Ganglion testing with a function generator

2

Comments

  • wjcroftwjcroft Mount Shasta, CA

    @fdarvas said:
    its an android phone - I tried both, drive & direct download - none of them work - I can see the file, but the nRF updater doesnt recognize it as a valid zip file. Ironically I have other, non-firmware related zip files there, that it will let me select. Originally I downloaded the file to my PC (windows) - so maybe windows is doing something with the zip ?

    Sorry you are having this issue. I hope Philip or Richard @retiutut or @Shirley comments. I'm wondering if the zip file name might contain some character(s) that nRF is not recognizing?

    The page listing the apps for Android:

    https://docs.openbci.com/Ganglion/GanglionProgram/#install-applications

    Shows two potential apps. Have you tried the other?

  • I rezipped the file with Linux and now it works - alas it then just fails, claiming that there is an invalid or too large file. Strange, since the zip is just 37 kB

  • ok - I finally succeeded - DFU for andriod is probably the worst app to do this - it simply refuses to open the firmware zip via the 'file -select' button - what worked in the end, was to select the zip file in the download folder and use the 'open with' option ,then select DFU to open it.

  • edited October 2023

    Can you check how large the zip file is in your Android downloads folder? It should be 51.3KB. If it's 37KB, then it's possible the download was corrupted. That's strange though since you mentioned that you downloaded it a few times, but worth checking. It's a normal zip file so you should also be able to extract it in an Android file viewer and see the included .bin and .dat files.


  • this is channel 4 (differential) with no signal and no filters.

    and this is with 200 mV Peak2peak 10 Hz sine wave, with a 100 mV DC offset over a 20/5717 Ohm divider - so the voltage where I used the differential inputs across the 20 Ohm resistor should be a 10 Hz sine wave with 200 mV *20/5717 = 699 uV amplitude.

  • wjcroftwjcroft Mount Shasta, CA
    edited October 2023

    Is it possible that your previous upload attempt failed and you are still running the old firmware ?

  • Can you also update to GUI version 5.2.2? Support for the new Ganglion firmware was added in this release.


  • same input signal

  • I would say it looks somewhat better with the right GUI, but still....How do I know I have the right firmware on the device?
    According to DFU, it did successfully update and I powercycled the device after the update.

  • wjcroftwjcroft Mount Shasta, CA
    edited October 2023

    @philip_pitts said:
    Can you check how large the zip file is in your Android downloads folder? It should be 51.3KB. If it's 37KB, then it's possible the download was corrupted. That's strange though since you mentioned that you downloaded it a few times, but worth checking. It's a normal zip file so you should also be able to extract it in an Android file viewer and see the included .bin and .dat files.

    Felix, hi. Can you confirm that your zip file was 51.3KB on the phone? As Philip suggested previously?

  • There's a couple ways you can check if the firmware has been updated:

    1. If the firmware has not been updated and you are running GUI v5.2.2, you should see a popup prompting you to upgrade your firmware after starting a Ganglion session.
    2. If you are running Ganglion v3.x.x your device should show up as "Ganglion 1.3 (xxxx)" when searching for the device in the GUI.
    3. You should see a line in the GUI console log that says "[DEFAULT]: Detected Ganglion firmware version 3".



  • It seems I have the correct firmware? It shows version 3. My Ganglion shows up as 1.3(8490).
    But the signal still looks bad.
    I will try to hook it up to a known good other EEG and see, if I am feeding it a bad signal, but from previous experiements, even though the resistor is noisy, it should not look like this.

  • wjcroftwjcroft Mount Shasta, CA

    Was your zip size 51.3K, as Philip asked? If NOT, is it possible that the V3 that you uploaded was partially corrupted? And 'identifies' itself as V3, but in fact does not have the complete correct binary contents.

  • edited October 2023

    yes, the original zip file was 51.2k (52514 bytes , 53248 bytes on disk) - however, after unpacking and re-zipping (to get it to work for the android app), the actual size was just 37k. However, the DFU app reported a sucessful update of the firmware.


    Same 200 mV pp , 100 mV DC offset 10 Hz signal for the 20 /5717 voltage divider.

  • wjcroftwjcroft Mount Shasta, CA
    edited October 2023

    Philip has mentioned that he was able to upload the original 51.2K file with your workaround:

    Philip Pitts: I also just double checked and I can load it directly via DFU (without the open with workaround)

    and you remarked previously: "what worked in the end, was to select the zip file in the download folder and use the 'open with' option ,then select DFU to open it."

  • edited October 2023

    yes - So I went ahead and tried that with the original file, and the "open with DFU" did succeed (see above posted screenshot).

  • wjcroftwjcroft Mount Shasta, CA

    @fdarvas said:
    yes - So I went ahead and tried that with the original file, and the "open with DFU" did succeed (see above posted screenshot).

    So... The new upload of size 51.2K installed? But your test results look just the same as before?

    Can you use an oscilloscope to check your test signal?

  • wjcroftwjcroft Mount Shasta, CA

    A 100 millivolt (.1 V) DC offset is pretty severe. No biological system will exhibit this.

  • The offset is just to bring the signal into a range of 0 - 200 mV total - keep in mind , that the voltage divider brings that down to 3/1000.

  • Or maybe it did throw it off - this is 100 mV pp without offset - so -50 mv to 50 mv , same voltage divider. I think this looks actually quite reasonable, given the noise on the resistor.

  • There is a cross over point where it fails:


    This is 150 mV pp

    this is 140 mV pp

    So it seems, that there is a sweet spot, where the compression just doesnt spoil the signal yet.

  • wjcroftwjcroft Mount Shasta, CA

    Have you confirmed that your 10 Hz sine wave signal, 200mv peak to peak (input to the Ganglion) -- looks as expected on an oscilloscope? So your offset is to just produce a sine wave, centered at 0mv, swinging between plus and minus 100mv ?


  • Or not - this still happens at 100 mV pp - as can be seen on the scale, the signal is actually quite small (it should be 349 uV, so that question is still out there, why its just showing as 10 uV or so??)

  • This really looks like the old firmware, but I agree from your screenshots that version 3 is being detected. A couple more questions:

    1. Are you periodically losing packets as reported by the Packet Loss widget?
    2. Can you use the nRF Connect app to check the Software Revision String of the device? Instructions below.

    Checking the Software Revision String:

    1. Install nRF Connect
    2. Find and connect to the Ganglion device.
    3. Click on Device Information
    4. Click the download icon next to the Software Revision String

    You should see "3.0.1" as the value. If you see something else (e.g. 3.0.0) you may not have the latest v3 firmware and should download and flash it from the GitHub release page.

    Note that nRF Connect is an Android app so if someone from the future is looking at this post, they may need to use a different Bluetooth scanner depending on their OS.


  • This is the HackEEG output for the same 100 mv PP 10 Hz signal.

    So, yes, it is a lot of noise from the resistor, but otherwise as expected.


  • For 500 mV PP on the voltage divider - so the resistor noise is smaller relative to the amplitude.

  • So, my input signal from the function generator looks good I think.


  • I think it is the 3.0.1 firmware

  • I was able to reproduce the problem and we will push out a fix for this soon. The issue only occurs for me on Channel 4. Would you mind trying the other three channels to confirm?

    https://github.com/OpenBCI/OpenBCI_Ganglion_Library/issues/24

  • Strange enough, I only get any kind of signal on channel 4. All the other channels just dont seem produce any meaningful signal.

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