Auxilliary Electrodes


I’d like to purchase a set of auxiliary electrodes that are advertised to be able to be plugged into the micro-USB connector. However my local distributor states these cannot be purchased on there own, which is confusing because to purchase the headband from the ‘choosemuse’ website you’re directed to Amazon with no option to purchase the headband with aux electrodes.

Please advise as to where I’ll be able to purchase a set.


I don’t know where you can buy them, but it’s super simple to make your own.
For the MU-02 (BlueTooth LE) model muse, you just need to connect a wire to USB pin 4. There are no other electronics required. Just a micro USB male connector, some wire and solder.

What you put on the other end of that wire for connecting to the body is totally up to you. The ones I’ve seen used by Interaxon staff have snap fasteners on, so they can connect to commercially available skin electrodes.


Thanks for the reply - so just to confirm the the wiring would be:

MicroUSB pin 4 --> signal
MicroUSB pin 5 --> ground

Out of interest - do you know what the maximum input voltage is for the AUX input??

Muse-io time issue

The aux port is for bio-potential measurements, and is referenced to the same reference as the Muse (which is 1.65V above ground). The signal voltage range 2mV p-p. The aux channel is identical to the 4 standard channels.
The max voltage range (to prevent damage) = 0-3.3V referenced to ground. The signal is AC coupled, but it’s buffered before this so signals below GND or above 3.3v (when referenced to ground) you won’t get any signal.

Measuring the latency of sending data from muse / muse monitor

Psi_researcher (Chris),

Were you able to make/purchase an auxiliary sensor? Not being an electrical engineer, I’d be happy to purchase a sensor if someone has one to spare (or could make one).

James Weaver


I too need to add to the standard Muse electrodes a couple of additional electrodes.

Would someone be interested in doing this and selling me a pair? The technical documentation of the muse states:
"Auxiliary electrodes (enabled via [Settings] > [Show Aux Input]) can be connected on the Muse micro USB connector, by pin 4 on the MU-02 (BlueTooth LE) model."


can this electrode be useful?


No I don’t think so, it must be a single electrode only in my understanding, such that it is at this time, and you want an active not passive electrode for this connection.


@DSaund you just need a single wire skin conductor. No active electronics required. I would recommend using shielded wire and connecting the shield to the USB ground to prevent interference though.


Ooh, very nice. thanks for the correction. Would this be the case for a 2014 headset, or purely for the 2016? there seems to be a difference between them from what ive read on here.


Same, but the electrode wire connects to a different pin. On the 2014 it’s pin 2(D-) on the 2016 it’s pin 4(ID).


Hi Enigma,

Can you attach your homemade cable let we see :slight_smile: I was tried to make one , but when I connecting to the usb port somehow all incoming data disappear and the horseshoe losing it’s colours. (like a short circuit)


Make sure you have the correct pin for your headband version. My cables are fully potted, so a picture wouldn’t help you. It sounds like you’ve got the wrong pin if it’s killing all the other signals.


Yes, I definitely something wrong. I just ordered 10 pieces of micro usb from china so I can play with it. :slight_smile: