Hi,
I want to put my arduino board uno in a greenhouse with very high humidity. In order to avoid water to condensate on it, I want to constantly heat it and put it in a plastic box. What would be the easiest way to generate some heat?
Is this a trick question?
A heating element.
What voltage do you have available?
What material is the enclosure made of?
What is the nominal temperature of the greenhouse?
adwsystems:
Is this a trick question?A heating element.
What voltage do you have available?
What material is the enclosure made of?
What is the nominal temperature of the greenhouse?
Not a trick question. I thought I could just plug in some resistors...
It's an Arduino Uno, so 3,3V and 5V.
Material of the enclosure is polycarbonate.
Greenhouse temperature can be from -15°C to 40°C.
Couple of wire wound resistors
Good smear of dielectric grease all over your board should eliminate the need for a heater..
phytopia:
Not a trick question. I thought I could just plug in some resistors...
It's an Arduino Uno, so 3,3V and 5V.
Material of the enclosure is polycarbonate.
Greenhouse temperature can be from -15°C to 40°C.
Then I would suggest a temperature control and lookup the required temperature to keep water vapor from condensing at 40deg C. Which means the board will need to be warmer than 40, then you need to check the operating temperature for each component so as to not exceed it.
it would be a lot more energy efficient to simply protect your board against the moisture using a conformal silicone coating.
use a peltier
Inside a plastic enclosure, so it's "watertight" allready right? Have you put your plastic enclosure in the greenhouse already? Is there build-up of any water inside? I know from experience that arduino can have a lot.
I have one outside hanging un a terra cota plant pot, above a watertank where you can feel the warm damp air rise from when it is being filled up.
After 6 months still working and no corrosion to be found.....
Do some testing first
Hi,
Does you control box have to reside inside the greenhouse?
Most units live outside away from the humidity and heat.
Tom... 
Keep the board powered on.
The insulation of the box does the rest, even if there are ventilation openings on the bottom (highly recommended so water can't collect in the box). A spray of conformal coating is also highly recommended.
That's all you need to keep your project 2-3 degrees above ambient, and that in turn is all you need to stop condensation as the humidity inside your box can never reach 100%. Works great for me in a climate where rainstorms and days or even weeks of 95-100% humidity are common.
Ok thanks for your answers! Conformal coating sounds good and I will still put it in the box with a hole at the bottom.