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This article uses modulation tricks to try to get many inputs all on one audio channel. However, USB sound cards, available for around a dollar[1] have a nice
by londons_explore 3y ago
This article uses modulation tricks to try to get many inputs all on one audio channel.
However, USB sound cards, available for around a dollar[1] have a nice high input impedance and can directly be connected to EEG probes for direct sampling of microvolt level signals. No circuitry needed!
You can easily connect hundreds of them to the same system and get hundreds of input channels with great electrical isolation. The way USB works, they also have perfectly synchronised clocking too!
[1]: https://www.aliexpress.com/item/1005004134024654.html https://www.aliexpress.com/item/1005004134024654.html
- aidenn0 3y agoThey use modulation tricks to get multiple inputs on one audio channel. Sound-cards with more than 4 audio channels are not cheap, and if you gang multiple sound cards together you end up with clock drift. If you want more than 4 channels that don't drift from each other with consumer hardware, then you'll need to multiplex (And indeed, they offer non-multiplexing 4-channel options).
- 1MachineElf 3y agoYour link directed me to an AliExpress page with the words: Sorry, the page you requested can not be found:(
- appleflaxen 3y agoSame
- londons_explore 3y agoCurious. Link works for me even logged out. Anyways - search 'USB sound card' and sort by cheapest with free delivery and it is the one that costs $1.23. The comments show a teardown and it has an epoxy blob and a handful of passives on a small circuit board with two 3.5 mm jacks and a usb plug.