I need a heating element that can be controlled on/off by the Uc and that can be small, only a few cm wide.Where can I get one, and how should I choose which one to get?
Any electric heating element can be controlled by a UC. Generally you would use a Power MOSFET to turn it on and off. Nichrome wire is much less than 1 cm wide.
How much heat do you need?
stef100111:
I need a heating element that can be controlled on/off by the Uc and that can be small, only a few cm wide.Where can I get one, and how should I choose which one to get?
simple to calculate.
how much heat do you need ?
if it is an enclosure, what is the heat loss of the enclosure and what is the heat gain ?
then all you need to figure out is the amount of energy you need to add to get where you want to be.
then, figure out your power source. heat will take lots and lots of power.
since most heaters are simple resistive circuits, all you need to do is to power them on and off so a simple FET control.
This heating element is necessary to lay on a roof to melt snow and ice while covered by it, at a lowest temperature of -25 degrees Celsius. Wondering what can melt the snow and ice buildup without any risk of setting the asphalt shingles on fire (or melt). How would that look? I don't know much on this unfortunately, this is my first time working with any type of diy heater. Power source is a standard American power socket. Where could I get the said transistors?
Thanks for any help given, I'm going to need it.
Why use an Arduino? Snow melters UL-certified for roof use are readily available on the commercial market.
Playing with 120VAC is not newbie stuff.
It needs to be activated when a certain weight of snow and ice is reached on the roof.
I should also note this is on a small scale and not on a full scale, it will be used on a small scale for a engineering fair at my school.
same wire/heater. add weight sensor to turn it on.
Can I maybe have links to guides on how to link this stuff and more importantly exactly what I will need for it?
?
Shameless bump. Need info.
You need to provide more information. How big is the small scale? Are you looking at a model roof area of say 600 x 600mm? What is the construction? Where is the demo going to be held (inside, outside, temperature)? How do you plan to apply the ice?
To come even close to what you want we need to know these things. Then we need to know how you will be powering the heater.
A roof with a couple of inches of ice or snow at -25 will require a considerable amount of power (heat) to melt it. You will need to be able to spread the heat. Nichrome wire will need to be very long to be able to cover the area in a back and forth pattern so as to get gentle heat and not burn the roof. This means either a lot of parallel pieces or feeding with a higher voltage.
Google snow melters as mentioned by Tylernt.
Weedpharma
Just need a square pattern of 6 inches on each side, total 2 feet of space to be covered. Asphalt shingles, inside. I don't need ice to be applied necessarily, but a temperature of about 100 degrees Fahrenheit should be fine for demonstration. I am not totally sure on the source of power, but can that be passed through the Arduino? How is a circuit with the wire coming from the Arduino going to look like? I really have no idea, and need guidance on the visualization and what I need to make this work as I have no experience with this quite unfortunately, and it needs to be done... I really appreciate any help, as I am lost.
You can get water pipe heat trace wiring which has a built in thermostat.
stef100111:
Just need a square pattern of 6 inches on each side, total 2 feet of space to be covered. Asphalt shingles, inside. I don't need ice to be applied necessarily, but a temperature of about 100 degrees Fahrenheit should be fine for demonstration. I am not totally sure on the source of power, but can that be passed through the Arduino? How is a circuit with the wire coming from the Arduino going to look like? I really have no idea, and need guidance on the visualization and what I need to make this work as I have no experience with this quite unfortunately, and it needs to be done... I really appreciate any help, as I am lost.
If you use nichrome wire, you need to work out how long and what power supply you will use.
Have you sourced the wire? How will you fix it to the roof? How will the heat be spread? You need to be able to spread the heat so you do not just get narrow hot strips.
Let's assume that 100 watts will do and you have a 12volt supply. It would need to be able to supply at least 9 amps. This is much too much for an IO pin so would best be handled by a relay or power mosfet. You will need a transistor to switch the relay for one able to carry that much current.
Remember that the power will cause the wire to heat so make sure you have done calculations to make sure it does not overheat and cause a fire.
Find your wire, find your power supply and let us know their specifications. We can then do some calculations to help you.
Do some research on commercial units to find out how they do it.
DO NOT use mains power on the nichrome wire.
Weedpharma
all you need to do is to change the phase. the energy needed is to change ice to water 100° is huge.
I think the problem you have with nichrome is that when in contact with ice or water, it will have a different section that is not, so the one section will get hot, very hot, glowing red hot, while 95% is not hot.
in other words, the sections in contact will have one resistance, while the open air will have a different resistance. all the power will travel easily through the cold wire and the resistance of the hot wire will cause it to heat more.
better to get a section of actual roof melt wire.
maybe pulse the nichrome so the heat can dissipate.
maybe have a pair of mains and lots of cross connects that are shorter ?
it sure is simple enough to test. buy a roll and get some ice out of the ice box.
As a beginner this is becoming more in depth and difficult than I was expecting. Ignorance is bliss, that's for sure. I may change my project rather to an alarm that is set off by the weight instead, to be set off when there is too much snow. Thanks for the guidance, I'll report back on whether I have to stick to this idea or not.
Here's a doable one. How about a fan that blows the snow off when it's too white. Detecting light levels is quite easy. Put a light dependent diode behind a lense that is focused on the roof and you'll easily be able to detect when it's covered with snow.
turning on a fan is easy.