This sensor senses stroke in multiple directions. Using a technique similar to that for carpet making, conductive threads are distributed in patches and patches are connected together on the back side. Within the patches the threads are connected and when the threads of one patch make contact with the threads of another patch, this can be detected as if it were a digital switch.

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The basic functionality of this sensor is that of a contact switch. Pieces of a Silver Plated Nylon 117/17 2ply conductive thread are sewn in and out of neoprene, similar to the hooked rug technique. The friction of the thread sewn into the neoprene is enough to keep it from coming loose, even when stroked repeatedly.

a) The simplest example of the stroke sensor is to have a row of conductive threads that are connected to one another on the reverse side, by stitching them through a strip of conductive fabric. When stroked flat, these threads are long enough to make contact with another piece of conductive fabric mounted on the top of the sensor. Closing the switch.

b) Instead of being able to directly connect, the two sides of the switch are distanced from one another and an additional row of conductive threads that are not bound to either side of the switch are inserted in between. This forces the stroker to stroke a greater surface, flattening more threads over a larger surface, in order to bridge the distance and make the connection.

c) Sees the introduction of non-conductive or resistive threads between the conductive connections. In the case of non-conducive threads these tend to create an isolating barrier when stroked, making contact difficult. By using resistive threads in place of non-conductive I expect it will be possible to detect the pressure applied while stroking, in addition to the stroke direction.

The first photo shows the method of sewing the conductive thread in and out of the neoprene. You can use thread up to four pieces of thread through the same hole in one go.
The second photos shows an early prototype that uses thicker conductive thread from Lame Life Saver. At first I thought this thread would work better because it was softer and thicker, but it turned out that after only a few strokes, this thread fray incredibly and becomes soft and curly. I’m sure there will be other uses for this property, but for the stroke sensor the 117/17 2 ply thread really works best.

Example of a sheep stroke sensor that can detect stroking in two directions.

Video of example c – two conductive thread patches with resistive threads in between. Strength/intensity/pressure of stroke can be detected as well as direction. Though this sensor has only two contact points and can not detect direction.

Another video of example c.

Video of rather unsuccessful sheep stroke sensor example. The non-conductive threads between the conductive patches of thread make it hard to make contact.

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