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Yes that would be expected from the sims and from actual performance, particularly if you're (not at all unreasonably) modelling the electrodes as being of unequal impedance, and the higher the impedance the worse it'll be. Since there are a lot of…
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Hmm, my pointer to the schematic on github doesn't seem to work for me. Just goes to show how little I know about that sort of thing. Maybe you know how to find it if I say that it's on github, OpenBCI / Ganglion_Hardware_Design_Files / Ganglion_S…
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Hi Mark. First, about differential and common mode, they're not the kinds of mode where you would put the device into a certain mode. Instead, it's a matter of which pins of the device are being driven; and often they're being driven partially in …
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This is regarding the above-mentioned possibility of reducing V_REF to +0.50V, by dividing the REFOUT pin of the MCP3912.What's a pain is that the resistors would need to be large enough in value so as not to unacceptably alter the voltage at REFOUT…
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Yes based on its spec I'd say that although the MCP3912 doesn't have a negative supply delivered to it, it's designed to perform within specs with incoming signal voltages in the range from -1V to +1V relative to its ground which is our board's AGND…
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The terse "yes" seems like a sufficient answer to ccake's specific question.Plus, I think/hope there's an implication that all shipments purchased on or after Dec 1 2017 do/will have the fix. (By saying that, I don't mean to imply that no shipment…
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Hi hamza, I can't speak for openbci designers & others knowledgeable about all the choices, but here's one pointer .... The Ganglion ADC-etc-chip MCP3912, desirable for Ganglion partly because of lower-cost than Cyton's, has fairly low input …
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Hi GregoryC, I think the mentions for @biomurph or @openbci or @somebody are good. ........ Regarding the 10-second dataset at https://github.com/OpenBCI/Ganglion-Prototype-Data, I'm thinking that without more contextual info, those data ar…
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biomurph: The AFE chip's AGND is Ganglion's GNDA which is Ganglion's ground. Maybe you were referring to D_G which a person could think of as analog ground for the patient. Xp0: Yes, need to divide that signal down ... certainly to be able to see…
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Hi, I'm wondering what came of this, seems some stuff didn't get answered. 1. What was the date when production units began to be built with the revision. If there's no clear date, datecode, etc., then the best you have. 2. What was the chang…
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yumin -- If you stay with 200 samples/second sample-rate, you won't need any of the following. But if you are able to change to a higher sample rate and you want to go for higher frequencies of some sort, notice this. Ganglion has a resistor-…
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Yes, on Ganglion there's a hard-set mid-band gain of 51, in the instrumentation amplifier stage.Then the signal goes into the AFE, the first stage of which is a PGA for each channel, SPI-command controllable for gains of 1, 2, 4, 8, 16, or 32.
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Hi Xp0, Here's what seems right to me ...I'll pretend you're only going to use channel 1 ... and you have its input switch position so that 1_IN- is used, not REF, if you know what I mean. For just "voltage noise", connect 1_IN+, 1_IN-, and D_G…
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Hi Sam, I'm pretty much hardware-only, but I'll add some. William's comments make all the sense in the world to me, with short wires, minimal wire-movement, minimal variation of forces on electrodes, etc, plus wires should be snug to the cap, a…
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Thanks William, it seems you were right, that dongle seems defective, intermittent, only rarely works. Upon trying the one I then got on amazon, it immediately worked and hasn't quit since, after many usages for a few weeks. I'm so relieved. It h…