resistor suggestion please

[lukkbox]

hello

i am making a small circuit composed of 4 AA rechargeable batteries in a box with an on/off switch and one red and one black wire

can you please suggest a type/spec of resistor to put into this circuit that will generate heat above 40c and below 70c

thanks in advance for any suggestions/explanations

 

[blueroomelectronics]

Use heater wire and you'll need a feedback circuit with a thermometer or some form of temperature control (in the old day a bimetal switch was popular)
**broken link removed**

Hope you don't expect 2800mAh batteries to last very long.

 

[lukkbox]

in the video on this page > Warmthru - Heated Socks at 1:25 she slips a flexible film thin heating pad into the sock

where is the best place i can get one of these please?

 

[Noggin]

I think you can get them here

 

[lukkbox]

I think you can get them here

nah they sell every part of that kit individually EXCEPT the element lol

dont think i would want to pay their prices anyways, seems ridiculous

b*st*rds

 

[ash20]

u know what?? if you simply use thick socks and wear light shoes all day, i dont think you will even need a circuit to keep your feet warm!!!

 

[ash20]

else,
Coil heaters are your required heating elements that are formed from straight, uncoiled segments of heating cable. Forming straight cables into patterns increases the surface area and heat transfer capability, but also requires increased energy and watt density. Mostly coil heaters and cable heaters operate on AC voltages. Some include a grounding wire or provide distributed wattage arrangements to concentrate heat distribution.
There are a variety of shapes and sizes for coil heaters like straight, square, rectangular, round, coiled etc. Some devices encase the coil or cable to protect it from damage and to maximize heat transfer.
Coil heaters are made from several different types of materials and typically include insulation. Sleeve, sheath, and jacket materials include aluminum, brass, copper, iron, nickel alloy, steel, and stainless steel. Insulation materials include ceramics, mica, minerals, and fiberglass. Mica is highly resistant to acids while fiberglass is impervious to many caustics. Clamping straps provide additional protection for coils and connections.

 

[lukkbox]

u know what?? if you simply use thick socks and wear light shoes all day, i dont think you will even need a circuit to keep your feet warm!!!

good advice

i got great 4 season wool socks, well insulated boots and probably the best layering clothing system available, every part of me is nice and toasty warm except my toes

i can cure it myself by going for a brief walk or a jog while fishing but the noise on the bank scares the fish away so whats the point in being there? lol

the problem i have is that i am sitting for prolonged periods through the night so my circulation suffers, hence no bloodlfow, hence cold toes

and cold toes are the only thing that can ever make me miserable and when im miserable i dont wanna be fishin so i gotta heat em up!

they sell these kits through retail etc for like £100+ but im sure i can do better for cheaper

where can i get etched foil flexible heaters for cheap guys?

 

[lukkbox]

else,
Coil heaters are your required heating elements that are formed from straight, uncoiled segments of heating cable. Forming straight cables into patterns increases the surface area and heat transfer capability, but also requires increased energy and watt density. Mostly coil heaters and cable heaters operate on AC voltages. Some include a grounding wire or provide distributed wattage arrangements to concentrate heat distribution.
There are a variety of shapes and sizes for coil heaters like straight, square, rectangular, round, coiled etc. Some devices encase the coil or cable to protect it from damage and to maximize heat transfer.
Coil heaters are made from several different types of materials and typically include insulation. Sleeve, sheath, and jacket materials include aluminum, brass, copper, iron, nickel alloy, steel, and stainless steel. Insulation materials include ceramics, mica, minerals, and fiberglass. Mica is highly resistant to acids while fiberglass is impervious to many caustics. Clamping straps provide additional protection for coils and connections.

i think what i need is a foil etched flat heating element that can slip under the sock or insole

 

[ash20]

well for heating element, you can stick "Resistance Heating Wire" to aluminium foil and make a shape similar to that video.. for more details on the wire refer https://www.electro-tech-online.com/custompdfs/2010/12/NI60.pdf

stick with a conducting solution easily available in market and then when it warms, it gives warmth to aluminium foil thus evenly spreading the heat and then you enjoy the warmth...

 

[lukkbox]

well for heating element, you can stick "Resistance Heating Wire" to aluminium foil and make a shape similar to that video.. for more details on the wire refer https://www.electro-tech-online.com/custompdfs/2010/12/NI60-1.pdf

stick with a conducting solution easily available in market and then when it warms, it gives warmth to aluminium foil thus evenly spreading the heat and then you enjoy the warmth...

i like the way your thinking fella!

so if i'm running 4 x AA's at 4.8volts total how long a peice of this wire do i need to acheive say 60-70 degrees C? i guess it depends on the resistance of the wire?

sorry for all the questions i know they must seem idiotic, i am an electrical idiot, but i do get a kick out of making my own stuff!

is it also important to not let the wire touch itself?

how do i build this thing?

 

[kinarfi]

If I were going to make one of these, I'd start with the wire mentioned earlier, https://www.electro-tech-online.com/custompdfs/2010/12/NI60-2.pdf, and some Clearmask paint protector, because I have some. Lay out a piece of the tape and then lay the wire on it and then fold some more tape over it with the lead coming out. The Clearmask should stand up to all the walking you want to do and keep you from feeling the wires under you foot. I have no idea how much wire to use, suggest you shoot for about .7 watts based on the following,
**broken link removed**
Good luck, let me know how it comes out
Kinarfi
Did a few calculations, using 30 ga wire,$10.00 for 50', you would need 4.3 feet of wire folded back & forth on your tape, maybe 3" by 4"