Credits: Mika Satomi
Materials: conductive yarn, normal yarn, marble/stone, beads, conductive thread, conductive fabric
Dimensions: 12cm x 3cm x 1cm
Description: When you knit/crochet with conductive yarn, it changes the resistance when it is stretched.
So, I thought of making an accelerometer with same principle. The weight at the end pulls and stretches the crochet or knitted structure as it gets accelerated. It works the best when this sensor (more of an object) is swung around like hammer throwing.
For the sample book, it is made with crochet technique. The first round starts with single crochet loop of 3, 1st round, add 1 on every stitch, and build until 1/4 of the weight object height (for samples, I used marbles or small stones). You can also use bigger and heavier weight, which will make the sensor more responsive. Continue with double crochet with extra 1 stitch space in between to achieve net like structure. at the 3/4th of the object height, change into single crochet and decrease the stitch number to follow the object shape. then continue with single stitch to build up the tube, change into conductive yarn and continue the tube. This part act as stretch sensor. when you build enough height of stretch sensor, switch with normal yarn and finish off as you reach the desired object size. Make connections from both top and bottom edge of the stretch sensor part with conductive thread to the top of the Accelerometer. Use beads to isolate the bottom connection thread. Connect the end of the conductive thread with small piece of conductive fabric so you can connect with the rest of the circuit or with LED sensor checker.
Supporting materials: Additionally you can build LED sensor checker to visualize the effect of the sensor. The checker includes LED, conductive thread, Neoprene (or any non conductive fabric) 3V coin cell battery and snaps. Please see the construction plan.