Sewing the Stretch Sensor

I have been trying to figure out how to best connect the stretch sensors to fabric. What I did before was simply using relatively thick multi-strand cables and attaching the stretch sensor using pressure fitting. I would then just sew the multi-strand cable to the fabric.


However, the rigid plastic parts required for the pressure fitting do not especially appeal to me, they are clumsy and don’t work as well as I was hoping they would.
I was hoping to find a method of making the actual sensor more stable and making it easier to attach the sensor to clothing. I ended up sewing the sensor and cable directly to elastic bands. This works fairly well, especially as the maximum stretch of the elastic is less than that of the sensor, protecting the sensor from being overstretched. Well … enough talk, take a look at the pictures to see how this looks in practice

Ahh… and ignore all the extra threads and sloppy craftmanship. Next-time round this will look a lot prettyer. My sewing machine and me *are* (slowly) becoming friends…

ShadowCoat Mouse

I procrastinate productivly: I should have been doing other university stuff, instead I thought... "can I use my set-up as a mouse?"

Well, I gave it a shot. I'll coment more on it later.

Introducing: The ShadowCoat (Part 2)

As mentioned before,  I have changed my approach a bit, dropping the thermoplastics and going more towards smart clothing direction. I suggest you just take a look at the video. I'll post some pictures and explanations below.

What is most noteworthy in the video is that the rotation of the arm does the two sensor thing I've been talking about (cant wait to see that work on the elbow and shoulder as well). This greatly increased the accuracy of the reading. Also, the software now out-calibrates. This makes the suit ultra-usable. A friend just tried it on and it worked as effortlessly with her as it did with me.





I am still using the stretch sensor by Images. As you can't soldier plastic, I had to find other means of connecting them to cables:

  

I use multi-core cables (ahh, I know thats not the correct term, but its late...), so sewing over/through/on them is no problem

I am sewing them to the construction I prepared yesterday, you can see them in this post.

I was fooling around with the readings from the stretch sensors earlier and realized, that using two sensors which counteract each other would greatly benefit accuracy and amplitude of the signal. I tried it, and yep, it works :-)

From my ShadowCoat :-) the sensors connect to voltage dividers which in turn connect to the Arduino Mega...

Here is what the whole thing (and me) look  like at the moment. I'm quite happy, cause this worked better than expected :-)

Ad Thermoplast

A guy who goes by the name of cr0sh on the Arduino Forums, who has been giving me all kinds of interesting suggestions, wrote a comment on thermoplastics. I will just copy paste it over here, in case anyone who has been following what I am doing is interested.

Personally, while the stuff *is* amazing, I am quite happy to announce, that it no longer is the main structural component of my set up.

Anyway, here goes chr0sh's post:

I noticed you are moving to customized forms using thermoplastic (Turbocast from Streifeneder, Apolit from Minke Props).

Whether or not it will help you (though it might help others, so you might want to reference it on your blog?), such plastic is known by a couple of different names in English:

"PolyMorph"
"Friendly Plastic"
http://www.instamorph.com/
http://shapelock.com/
...among others - its chemical name is:

Polycaprolactone (PCL) - http://en.wikipedia.org/wiki/Polycaprolactone

One place I found that sells "bulk" (not sure if "to the public", though) is:

http://www.absorbables.com/standard.htm

They also have "sample kits". You can also find this plastic on Ebay quite often, typically sold as plastic for jewelry making; it comes in a wide variety of colors (including metallics). Standard forms I have seen (before seeing your samples), have been a flat "stick" form, and pellets.

In the US, I have seen it sold in craft stores, and the friendly plastic is available from Target stores.

By the way, cr0sh has a website: phoenixgarage.org check it out :-)

Introducing: The ShadowCoat

I havent updated here in a while. I have sort of important news though (well, in a way)

I have decided to call my input device ShadowCoat because well, it copies your moves, like a shadow... and your can wear it, like a coat :-)

Oh, and for those of you who are thinking... "this thing is wearable, but no where near as comfortable as a coat..." ... well, I got out my sewing machine... I am not really ready to present what I am sewing, but I thought I might as well upload some pictures in the meantime :-)

 

I also built myself a new ArmBot: ArmBot II :-D

... this one is not as pretty (and thats a euphemism), *but* it actually has all the degrees of freedom I am measuring. This is a huge help - having something physical in front of me to controll makes things much clearer to me.