Time Sensing Bracelet




Introduction: Time Sensing Bracelet

About: My work combines conductive materials and craft techniques to develop new styles of building electronics that emphasize materiality and process. I create working prototypes to demonstrate the kinds of electr...
The Time Sensing Bracelet is a fabric potentiometer. You select your desired time of day by making contact in the corresponding position on your wrist - where your watch would normally be.
There is no point to it but fun.

Update: Using some wire wrapped around the central popper to make contact with the resistive ring (circular potentiometer). Unfortunately (though cool too) the Eexonyx fabric is pressure sensitive, thus its resistance varies also on the pressure applied, not only on the position of contact.
Plus, the contact between the wire and Eeonyx is not stable enough. But this is a design issue that can be solved:-)

Video of update that eliminates the conductive finger-cap

Video of Time Sensing Bracelet in action

Video of first prototype

Step 1: Materials and Tools

also see http://cnmat.berkeley.edu/resource/eontex_conductive_fabric
also see http://cnmat.berkeley.edu/resource/conductive_thread
also see http://cnmat.berkeley.edu/resource/stretch_conductive_fabric
  • Fusible interfacing from local fabric store or
also see http://www.shoppellon.com
  • Fabric scissors
  • Sewing needle
  • Iron
  • Soldering station (iron, helping hands, solder)
  • Knife for cutting perfboard
  • File for filing edges of perfboard
  • Wire cutters and strippers
  • Pliers


Step 2: Trace and Cut Stencils

Print out the stencil (see illustration) and trace it to a piece of neoprene. Trace the circle onto a piece of stretch conductive fabric that has fusible interfacing adhered to one side. Trace the disconnected ring and the small rectangle to a piece of Eeonyx fabric that has fusible interfacing adhered to one side.
Cut out all the pieces.

Step 3: Fusing

Lay the circle, ring and rectangle into place and fuse with an iron.
!Careful: the Eeonyx fabric will stick to your iron, be sure to put a piece of wax paper in between.

Step 4: Soldering

Cut a piece of perfboard 18 x 5 holes big. With the conductive strips running the shorter length. File the edges, but you do not have to round the corners, it is only for decoration.
Bend the legs of three male headers if you don't have any ready bent ones. Solder them to one of the corners of the perfboard.

Cut a piece of ribbon cable with five wires. About 1m long. Strip the ends of the 1, 3, 5th wire and solder to a row of three female headers. These will plug in to the three male headers on the bracelet.
Solder the other ends to the 1, 2 and 6th headers in a strip of six male headers, this will plug in to the 5V, GND and first analog input of your Arduino board.

Step 5: Sewing

Before sewing the conductive connections we need to sew the perfboard into place with some non-conductive stitches. We may as well sew the strip of Velcro to the other side of the neoprene while doing this. If you dont have sticky Velcro for the other side you will have to sew this too. Otherwise just peel and adhere.

  • The circle will be your +5V
  • The Ring will be your variable resistance
  • The rectangle will be your pull-up resistor

To understand the reason for having pull-up resistors, follow this link >>

The three conductive stitches come very close together and we want to make sure that they do not touch each other inside the neoprene, where we cannot see them. So you have to remember where you have stitched.

Sew from the circle of conductive fabric to the furthest left perfboard hole connected to a male header, bypassing the pull-up resistor.

Sew from the end of the pull-up resistor closest to the perfboard to the middle hole connected to one of the three male headers.

Sew from one of the ends of the ring to the other end of the pull-up resistor to the last hole of the three on the perfboard.

I attached a metal popper to the center of my conductive circle, because I wanted to be able to connected a piece of rotate-able metal to it, that I can turn and it will stay in one place making a constant connection there between the conductive circle and resistive ring.

One last thing we have to cut and sew is a little conductive finger-cap from stretch conductive fabric (no fusible interfacing). Trace your fingertip and cut it out twice, then sew together with conductive or non-conductive thread. Turn inside-out. Finished.

Step 6: Plug and Play

For Arduino microcontroller code and Processing visualization code please look here >> http://www.kobakant.at/DIY/?cat=347

Plug the headers into the right places and wear the bracelet. If all goes well you should be reading the inputs from the bracelet.

