I reduced the pics and the post works… so here is a quick outline: not to clean but wanted to get it out there.
With an xacto knife or small scissors cut around the pad on 3 sides. (leave the side closest to the snap that is on the back alone)
to be honest, I am not sure if this is needed, You may able to simply add a snap to teh existing sensor, but I did not have a second sensor and I as pretty sure that it would work if I mounted the snap on he back of the cloth, where there is still good silver… If someone has some work out pads and can send them to me I will test putting the snap on over the foam. I will ten measure the resistence, and test it with my bed side unit. If it does not work, will pull the foam and add snaps and send it back to you. (LIMITED TO THE 1st one to PM me ans say that they want to do it… ) Do it quickly, because I head out on a trip early December for 9 weeks.
Red circles are the studs out the back. Red lines are roughly where you cut on 3 sides.
Pull back the cloth and pull out the foam pad.
Twist over the sensor so that the back of the cloth is now facing up. I did this becasue the back should still have silver on it…
Center a no 16 snap and press the prongs through from the back
Place the “socket” over the prongs and press in place.
The snaps I bought from hobby lobby will hold the eeg electrodes. They are not to tight, but they do hold. I am looking for a better snap and have some samples coming.
I also had problems with the snap setter from hobby lobby. I tried making some replacement electrodes, but I smashed the stud flat when trying to set it. I have a lathe so I made a punch by drilling a 1/4 hole in a small rod. This allows the punch to press the outer edge where the prongs are set and not mess up either the plug or the socket. It also let me collapse the section that the prongs get into making tghe snap more secure…
There are also some other snap setters out there that may work for less. (have not tried this one, but it looks like it might work… not sure how long it would hold up, but the price is right…
http://www.joann.com/dritz-snap-fastener-ineasy-attachmentin-kit/2614915.html
I think that you get 4 snap sets, so you should be able to put the 3 sockets you need. BUT I THINK THAT THERE ARE BETTER SNAPS OUT THERE… still looking.
The electrodes I bought were expired and offset. I trim them down to just outside of the sensor pad.
I tested the resistence between a section of protected cloth and my snap, it was 5 ohms… it was abpout 35 ohms to the plastic snap on teh back… I am pretty sure that it is hi because it is a conductive plastic.
I am testing making new cloth pads.
NOTE: If you make a test pad and use the no 16 snaps from the set, it is a very thgit fit the first time… It actually expands the socket and the eeg pads no longer stay in place…. Do not ask me how I know……:@:@ … That is why I am looking for a better snap socket. I think I found one that will hold up better, but need to call them on monday and get a sample sent. My goal is to have a headband that will work with disposable eeg (because I have them now) or will work with a replaceemnt cloth one that I am going to test.
I am working with the R&D department at MEDTEX to see if they have a way to make a replacement sensor, that does NOT require making a whole new headband. I am thinking that the snaps may work, or they make a conductive velcro… If it works I will update this thread or start a new one.
By the way, for people looking to use the indestructable thread out there. I am 99% sure that it will work better using MEDTEX 130 cloth instead of the 180 mentioned. The 180 only streatches in 1 direction. The 130 streatches in 2 directions and will probably streatch over the foam a little easier. It costs a little more, but it will probably be easier to work…
I also measured the thickness of the foam in the existing headband. It is about 1/4 inch think open cell foam…
and just to keep it fun, I have some samples of 3M double stick tape coming. One of them is 1/4 inch thick open cell foam… You can probably see where I am headed with that thought…
If this works I have 2 thoughts about supplying them, both are just ideas:
- I have a son who may be interested in making them and offering a replacement backing pad and sensors.
- When I was in St. Louis there was a “Sheltered Workshop” that allowed (not sure how to say it now, it use to be “handicapped” people) to do some of the easy and repetative task for the local industry… If this works, and I can find a similar workshop down here in Dallas, I would work with them and set up the tooling to make the parts. I am pretty sure I could break down the process to simple steps, and with some tooling ensure that the snaps are always in the same place… BUT THIS IS A LONG WAY OFF.
I have ideas for a replacement sensor:
- super simple - cloth wrapped around the double stick tape and a snap on the back it would not be as pretty but would work… and be cheaper
to the super nice.
- think oif making a small pocket 1/2 inch square, fold it inside out, put in the foam and get a snap on the back and tuck a flap in, so it is a nice clean tiddy pad.
Personally I am planning on making teh super simple ones for my own use and see how they go…
If it were only for me, I would go with the super simple. Ther may be some fraying of the cloth over time… but I would put up with that. I am hoping that the double stick tape will stop the fraying… will have to test it… If not there are some other options, but all add time and cost.
SO…
( maybe ai should seperate this out and make it a poll ??? )
If I can get a replacement pad to work would you rather pay for:
-
a super simple one for roughly $8 -$10 per set of 3 (If I can work it out I may be able to drop even lower)
-
or a fancy one but the cost would double… (maybe more)
BUT FIRST I NEED TO BUGS OUT.
- a reliable snap (or switch to velcro)
- a padding material to provide the right give
- a design that is acceptable but does not drive up the cost
- some one to make them (I am willing to make them for a while, but have some limitations that prevent me from doing it long term)
Thanks for any feedback.
If you convert yours to snaps, let me know how it goes.
again. sorry about typos, and the rambeling… this post already took 2 hours… I have some challanges 
I will have to get my wife to edit a cleaner version with just the conversion, if there is enough interest in getting that as a cleaner post.
