Snapped electrode wire on Ultracortex IV electrode holders (sell replacement crimp nuts?)

sarah_mclsarah_mcl Halifax
edited August 2018 in Headware
A few of the electrode wires on our Mark IV headset have snapped off where the wire meets the crimp (see photo below).  We think this was caused from twisting in the electrode while the wire was connected, and will avoid doing this in the future.  My question is, has anyone had this happen before, and how did you fix it? I could solder the wire to the crimp but I'm not sure how durable that would be.  Any suggestions?

Thanks!

image

Comments

  • wjcroftwjcroft Mount Shasta, CA
    Mentioning @openbci, @Conor, @biomurph.

    Sarah, hi. You are correct, trying to solder the broken wire back onto the exposed wire at the end of the crimp / nut is unlikely to be as solid of connection as it was originally. If the lab can supply a link where more crimp connectors can be ordered, that would allow you to strip a bit off the existing wire, then crimp onto a new connector.

    Is this crimp / nut combination a single piece? It might be made up of a male / female threaded hex cylinder, and then the crimp cylinder bridging between the male thread and stripped wire. If that is the case, then you may be able to remove the old crimp cylinder (with some pliers and inverting the crimp at 90 degrees, twisting pulling). I don't have one of these right in front of me, but here is a closeup.


    image

    Regards,

    William

  • sarah_mclsarah_mcl Halifax
    Hi William,

    Yes, the crimp and hex appear to be a solid piece like the one shown in your photo. I couldn't see any way to take it apart, but if it's possible to order new crimp connectors that would be great.  As an interim solution we will likely combine some parts from an older generation headset, and use the longer screws and nuts to hold the electrode wires in place.

    Thanks for the help!

    Sarah
  • wjcroftwjcroft Mount Shasta, CA
    Andrea @openbci, can OpenBCI provide a way to order additional hex crimp nuts for repair of the Ultracortex electrode assemblies? This could either be a manufacturer / part number, or a small kit of say 5 to 10 crimp nuts listed on the store? (And orderable from contact at openbci.com in the interim.)

    William

  • shanksshanks Vienna
    edited May 2018
    [new thread titled: hex crimp nuts and the ear clips]

    Hi, 

    has anybody found a store (or multiple stores) in Europe where all the parts for the electrodes can be bought? 
    I am particularly looking for the hex crimp nuts and the ear clips. I can't find those two things anywhere.


    Thank you for your help!

    Best
    David

  • wjcroftwjcroft Mount Shasta, CA
    @shanks, hi.

    I merged your post into this existing thread. I believe there will be someway to get replacement crimp nuts.

    Can the the OpenBCI lab please respond? Mentioning @Conor, @openbci, @biomurph, @Shirley.

    William

  • jessicalokejessicaloke
    edited June 2018
    After multiple usage, many of the dry electrodes provided with the Mark Cortex headset has its wires snapped off (see photo). I do not see an option to only buy the electrodes in the OpenBCI shop. Where can I purchase the exact same electrodes to continue with the rest of the experiment? Thank you.
  • wjcroftwjcroft Mount Shasta, CA
    Jessica, hi.

    I've merged your post from today into this existing thread. This question has come up before as you can see from the previous posts. Rather than needing to replace the entire electrode holder assembly, it should be possible to just unscrew the crimp nut, strip a bit of insulation off the wire end, and crimp the wire onto a new crimp nut. (Then thread the new crimp nut onto the bolt.)

    It might also prolong the life of this joint between wire and crimp nut, if a piece of shrink wrap tubing was placed over the end of the wire before crimping. Then sliding that down onto the joint and using a hot air gun to shrink the tubing over the joint. This could provide strain relief to the wire/nut joint and avoid repeated breakage.

    Can the the OpenBCI lab please respond? Mentioning @Conor, @openbci, @biomurph, @Shirley.

    William

  • jessicalokejessicaloke
    Hello, William. Thank you for your response. I guess now I have the same question as shanks/David on the possibility of purchasing these additional hex crimp nuts online in Europe? 
  • JoRip1JoRip1
    edited August 2018
    [new thread: Wires "snapped" from the electrode]

    Hello,

    If the wires have been "snapped" off the electrode, is there a way, such as soldering, that I can fix these electrodes?

    Thanks
  • wjcroftwjcroft Mount Shasta, CA
    @JoRip1, hi.

    I merged your new thread question on the snapped off wire into this existing thread on the same subject.

    My understanding from an email I exchanged with the lab in June, was that they were planning on listing replacement electrode assemblies (the entire electrode holder plus wire), in the OpenBCI shop store. However I just checked the shop and do not see that item listed yet.

    Another way to go that I suggested previously in this thread would be to sell a small package of say 5 crimp nuts, so that users could do their own repair. One other enhancement that could be done to make this more robust, would be to slide a heat shrink tubing onto the wire/nut junction after crimping. (Then heat gun to shrink down onto the wire/nut junction.) This would act as a wire "strain relief" to take the strain off of the junction point. That suggestion was well received but I'm not sure if/when it will be implemented. You can always do a kind of makeshift on your own using your own tubing or decent electrical tape.


    I suggest you email contact at openbci.com and ask how you should proceed to get replacement holders or nuts.

    Regards,

    William

  • QozQoz UCSD
    Since this 'crimp nut' is still not offered on this website and I can't seem to find anything remotely similar anywhere online, has anybody successfully tested an alternative? I was considering buying some brass/aluminum spacers and soldering them to a jumper cable, but I'm not sure what the result would be in terms of signal quality/impedance.
  • wjcroftwjcroft Mount Shasta, CA
    @Qoz, hi. It could be that the individual replacement UC IV electrode assemblies may only be sold to existing customers, and thus are not listed on the shop page. Have you tried emailing to contact at openbci.com and asking how to place your order? When you get a reply, post the answer here.

    My understanding was that the crimp nuts were not going to be offered, partly because if not crimped right or with the right tool, the newly installed crimp nut may fail early because the wire joint is stressed.

    Of course the answer to these breakages is to unplug your electrodes before doing large numbers of positioning rotations. This is mentioned in the tutorials.


    Regards,

    William

  • QozQoz UCSD
    @wjcroft, I'll check the shop on an account which has made purchases, and I'm currently in an email chain with @Conor, so I'll update this thread when I get more information.

    That rationale makes sense, although it would be nice for us to have a DIY solution .

    I do unplug the electrodes nowadays, but I only figured out this was the best strategy after snapping an electrode!
  • wjcroftwjcroft Mount Shasta, CA
    @Qoz, hi. Were you able to order your replacements?
  • QozQoz UCSD
    edited January 2019
    @wjcroft I haven't had a chance to investigate this further yet; the account which purchases equipment belongs to my director, and we've been very busy lately! I'll update this thread as soon as I find out more information.
  • dbisigdbisig Switzerland
    Hi all, 

    I'm also very interested in obtaining replacement crimp nuts, ideally already with the cables attached. Is there any update on where these things can be bought in Europe?

    Thanks a lot and best regards

        Daniel
  • wjcroftwjcroft Mount Shasta, CA
    edited February 2019
    Daniel, send an email to contact at openbci.com .

    It would be helpful to all those posting in this thread, if @openbci, @techsupport, or @Shirley or @Conor, posted the recommended steps for ordering replacement parts. It might be that emailing contact at openbci.com is the action required, but posting pricing information, Europe availability, etc. would help those customers encountering the broken wires.

    Regards,

    William

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