I've bought some silver condutive thread on ebay, but i start searching about the thread and i found that the thread will oxidize quickly unless i can isolate it. Some pages said that i could use fabric paints or puff paints but i can't find where i live (Lisbon, Portugal) so i thought i could use some clear nail polish, what do you think? My problem about nail polish is the alcohol in it, could the eletricity ignite the alcohol? I personally think that the alcohol will evaporate but im not sure. What do you guys think?
I doubt that the used solvent is alcohol, i go for acton or something similar.
The solvent will be gone after drying, no problem.
Electricity in the used range only produces sparks on shortcut, or on relay contacts.
The oxidation layer will insulate the silver just the same as your nail varnish. Oxidation is only a problem if you want to contact something to the thread.
Grumpy_Mike, Yes, the passivation layer will protect the silver from the oxidation, but its only 15% Ag, the other 85% i dont know what it is, do you think that the thread will be protected with only 15 % ?
TiagoPT:
About the oxidation, its not the oxidation that would isolate, but the passivation of silver.
Nope. Oxidation does not mean oxide.
Oxidation is the loss of electrons or an increase in oxidation state by a molecule, atom, or ion.
Silver is stable in pure air and water, but tarnishes when it is exposed to air or water containing ozone or hydrogen sulfide, the latter forming a black layer of silver sulfide.
Passivation, in physical chemistry and engineering, refers to a material becoming "passive," that is, being less affected by environmental factors such as air and water. Passivation involves a shielding outer-layer of base material, which can be applied as a microcoating, or oxidation which occurs spontaneously in nature. As a technique, passivation is the use of a light coat of a protective material, such as metal oxide, to create a shell against corrosion.
Whandall:
I think stainless material will be too rigid, but check it out.
No it's not, it is like a thick cotton, you can sew with it and is very flexible. The only snag is that it feels a bit rough to the touch as it has whiskers, which can short adjacent threads if they are too close. Don't go closer that 1/8". These whiskers are invisible to the naked eye but you can see them under a microscope.
i finally found a good place to buy the stainless stell thread, so i can move to the actual project, but this is my first project and i dont have any skills at this moment. Could you guys help me?
My project consists of a t-shirt with leds and a heartbeat sensor, when the heart beats the arduino flash some leds and when the heart rests it blinks other leds.
While the individual pins can sink or source 20mA there are restrictions on the collective total of the overall chip.
The data sheet says:-
Although each I/O port can sink more than the test conditions (20 mA at VCC = 5V, 10 mA at VCC = 3V) under steady state conditions (non-transient), the following must be observed:
ATmega48PA/88PA/168PA/328P:
1] The sum of all IOL, for ports C0 - C5, ADC7, ADC6 should not exceed 100 mA.
2] The sum of all IOL, for ports B0 - B5, D5 - D7, XTAL1, XTAL2 should not exceed 100 mA.
3] The sum of all IOL, for ports D0 - D4, RESET should not exceed 100 mA.
If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater than the listed test condition.
Although each I/O port can source more than the test conditions (20 mA at VCC = 5V, 10 mA at VCC = 3V) under steady state conditions (non-transient), the following must be observed:
ATmega48PA/88PA/168PA/328P:
1] The sum of all IOH, for ports C0 - C5, D0- D4, ADC7, RESET should not exceed 150 mA.
2] The sum of all IOH, for ports B0 - B5, D5 - D7, ADC6, XTAL1, XTAL2 should not exceed 150 mA.
If IIOH exceeds the test condition, VOH may exceed the related specification. Pins are not guaranteed to source current greater than the listed test condition.
Over and above that the limit on the Vcc pin is 200mA. So it is complex.