I Would like to have My arduino outdoors. Its kind of a wheather station. But how do i best prepare and mount IT? A plastic Box With holes in it? How about the moist?
Cheers!
When you need weatherproof conditions, things get complicated.
There are a number of factors and questions you need to answer first, eg:
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Heat dissipation: how much heat is produced by your circuit and how are you going to make sure it gets dissipated in the new enclosure. Will you be needing forced ventilation?
Is it just the arduino or other things as well? -
Will you be installing it in completely open terrain in a covered place. i.e covered veranda or car park?
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What is the temperature range it needs to function?
If moisture is an issue, you might need a heater.
Consider the possibility of an enclosure within an enclosure. The first box holds the arduino and allows heat to dissipate out of the box throuh holes, while the second box offers the required IP rating and protects from hash weather.
Boxing it up in a weather-sealed enclosure (i.e. with a sealing rubber gasket) is a good idea - ideally with all penetrations from the bottom. Then invest in some conformal coating for components than can handle it. Or make your own with some epoxy or polyester resin. However, be careful around sensors (humidity, pressure, etc.) and heat sinks - they may or may not tolerate the extra insulation / contamination.
IP6X type of enclosure will water proof your arduino:
Place connections below and use water proof sockets with gaskets and caps for connections not used. Maybe set it under a shade or below your solar panel.
If a circuit is powered it will likely be the warmest thing in the enclosure, so moisture does not tend to condense on it. But the top of the enclosure does tend to be the coolest place at night, so moisture condenses and then drips on the circuit. I put a wicking material on the top of the enclosure to pull the water off to the sides where it can drip. If a wire touches aginst the wick then water can run down the wire to the circuit.
My tinkering thing is using an SLA battery and a solar charge controller which is disabled when bellow zero and above 40 centigrade. The problem is that a discharged SLA battery (e.g. in the morning) is mostly water and can freeze near zero, so the charge controller really needs to be off until it warms above that.
I agree with polycase. I've used them for several projects.
Rather than rely on epoxy, you could order some wire glands that are also waterproof from Polycase. That way you can also remove the wiring easily if you need to change something.
True but unless you close up the case in a low moisture environment, then ambient humidity can condense.
I found this out the hard way with a waterproof camera (LUMIX) that I opened in Florida to put in a fresh battery. I then went swimming in the pool only to find condensate on the inside of the lens. Water had not gotten in, but humid air did.
Desiccant packs may help but sealing the unit up in a low RH environment is an even better bet. However, there goes in field serviceability unless you plan on bringing the enclosure into your car every time you want to service it when it's over 30% RH outside.
I also had a board get all corroded on me thanks to experiments with dry ice - the cold board managed to 'get' a lot of humidity, even out of otherwise relatively dry winter air.
So a better bet may be a shielded / conformal coated PCB.