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I thought that freezing without a Ethernet cable connected is a known issue.

I bought a USB hub with power supply and now the teensy COM port is just there; problem solved. Prolly a USB power issue.

Thanks for the tip. Something like that might be the case, since the CS42448 CODEC draws some significant current and gets hot.

New info: with my CS42448 multi-channel audio CODEC sketch, and the CODEC IC breakout board attached, the COM port disappears. With the CODEC IC board disconnected, the COM port does appear.
...

I cann't open the Serial Monitor, as no COM port is available.

Upon an 15sec reset, and the 2sec Blinking programs is started, I can upload a sketch via Port : " hid#vid16x....... (strange...

OK, so I did reset the teensy 4.1 by pressing the button 15 sec. I could see a single red led flash, and upon release and 30sec waiting, a 2 sec Blink program runs. Upon compiling and uploading my...

OK, good to know and will try that.

Thanks for the fast replies gentlemen. Didn’t try the 15sec reset yet. Furthermore on my other computer, a laptop, a COM port 6 or 7 does appear....and I can use the serial monitor! Will report back...

Upon connecting my teensy 4.1 to the USB cable, it wont show up anymore as a COM7 port, not in the win10 Device manager, and not in the Arduino > Tools > Port. My teensy 3.6 and 4.0 show up...

Interesting remarks, thx

There is the Texas Instruments ADS1278, 8 ch , 144kHz, simultanious ADC and the Analog Devices AD7768, 8 ch, 256kHz, simultanious ADC both 24 bit, but not as fast as the ADS8885.

Following!

Looks like a nice DAC. How fast is it?

Maybe place the mutt on top of a mems microphone? as soon as the mutt is being moved this should cause a use contact sound. Trigger the camera from a sound level detector?


PDont think you even...

BTW. Using UDP or Serial is almost the same in MATLAB.

Real-time means time-deterministic. You should specify ur max allowed latenctly, which is not the same as saying real-time.

Matlab has UDP data transfer functions. I have gotten beyond 80mbit with matlab.

What bitrate do you need? You can try Ethernet which will give you up to 80..90 mbit per second.

Datasheet has no noise data (except for a 100Hz quote, which is useless because 1/f is a bit high on this part). The Spice model is pretty accurate too, and it has a low source-resistance. From...

1.5nV. Got one on my bench now. Read TAOE

You mean, creating a sparse sampled array? Sorry, dont know much about that.

Ad743, AD745 are fast enough for 1kHz sounds, LT1113, LT1792 and the newer ADA4817 are low noise candidates from Analog Devices. The sub 1nV preamp in TAOE is in figure 3.3.4 page 152.

OMG, did you see that price?

You can get those in SMD for 38cts/piece, or 10cts/piece per 1000. But try the opamp first, opa1642 or 1654, opa134 etc...

PS

I don’t understand the unit on that Y axis. Shouldn’t that be dB re 1uPa/sqHz. ?

Some comments:

For low noise you can try J309,LSK170,LSK489,INF3601. J309 is 35 cents and will be much lower capacitive load too. Look in The Art Of Electronics 3rd edition for a 1nV/sqHz preamp...

that is a nice website with examples... You could start with something simple as this: 23510

Well, I would keep the signal analog and design an analog switch bank. Or were you thinking ADC to teensy routed to serveral DACs?

You can use 12 switching JFETs like J175. Use 12 GPIO to turn on and off those JFETS.

Single GPIO and a resonator tank after it. Modulate the amplitude with a LDR? Or JFET?

https://sound-au.com/

Thanks Paul! :D

Best of wishes for 2021 to everybody.

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I thought there was another reply... but it seems to be gone :D

Is you hiss as loud as speech at 1 meter? That would equal about 60 to 70 dB. If so, then something is not right. The hiss should be atleast 20dB lower. Or 1/10th of a speech signal at 1 meter.

Next. See what the analog output is of the electret module at your intended SPL. See if you have high enough sensitivity.

IIRC that electret module has a sensitivity adjustment pot.

It might...

Find out if your ADC reads zero-ish with a low values potenter. And find out what the high values at 3.3v too. Might be better to use an lower ADC reference value to ensure that the electret...

The ADC has an effective dynamic range of 13 to 14 bits. That depends on how low you can get the source impedance driving the ADC. So expect at least 4 to 5 bits of random fluctuations rms That’s...

ADAfruit isn't selling garbage. The MAX4466 will get you to 30dBA if used correctly. Long wires dont cause hiss. An opamp with enourmoud bias current like the costly AD797 is a bad choise for a...

The MAX4466 should be able to getdown to 30dBA.. that pretty silent and very suitable to pickup voices from 1 mtr distance, prolly not good enough for distant bird sounds. If you cannt get descent...

These number really depend on you microphone. It normal for a electret mic element to have a building impedance converter that has around 50 to 100 nv/sqrtHz noise. BJT input opamps such as the AD797...

Maybe the microphone isn't able to drive to ADC to its full range?
Or maybe the ADC input isn't biased halfway its range (3.3V / 2 - 1.65 volt)?
Use the 16 bit ADC bit depth to ensure you dont...

Looks like a cool project, but with only 2 channels ADC, not interesting for me personally.

Then you shouldn’t call it noise.

It is important to keep the impedance to the ADC input as low as possible, so removing that 10k//1n might help. Does it happen when you short the input jack to...

A single coil has about 6nV/sqrtHz noise, a hum bucket about 10nV. That op amp has 18nV noise and that 10k resistor 13nV. And than the ADC... assuming about 10 LSB rms over 20kHz BW and 3.3volt...

For this I have been working on Ethernet. A UDP connection via the Ethernet breakout board.

THD of audio equipment is measured by rejecting the fundamental. That way a scope is fine too.

That would be great.

Somehow I missed this topic, but this looks great!

Are these PCBs for sale, or even the ready made populated PCB. I would like to buy a handful.

High quality audio codecs are benificial for non-music project too! Like ultrasoon, active noise cancelation and hydrophone projects.