E-textiles EMC/FCC and durability issues

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In summary, it is unclear if FCC regulations will apply to a keyboard that is sewn into a shirt and uses normal but very thin pushbuttons. If shielding is needed, then it may be possible to do it by adding conductive fabric or paint over and under the conductive wires.
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kb_designer
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I am trying to build a keyboard sewn into a shirt and I wonder if I need to worry about EMC/FCC issues with the conductive thread to the keys? For each key I use a normal (but very thin) pushbutton, the wire length to the arduino controller will be no more than 150 mm and I will use DC 3-5v. Because I debounce the signals from the buttons I assume that EMC won't be an issue for my stuff, but what about other devices?

It will most likely be a low volume product (no more than 100 units) and I don't think I can afford to do proper EMC/FCC certification so my plan is to shield everything that needs shielding and then keep my fingers crossed that the FCC won't show up at my door.

If shielding is needed then I think I can do it by adding conductive fabric or paint over and under the conductive wires.

1. How big is the risk that my device will effect other devices and thus potentially anger the FCC?
2. How big is the risk that my device will be effected despite debouncing?
3. If I have a "hole" in my shielding that is 1-2mm wide and 150mm long will that allow RF signals do go through and cause EMC/FCC issues?
4. What is the most durable choice of material for the conductive thread? From what I've read it is supposed to be stainless steel fibers but perhaps there is a better choice? Clothing means it will go through lots and lots of flexing and stretching.
 
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kb_designer said:
3. If I have a "hole" in my shielding that is 1-2mm wide and 150mm long will that allow RF signals do go through and cause EMC/FCC issues?
A slot with longest linear dimension, L = 150mm, in a shield is a perfect slot antenna for EM waves with wavelength λ = 2L = 300mm, or 1 GHz. In other words, the slot will pass anything above 1 GHz without attenuation. Below 1 GHz, the Shield Effectiveness (SE) increases with 20dB per decade according to SE = 20 log (λ/2L).

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Source: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CCwQFjAA&url=http%3A%2F%2Fwww.lairdtech.com%2FWorkArea%2Flinkit.aspx%3FLinkIdentifier%3Did%26ItemID%3D3400&ei=Bt7VUbrkLaGn4gSdmYCQCA&usg=AFQjCNGcU7gzJdO6s7PK9BOV51BBuJVLYA&sig2=ZrtyPU28KJ3hLtPV2Yk1lQ&bvm=bv.48705608,d.bGE [pdf]
 
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FAQ: E-textiles EMC/FCC and durability issues

1. What is an E-textile?

An E-textile is a fabric or garment that incorporates electronic components, such as sensors, conductive threads, or microcontrollers, to perform a specific function.

2. What is EMC/FCC and why is it important for E-textiles?

EMC (Electromagnetic Compatibility) and FCC (Federal Communications Commission) are standards that regulate the electromagnetic emissions and susceptibility of electronic devices. It is important for E-textiles to meet these standards to ensure they do not interfere with other electronic devices and to protect the wearer from potential health risks.

3. How do E-textiles undergo EMC/FCC testing?

E-textiles undergo EMC/FCC testing by exposing them to various electromagnetic fields and measuring their emissions and susceptibility. This can be done in a laboratory setting using specialized equipment.

4. What are some common durability issues with E-textiles?

Some common durability issues with E-textiles include wear and tear on the conductive threads or components, damage from washing or drying, and issues with connectivity or functionality over time.

5. How can E-textiles be made more durable?

E-textiles can be made more durable by using high-quality materials, reinforcing critical areas with additional stitching or shielding, and following proper care instructions for washing and drying. Regular testing and maintenance can also help to identify and address any potential durability issues.

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