One of the major obstacles when working with textile/conductive fabric electronics is connecting them to traditional electronic hardware and other elements. The following Instructable illustrates one way to overcome this drawback of such a fascinating emerging technology.
After reading this Instructable, you will be able to build your own female housing connector that is ideal for integrating conductive fabric sensors and other textile electronics with traditional electronics and wire.
These male headers can be used with conductive fabric/thread sensors such as these, as well as a great multitude of other applications:
-- Knit Stretch Sensor
-- Knit Touchpad
-- Conductive Thread Pressure Sensor
-- Conductive Fabric Bend Sensor
**Conductive thread female connectors can also be purchased pre-assembled or as a DIY kit.**
-- Pre-assembled Female Connector
-- DIY Female Connector Kit
Step 1: Materials and Tools
-- Female Crimping Terminals --> Can be purchased at Digikey
-- Terminal Housing --> Can be purchased at Digikey
-- Solid Core Wire (~20-28AWG)
-- Conductive Thread --> Can be purchased at Sparkfun or Lame LIfesaver
-- Fabric (aka what you want to sew conductive thread onto)
-- Female Connector Kit --> Can be purchased at Esty
-- Pre-assembled Female Connector - 5 pack --> Can be purchased at Esty
-- Soldering Iron
-- Wire Crimper
-- Wire stripper or scissors
-- Needle nose pliers
Step 2: Wire Loop End - Prepare Wire
First, we are going to want to start by making a wire loop at one end of our wire. This loop will be used to sew the connector to the fabric using conductive thread.
Strip and bend the solid core wire into a loop/question mark shape. The stripped section should be around 1/4". Unlike the male connector, getting this length right is more important because it is much harder to correct later on. You really want just enough exposed wire to complete the loop.
Step 3: Wire Loop End - Solder Wire Loop
Using solder and the soldering iron, solder the gap between the end of the wire and the base of the loop. Clip the wire approximately 1/4" to 1/2" from the wire loop depending on how long you want the wire to end up.
Tip: You don't want to use a whole lot of solder to do this. Too much solder could obstruct the needle from threading through the loop.
Step 4: Terminal End - Crimp Wire
Now, for the other end of the wire. We are going to use a crimp style terminal and wire crimper to make this end of the wire snap nicely into our housing.
First, strip off approximately 1/8" from the end of the wire opposite of the wire loop. Size does matter here. As you can see in the first picture below, you really only want this exposed bit to be roughly the same length as the second set of tabs on the terminal.
Place the new stripped end of the wire in the crimping terminal such that the insulation is slightly past the first set of tabs, as shown in the first picture below. The exposed wire should travel the length of the second set of tabs on the terminal.
Place wire and terminal into the wire crimper, selecting the correct wire gauge. Squeeze the wire crimper to crimp the terminal.
Inspect the crimp job to ensure the exposed wire is secured by the crimped second tabs of the terminal. Also, make sure the insulation has not been completely cut by the first set of tabs.
Step 5: Terminal End - Insert Terminal Into Housing
Next, insert the terminal into the housing by orienting the terminal with the open side facing the same side as the housing square holes. Push the terminal through until you hear a click as the third tab locks into the hole on the second row of the housing.
**Repeat steps 2-5 for each housing terminal position (In this example, there are three).**
Tip: To remove the terminal, simply use a pin, paper clip or some other small object to push the tab down. Then pull the terminal out.
Step 6: Application - Sewing the Connector
By this time, you've (hopefully) completed your female connector. Now you just have to learn how to integrate it into a soft circuit!
Using the conductive thread and needle, stitch the wire loop to the fabric starting from the top of the loop and working your way counter-clockwise around. When you reach the bottom of the loop, continue stitching leading away from the loop creating a trace. Continue stitching and leaving a trace as determined by your application (e.g. sensor, female header, etc.)
**Note: Using neoprene has an advantage over other fabrics because you are able to thread the needle into the fabric without having the thread exposed on the other side. This will insulate the thread.**
Again, repeat for each housing position.