Liz0905: what do you mean?
250W is crazily high and will burn you. 1W will do nothing. So 10W is about right as a starting point for designing a warmer like this. Perhaps it should be 20W, perhaps not, you need to experiment. Remember a lot of soldering irons use 40W or less...
BabyGeezer: when one is learning, you shouldn't have to apologize for ignorance - the whole point about learning something is because we are ignorant to the facts surrounding the topic !
the folks here are very understanding and patient enough if you can respond to whatever further clarifications they request.
that's probably the other way around - you (ideally) want the 10W heating element.
just to clarify from your earlier post; this --> https://www.sparkfun.com/products/10213 does not "provide" the current - it controls it - the current comes from the power supply unit. (battery, wall-wart, etc.)
Thank you very much!
MarkT: 250W is crazily high and will burn you. 1W will do nothing. So 10W is about right as a starting point for designing a warmer like this. Perhaps it should be 20W, perhaps not, you need to experiment. Remember a lot of soldering irons use 40W or less...
Ok, thank you. so for my purpose I can use five heaters with a power of 10W. If I want to power an Arduino with an external battery, Will the next battery be enough for me
And would I need a transistor for each element? Suppose I use all the heaters simultaneously. Should I connect the heaters in a circuit? So that they are independent of each other
What are the gloves to be used for - I suspect that the insulation is as important as the heat source.
Will the next battery be enough for me
No.
so for my purpose I can use five heaters with a power of 10W.
That is 50W, this requires a current of about 5.5A. That looks way too much for that battery, even if it was not then at 1.2Ah it would last at the most 13 minuets and probably not more than 8 or 9 minuets in practice.
I would have thought 50W in a glove is way too much. What is the purpose of this glove? It makes a big difference. My 50W soldering iron is quite big, you can solder with a 25W iron or even a 15W one.
ChrisTenone: What are the gloves to be used for - I suspect that the insulation is as important as the heat source.
I want to measure the temperature of a finger and warm it if the temperature falls below a certain threshold
Grumpy_Mike: No. That is 50W, this requires a current of about 5.5A. That looks way too much for that battery, even if it was not then at 1.2Ah it would last at the most 13 minuets and probably not more than 8 or 9 minuets in practice.
I would have thought 50W in a glove is way too much. What is the purpose of this glove? It makes a big difference. My 50W soldering iron is quite big, you can solder with a 25W iron or even a 15W one.
ok i got it. what about those:
Hi,
The
is designed to always be at 60 °C, much too hot for skin.
I did some work with PTC heaters a few years back and they are great for constant temperature, however I've not seen any where the transition (control) temperature is low enough to be useful for contact with humans.
I've not been following closely but have you looked at flat silicone heaters?
JohnRob: Hi,
The is designed to always be at 60 °C, much too hot for skin.
I did some work with PTC heaters a few years back and they are great for constant temperature, however I've not seen any where the transition (control) temperature is low enough to be useful for contact with humans.
I've not been following closely but have you looked at flat silicone heaters?
Because I'm really new to the whole thing, I did not even know which way to look
HI,
This is not the place you would normally purchase a flat heater but it gives you an idea.
They could also be flat Kapton heaters.
For a practical understanding of watts and heat look for one of these "GE 4-Watt Nightlight Incandescent Light Bulb". You can hold it in your hand and get a "feel" of what 4 watts will be like.
I guess that these heated gloves might be for a motorcycle.
In which case there is no power supply problem.
Commercial products are freely available - why not investigate these?
Allan
allanhurst: I guess that these heated gloves might be for a motorcycle.
In which case there is no power supply problem.
Commercial products are freely available - why not investigate these?
Allan
The project is part of my studies and one of the goals is to create something that does not exist something that is exactly the same
create something that does not exist something that is exactly the same
??
They do exist, and have been developed over many years.
Do you have a much better approach?
A
allanhurst: ??
They do exist, and have been developed over many years.
Do you have a much better approach?
A
Of course they exist and I studied them, the goal is to use components that are not used in warming gloves available in the market
All such gloves use resistive elements of some sort - normally NiChrome wire, but any power dissipating element would do .....
eg a Pentium processor.
NiCr is cheap and effective.
For temperature sensing a thermistor is the obvious device.
Allan
allanhurst: ... eg a Pentium processor.
Cool! You could recycle old, unwanted computers as hand warmers.
allanhurst: ... For temperature sensing a thermistor is the obvious device.
Wouldn't a device like a TMP36 (such as this one) be even simpler to use?
TMP36...
Sure,
There's a hundred ways to skin a cat.
I bought 100 10k thermistors for £1. Though I don't intend to control 50 pairs of gloves.
You don't need an arduino for this job - a simple bit of analog will do.
Ramp generator ( 555? ) , comparator , reference volts source.and power switch device
Allan
Of course you are correct - that would certainly be the most cost-efficient to build heated gloves. But that isn't the theme here. It seems our OP wants to make something DIY with parts on hand. And Arduino control has easy appeal. But with 50-250 watts of power inside an insulated glove, I wonder what it's actual use would be.
The ancient LM10, designed by Bob Widlar, would be ideal for this job.....
but I share your puzzlement over the application.
Any help.OP?
Allan
MarkT:
250W is crazily high and will burn you.
1W will do nothing.
So 10W is about right as a starting point for designing a warmer like this. Perhaps it should be 20W,
perhaps not, you need to experiment. Remember a lot of soldering irons use 40W or less…
I’m intrigued by the project and wanted to see what I could make and get a feel for what wattage a glove heater might need to be. I etched a heater from polyimide film using material that I requested for free from Dupont’s website:
The heater I made was this spiral thingie (see picture below) that I then cut up to be one long heater. It has a resistance of 3.5 ohms. It is just long enough to wrap around each of five fingers.
I’m powering it with an old weedeater battery that limits current to 1.5A. The battery is 20V so I’m using a buck converter to take it down to 6V.
To test I wore a thin cotton glove and then wrapped one finger with the heater and turned it on. I could feel it warm up quickly but didn’t get too hot. If I put this assembly inside of a winter glove I think it would work even better. At 9 watts it’s just right for my tastes.
A thought I had was to adhere the polyimide heater to the glove with thermal glue and then spray it with plasti-dip to give it a rubber coating and make it more water resistant. It would sort of be a hybrid of two different flexible heaters.
