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Audio-Injector / Ultra

Ultra sound card - 192khz, 24 bit, microphones and balanced line addon.
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Low frequency vibrations - bandwidth from 1-50Hz #2

Open ghost opened 6 years ago

ghost commented 6 years ago

Will the Ultra be capable of recording vibrations from local traffic via a seismometer

I would be looking to record the voltage changes from the seismometer in the range of 1Hz - 50Hz. I understand the Ultra is capable of ultrasonic recording, but is it capable of "subsonic"?

flatmax commented 6 years ago

Hi there,

Yes, the base audio card is capable of DC input/output. They are differential pairs.

If you look here :

https://github.com/flatmax/AudioInjector.Octo.RCA

You will see schematics and gerbers for the layout of a passive interface. If you bypass the AC coupling caps, you can go down to DC. If you change the default 10uF AC coupling caps to something much bigger, then you can lower the cutoff frequency.

Alternatively you can design your own board !

Matt

On 04/07/18 02:19, tringwebdesign wrote:

Will the Ultra be capable of recording vibrations from local traffic via a seismometer https://mindsetsonline.co.uk/shop/lego-seismometer-kit/

I would be looking to record the voltage changes from the seismometer in the range of 1Hz - 50Hz. I understand the Ultra is capable of ultrasonic recording, but is it capable of "subsonic"?

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ghost commented 6 years ago

Interesting, but way beyond my skills set and knowledge, I was more after something off-the-shelf

flatmax commented 6 years ago

Can you solder capacitors onto an existing board ?

On 04/07/18 15:53, tringwebdesign wrote:

Interesting, but way beyond my skills set and knowledge, I was more after something off-the-shelf

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ghost commented 6 years ago

I have recapped an old Atari 2600 VCS from 1984 and soldered Geteron switches to a 96% mech keyboard PCB, so am comfortable with a soldering iron. I've currently been using the Cirrus Logic Audio Card for this experiment but again can't find out it if the hardware does filtering. Here's the thread

flatmax commented 6 years ago

Well my recommendation would be to attach bigger caps in parallel with the caps currently on the RCA board - this will lower the AC coupling cutoff frequencies.

On 05/07/18 13:17, tringwebdesign wrote:

I have recapped an old Atari 2600 VCS from 1984 and soldered Geteron switches to a 96% mech keyboard PCB, so am comfortable with a soldering iron. I've currently been using the Cirrus Logic Audio Card for this experiment but again can't find out it if the hardware does filtering. Here's the thread https://www.element14.com/community/thread/64399/l/is-there-a-low-frequency-cut-off-value

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chobbs22079 commented 5 years ago

I would like to work out how to do this. So, you are indicating that only the base board is used for the acquisition of the signal? Of so, the link you pointed to for the octo schematics: if it is the same for the ultra2's baseboard, can you specify which caps in the pdf need to be replaced and how the RCA connectors are mounted on the baseboard? I could not tell from the pdfs. Please let me know. Thank you.

flatmax commented 5 years ago

The ultra 2 is totally different to the Octo. However the Octo's base board is DC coupled. Basically with the Octo, if you interface its pins directly, you are going straight into the ADC and out from the DAC ! For that reason you may want to use your own preamp board.

You will have to experiment with it to find the right setup which works. The input lines you can bypass the caps on are the ADC_fb*+ lines