This is a step by step showing how to sew e-textiles components onto fabric. Here is an adjustable strap.
Step 1: Draw Out Your Circuit
Decide on the shape of your e-textiles product (here is a wrist band). Your will also need to have tested your components in a hard circuit to make sure it works before making this soft circuit. Next decide where you want your components to be and draw out where the circuit will be (ie where you will sew with your conductive thread). I have colour coded this drawing so you can see where I have sewn. The pink line is from the positive point of the Igloo to the positive of the battery holder. The Purple line from the negative of the Igloo and goes along the strap to the Velcro and across to the negative of the battery holder. I have programmed the Igloo using points C0 and B4 and hence the orange lines from these points to the positives on the LED's and finally the yellow lines from the negatives on the Igloo to the negatives on the LEDs. It is very important not to cross over the conductive thread as this may cause your circuit to short circuit - hence drawing a diagram of your intended layout is important.
Step 2: Cut Out Your Fabric Piece(s) for Your E-textiles Product
Decide on the shape and size of your e-textiles product and draw up a flat pattern. Cut out a flat pattern of your product (using paper is fine). Pin your pattern to your fabric to hold it in place before cutting it out. Cut out with scissors. To make a strap you will need to cut out the pattern twice.
Step 3: Attach Larger Components
From your diagram in step one you may find there are connection points that you wont be using. On one of the fabric pieces secure the components in place by sewing these connection points using non-conductive thread - shown here in orange thread.
Step 4: Sew With Conductive Thread
Using your diagram to help you, sew on components with conductive thread, keep your sewing neat and tight, particularly at the connection points to ensure a good connection. Remember to finish off (with a few stitches in the same spot) at each connection point (ie the stitching should end a one connection point and start a fresh at the other connection point(s) on the component), ensure this is done neatly, cutting off any ends (this is so as not to create a short circuit). Remember to keep to your diagram and don't cross over your stitching lines. Always us a running stitch when sewing with conductive thread.
Step 5: Sewing on the Press Studs (for Wrist Band)
The purple highlighted lines on my diagram are where the conductive thread going to the press studs. At the top of the wrist band the conductive thread should be sewn to one connection point of the press stud only and only on one side - I have done the left side - so your circuit will go through 1 set of press studs only (in this case the left). Remember to sew the press stud top and bottom on opposite sides of the fabric. I have fixed the press stud top to the top underside of the band and a few press stud bottoms (to make the strap adjustable) to the bottom of the band on the top of the fabric. Remember to finish off your thread at each connection point on the press stud (see pictures) and ensure each press stud bottom on the left side is part of the circuit (so the strap can be adjusted). You can fix the other points on the left press studs and all the press studs on the right with non conductive thread.
Step 6: Add a Panel at the Back (wrist Band Only)
Take the second piece of fabric you have cut out - pictured in two pieces but one is better - and trim it so it fits under your top press studs. This will make your product look more aesthetically pleasing and cover any conductive thread stitches so the conductive thread and components do not come into contact (and short circuit the product) when the adjustable strap is on the tighter strap options. Sew this on around the edge with non conductive thread. This is a prototype only.