 0V? If you put 0V on pin4 of the midi_in, does pin 6 of the opto go to 3.3V? If yes, then at least your opto does work. In that last photo, I still see a 10K from pin 5 to gnd. Pin5 should go directly to GND. pin7 goes , via...

If you put 5V on pin4 of the midi_in, does pin 6 of the opto go to 0V? If you put 0V on pin4 of the midi_in, does pin 6 of the opto go to 3.3V? If yes, then at least your opto does work.

The signal will be too fast. But if you put 5v DC at the opto coupler input, tell us what you see at the ouput. And if you gnd the input?

One more thing you could try, is connect the midi signals direct, no opto coupler.

Can you measure the DC voltages with the input low and also with input high?

What is the advantage of arm_rfft_fast_f32() over arm_cfft_f32()?

Yep, good catch Paul.

I just checked an old project of mine. My 6N138 opto worked fine with the default 220R as drive limiter and 470R as the receive side.

Thanks for sharing that. Will go through that code with great interest..

Lower that 220R a bit. And try various alternative to that 470R Or just use a faster optocoupler?

yes, if the noise is still present with the ADC grounded (meaning, the input of the ADC shorted to GND, so no signal can reach the ADC, no noise and no EMI), all the noise that you still get is inherent from your data aquisition system, and unrelated to your sensor of signal conditioning...

Incredible!!! A teensy controlling 4185 horsepower ��

Noise (hiss) or EMI (buzzes) ? Is it still there when you ground the input of the mixer?