Muse S Athena Support

[VMinhoto]

I am trying to connect Muse Athena. When pressing start streaming a window opens for a fraction of a second and then crashes. Is this band compatible?

The log file is as follows:

2025-08-05 14:06:36.740 [Information] BlueMuse started.
2025-08-05 14:06:52.835 [Error] Cannot toggle characteristics (start=True) due to unexpected null GATT characteristic (UUID=273e0003-4c4d-454d-96be-f03bac821358).
2025-08-05 14:06:52.835 [Error] Cannot complete toggle stream (start=True) due to failure to toggle characteristics for EEG.

Any way I can make the band work?

Thank you

[kowalej]

@VMinhoto - I think what's happening is that BlueMuse is detecting the Athena as if it were one of the older devices (it either thinks it's a Muse / Muse 2, or Muse S), and is trying to use a corresponding Bluetooth profile that does not work for the Athena.

It seems like the Athena has both EEG and fNIRS, and should be most similar to the Muse S. However, I'm guessing that one of two things is going on (or a bit of both):

1. They changed the number of EEG channels or remapped the GATT characteristics (so the channels may now have different UUIDs).
2. The device is essentially the same as the Muse S, but with additional channel(s) for fNIRS, and perhaps less EEG channels?, but BlueMuse is not applying the Muse S profile. In other words, the device "model" detection is not backwards compatible.

If it's 1, I'd probably need an Athena device (which I don't have), and it may or may not be straight forward to engineer a profile to make it work.

If it's 2 - we can probably debug together at some point if you have time and determine what's going wrong.

Looking at the logs, I believe we are in scenario 2, since I don't see any error message regarding device detection.

You can see the code for device detection here, it could definitely lead to some undefined behaviour if some channels have changed:

BlueMuse/BlueMuse.App/MuseManagement/Muse.cs

Line 205 in edceed9

public async void DetermineMuseModel()

What would be useful is if you could install Bluetooth LE Explorer on your PC, discover your device, and go to the profile. Then provide me screenshots of the information. Here's an example of what you should see:

[VMinhoto]

Here you have the screenshot!

[kowalej]

The first 2 services are just some generic BLE and device info type stuff, so we can ignore them. The last service listed matches the expected data service used on the other Muse devices. My guess is the data service isn't showing all characteristics underneath though.

Service: 0000fe8d-0000-1000-8000-00805f9b34fb:

• 273e0001-4c4d-454d-96be-f03bac821358 - this is the GATT char to toggle the device modes and start / stop streams, so that's expected.
• 273e0014-4c4d-454d-96be-f03bac821358 - unknown, might have to do with new fNIRS?
  -273e0013-4c4d-454d-96be-f03bac821358 - unknown, might have to do with new fNIRS?

Here's what their specs say the device has:

• EEG Channels: 4 EEG channels + 4 amplified Aux channels
  -Accelerometer: Three-axis @ 52Hz, 16-bit resolution, range +/- 2G
  -Gyroscope: Three-axis @ 52Hz, 16-bit resolution, range +/- 250dps (New)
  -PPG Sensor: Triple wavelength: IR (850nm), Near-IR (730nm), Red (660nm), 64 Hz sample rate, 20-bit resolution (Upgraded)
  -fNIRS Sensor: 5-optode bilateral frontal cortex hemodynamics, 64 Hz sample rate, 20-bit resolution (New)
• Aux Channel Connection: Input range: 725uV AC signal (1.45mVp-p) with 1.45V DC offset; Aux channels are amplified like all other EEG channels

I would expect to see a lot more GATT characteristics.

@VMinhoto - it may be possible to use the Explorer app to look at the data while the device is being used with the official Muse app. It might show all it's channels while streaming.

[nictheboxer]

Hi Kowalej,

I wonder if you have made any more progress - I saw your recent message under muselsl also. I have the device since yesterday and can provide you with screenshot of data as you need. Also James creator of Mind Monitor has had his app working a few months back with some helpful notes in here: https://mind-monitor.com/FAQ.php#footnote-optics, not sure if this would be useful to yours.

[kowalej]

@nictheboxer - we're making progress. I've been chatting with some folks on the NeurotechX Slack and I've managed to get an HCI snoop log off of Android from an Athena user. The control protocol is mostly the same as the old devices, but the data encoding is different, and we're still trying to figure that out, as well as what one of the GATT characteristics is for.

Considering the change in how the data is streamed, it will probably take more work than I would have liked to add support in BlueMuse, but it should be doable.

I'm 90% sure MindMonitor uses official Muse SDK (requires licensing) which is why they were able to get it working. Their notes are helpful.

[VMinhoto]

Hey!

Sorry for my absence, I've been away from the lab the last couple weeks. I'll be back at the end of the month and will be able to try to debug it and provide all the necessary information. Will also be available to talk and debug it live and be involved in the process as this topic is in my interest.

Thank you very much for your support!