New Textiles 2010

Re-imagining the fundamental yarns of a textile provides an opportunity to think about embedded intent and actuation schemes. We have seen in class materials that sense and communicate, but what about textiles that 'do' ? Nitinol wire has traditionally been the first approach to this question, but large switching times and required currents continue to be obstacles to adoption. Here we explore the first steps of incorporating magnetic components as an eventual alternative.

EMY2: Conductive thread was dip coated in a polymerizing silicone rubber and was removed after 6,7, and 8 minutes respectively. This was done to determine whether this could be a viable option to replace the coated copper wire. This has been ruled out for the time being.

Cotton balls were unrolled and laid on top of each other with ends fanned out. The cotton was then hand spun by twisting an S twist. Copper wire was then twisted as a Z twist and coiled ~120 times every few centimeters. The entire piece has a resistance of less than 30 ohms. The entire yarn is insulated and is only conductive end to end.

With its short fibers and ease of untwisting, cotton proved challenging to use. We hypothesize that the electromagnetic would be stronger if the coils were around a ferromagnetic material rather than an air core. Fortunately our work with steel wool puts us in a good position to test this theory within the next iteration. Incorporating permanent magnets should be delayed until order of magnitude estimates are completed to determine sizing.

Two spun strands were twisted, one entirely cotton and the other cotton, alternating with steel wool or steel wool with small magnet. After being twisted together, additional cotton and steel wool were added around both strands to help with cohesion and keeping the magnets in place.

Cotton balls were unrolled and laid on top of each other with ends fanned out. The cotton was then hand spun by twisting an S twist. Copper wire was then twisted as a Z twist and coiled ~120 times every few centimeters.

Note that a .5 T magnet did interact with the electomagnet enough to pick up the end when the current through the yarn was approximately 600 mA.

These yarns seem to have a mind of their own!

• 6 in. yarn incorporating all above materials

Motivation Re-imagining the fundamental yarns of a textile provides an opportunity to think about embedded intent and actuation schemes. We have seen in class materials that sense and communicate, but what about textiles that 'do'? Nitinol wire has traditionally been the first approach to this question, but large switching times and required currents continue to be obstacles to adoption. Here we explore the first steps of incorporating magnetic components as an eventual alternative.

Two spun strands were twisted, one entirely cotton and the other cotton, alternating with steel wool or steel wool with small magnet.

Electromagnetic Yarn: Prototype 1 (EMY1) Features:

Electromagnetic Yarn: Prototype 2 (EMY2) Features:

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Data

Measure and report the following properties (if they are relevant for your yarn): diameter (micrometers) total length of yarn (meters or yards) ply fiber length (millimeters) twist direction twist (turns per inch) conductivity (ohms per centimeter or ohms per inch)

Bonus points for measuring any of the following properties and explaining how you did so: denier or tex yarn size tenacity elongation elastic recovery absorbency

MY: two ___ were twisted, one entirely cotton and the other cotton, alternating with steel wool or steel wool with small magnet.

EMY 1: Cotton balls were unrolled and laid on top of each other with ends fanned out. The cotton was then hand spun by twisting a _ twist. Copper wire was then twisted as a __ twist and coiled every few centimeters.

EMY2:

Conductive thread was dip coated in a polymerizing silicone rubber and was removed after 6,7, and 8 minutes respectively. Techniques from MY and EMY1 were combined, unfortunately unsuccessfully. THe magnets selected were too strong and the yarn would not remain in the desired static position.

Magnetic Yarn (MY)Features:

[+Electromagnetic Yarn: Prototype 1 (EMY1)Features:+ ]

Electromagnetic Yarn: Prototype 2 (EMY2)Features:

Datat

• In development:
  • 6 in. yarn incorporating materials
  • 36 in. silicone dip-coated conductive thread

These yarns seems to have a mind of their own!

• 6 in yarn incorporating materials
• 36 in silicone dip-coated conductive thread

• Cotton, Steel Fibers, and Neodymium Magnets

• Electromagnets lend themselves well to the form factor of yarn and this 23 inch cord featuring 21 "beads" of coiled copper will behave as one.

Features: Electromagnetic Yarn: Prototype 2 (EMY2)

• Cotton, Steel Fibers, Coated Copper Wire, and Neodymium Magnets
• Conceptually bunching and unbunching possible
• In development

-6 in yarn incorporating materials -36 in silicone dip-coated conductive thread

• Over 2500 coils with area <20mm^2!
• Electromagnets can be re-oriented to direct field lines conveniently.
• Copper wire allows high current without burning up
• Actuation (bunching) may be possible

• Electromagnets lend thems selves well to the form factor of yarn and this 23 inch cord featuring 21 "beads" of coiled copper will behave as one.
• Over 2500 coils

Yarn

Magnetic Yarn

These yarns seems to have a mind of their own.

http://newtextiles.media.mit.edu/uploads/S/Smaller1.jpg

Operating Instructions

1. Magnetic Yarn
2. Electromagnetic Yarn: Prototype 1
3. Electromagnetic Yarn: Prototype 2

Features: Magnetic Yarn (MY)

• Cotton, Steel Fibers, and Neodynium Magnets
• Over the 18in length, the yarn is insulating. However because of 1 inch conductive (10-100 ohm) patches, the yarn's resistance is sensitive to posture and internal connection.
• Can be attached to any ferromagnetic surface (like your refrigerator)

Features: Electromagnetic Yarn: Prototype 1 (EMY1)

• Cotton, and Coated Copper Wire
• Over the 18in length, the yarn is insulating. However because of 1 inch conductive (10-100 ohm) patches, the yarn's resistance is sensitive to posture and internal connection.
• Can be attached to any ferromagnetic surface (like your refrigerator)

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Role of Conductive Fabrics

In this project we take advantage of textiles as optimum engineering materials that provide integrated functionality, parallel construction leading to robustness, and user friendly softness.

Circuit http://newtextiles.media.mit.edu/uploads/S/Smaller2.jpg

Construction

The body of the purse is regular yarn crocheted in the round followed by a rim of a crocheted strip of stretch conductive yarn. The two are bound together with a crochet stitch. The rim has a resistance of 300 kilo-ohms unstretched and 50 ohms stretched. In this way it acts as a stretch sensor. The lid is sewn from conducting and non conducting fabrics with a neoprene battery holder embedded. When a conductive thread was used (as in connecting the battery terminal to the rest of the circuit), at least one other path was also sewn. This ensures that even if the purse experiences a small tear, the circuit may still survive.

Opportunities for Improvement

The movement of the lid was neglected in the design, so the exposed LED mounts may short circuit with the conductive parts of the lid when moved. This could be fixed with a simple nonconductive covering over the mounts. Also since the LED is sewn onto the same fabric as the rest of the lid, the LED may tilt up as opposed to down into the purse. One solution might be pushing the LED farther into the purse and bending it further into the purse before sewing down the mounts. Finally, the lid requires an inside hook to clasp the purse closed during transit.

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