Now it is up to you to decide what time it is by placing your conductive fingertip wherever you want what time it to be.

Press the space bar to enter the visualization mode and press g to return to the graph mode. You can set the thresholds in the processing code.

Let me know if there are any complications. And enjoy!



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    28 Discussions


    I was wondering where the code has gone?? the link is broken


    Maybe, but you would probably have to take apart your ipod and rewire it and all of that complicated stuff that makes my head hurt. 

    This is very interesting! If you owned a field where you host airsoft battles you could require the participants to wear a jacket with your idea/invention that is linked back to a computer with an operator ready to call 'Hits'. That way nobody can cheat. The only downside i see is the fact that the slightest bump could make the operator think your hit. maybe you could tweak it. But overall nice!

    3 replies

    Just an 'add on' to my last comment: this could actually be used in real war combat. If a team is going for stealth they could use this watch to reveal enemy position without words. (you know like : Enemy, five o'clock)

    They do have microphones that receive and send sounds through your ear bones, eliminating almost any sound necessary to communicate. As for this in combat, it'd had to be wireless, and thus giving out signals. Not very stealthy.

    true but maybe if you used ELF (extremely low frequencies) but that can be pick up too so maybe not

    I could totally see this being used in conjunction with turn tables. If you look at a lot of the scratch videos on youtube(http://www.youtube.com/watch?v=ja9F63jeGOU&feature=related) there is often a computerized version of the record shown, which is much like the clock in the videos. It is used as a place to gauge where the sounds begin on the fly without having to memorize where they are on the record. It would be awesome if you could come up with something like this.

    wow, i actually woke up this morning thinking: "i need a fabric potentiometer"* and here it is! you rock! :D

    • not being facetious or sarcastic, i really did!

    Very good as for me. Combine it with your earlier tilt sensor and you're not far away from an input device with scrolling.

    The thought that instantly occurs to me looking at this is that it would make a good "tactile watch" for the blind who don't want to use speaking watches (or deaf-blind). You could add a pager motor or other tiny tactile feedback device that vibrates when you touch the part on the ring that corresponds to the current minute- not sure how you'd do hours, perhaps have a "mode" button, or two rings. As it is it's a nice demonstration of concept, but doesn't actually do much.

    7 replies

    That's a good idea,but I think there are Braille watches out there.

    I'm not sure that this example would make a good tactile watch, since it is an input device. But i really like your idea of the tactile watch and you've already got me thinking about possible solutions. Thanks

    if you use this watch as the input to a comparator circuit that compares what you input on the dial with the current time supplied by a regular watch, when they match up, output a pulse that the user could feel on their wrist. maybe add two other touce buttons to select minutes and hours.

    if you use this watch as the input to a comparator circuit that compares what you input on the dial with the current time supplied by a regular watch, when they match up, output a pulse that the user could feel on their wrist.

    Yep, that's what I meant- it would be like feeling the position of the hands on a regular watch face, when you touch the position of the hand then the pager motor vibrates. I probably didn't make that completely clear in my original reply, though.

    Bonus points if you reverse-engineer the headphone mounted controls on the new iPod shuffle so you can use this as controls for it :)

    Yes, funny, this was also an idea i had, after thinking about your initial comment. there could be two resistive rings, one for hours, one for minutes. when the conductive finger-tip makes contact at the actual position of the current time, the bracelet could vibrate to indicate this. one would have to go through this procedure twice to get the exact hour and minute, but on the other hand it can be useful, if the hour is only known, then only the minutes need to be checked. i'm just about to post an update video to show the possibility of eliminating the conductive finger-tip.

    Nice thread developing here... I don't like the idea of a motor- solid-state is where it's at! How about instead, put an electrostim (from a TENS circuit) into the fingertip from the conductive dial. This way, the haptics would be right. Almost as good, in fact, as the watches that the blind already use, which simply have a hinged glass so you can feel where the hands are...

    You could use one ring and one motor, with two vibrations for minutes and one for hours. Your project looks very interesting I think I might have to finally get some conductive fabric.