This sensor amounts to a variable resistor that changes value with length.

The advantages are:

• washable
• durable
• sewable
• standardized
• repeatable manufacturing process
• able to register non-differential changes

I use these in several applications, and after making many of them, it seemed like I should open up the practical information I have found and developed. If you use a lot of these, it is useful to have sensors with a defined range of min and max extensions, and fairly constant resistance values per rating so as not to require too much custom tuning for every sensor.

These are constantly improving… more to come.  More detail to come on the existing stuff too, just wanted to get this posted now....