Capacitance is the ability of an object to store an electrical charge. In this tutorial we will design and weave textile sensors that respond to our bodies capacitance and use that electricity to complete a circuit.
In this tutorial you will learn basic weaving techniques via a plain weave construction and how to apply this technique to the creation of a textile sensor. By the end, you will understand how a textile antenna works and gain a basic understanding of capacitive sensing.
Step 1: What You Need
Step 2: Step 1: Warp the Loom
Step 3: Step 2: Draw Your Cartoon
In weaving, a cartoon is a drawing of your design, and it will be placed behind the warp. Another option is to draw it on the cardboard before warping your loom. Your cartoon will be used as a guide to follow while weaving, to show you where to change from regular to conductive yarn. The three rectangles in my design will be my conductive antennas.
Step 4: Step 3: Begin Weaving
Begin weaving. In this example, I will be using a basic plain weave. A plain weave is the simple structure of over-under-over-under. I will begin from the top, weaving the large section of acrylic yarn. I am doubling my yarn to speed up the weaving process.
Step 5: Step 4: Weave Your Conductive Antenna
Once I get to the conductive section, I switch to conductive yarn, weaving with a single strand this time. I follow my cartoon, and only weave in that area. When I am finished I should have two tails on the edge of the weaving.
Step 6: Step 5: Finish Weaving
When finished, move on to the next acrylic section, and weave around the conductive section. The yarn will build up around the antenna, and will eventually even out. Continue onto the next antenna. (I changed warp yarn colors).
Step 7: Step 6: Remove Weaving From Loom
Step 8: Connecting to the Board
Sew weaving to your piece of felt.
Step 9: Connecting to the Board: Step 1
With conductive thread, sew from your first antenna to one of the inputs on the capacitive sensing board. In this example, we are only using 3 inputs. And because we are stitching the connections we skip every other input on the board so that there is no chance of threads touching.
Step 10: Connecting to the Board: Step 2
Repeat with remaining antennas. Make sure not to cross your stitches as this will result in a short in your circuit. The back should look like this, with the knots kept short, so nothing is touching. Once knots are trimmed, seal with glue or nail polish.
Step 11: Connecting to the Board: Step 3
Now we will stitch our positive and negative connections from our power source. The ground input is labeled ‘GND’, and is on the same side of the board as our inputs. Twist the leads from the battery pack making a loop that we can sew in to. Stitch from ground, the black wire, to the ground pin on the board. Repeat on the positive side. The positive pin is located on the outputs side on the board as ‘VDD’.
Insert batteries into battery pack, and you are finished!