Using Arduino in direct sunlight

I want to build a self-watering Arduino system similar to the one in this video:

Is there any risk to damage the Adruino board by exposing it to direct sunligt during a long period of time? Should I use a non-transparent box instead to isolate the arduino from the sun?

I don't know of anything on a common Arduino board that sunlight alone would damage.

That's nice, I assumed it would work but as I was a little unsure I wanted to be on the safe side.

Thanks for your reply.

I would be a bit concerned that a clear box would work like a greenhouse or solar heater and get a bit toasty inside. Maybe add a bit of white duct tape to reflect the sun a bit if you use a box like the video

What are you using to power the Arduino? Youll definitely want to shield the box from sunlight (opaque enclosure, reflective tape, etc).

saildude:
I would be a bit concerned that a clear box would work like a greenhouse or solar heater and get a bit toasty inside. Maybe add a bit of white duct tape to reflect the sun a bit if you use a box like the video

Yeah I thought that it would get a little hot. I did some research and found that the Arduino operating temperature ranges from -40 to 85 degrees celcius (source). I like the idea of having an LCD to display information, so that's why I want to use a clear box. Perhaps I could put some white tape on the back of the box as you suggested (the box will be faced so that the sun only hits the back of it).

Moisture from rain or condensation on the board and wiring is a far, far more serious problem than sunlight, and it is extremely difficult to eliminate. Conformal coating helps.

czu001:
What are you using to power the Arduino? Youll definitely want to shield the box from sunlight (opaque enclosure, reflective tape, etc).

I'm using a 12V battery holder since the water pump runs at that voltage. After hearing you guys discussing it, I will definitely protect the arduino from the heat that gets trapped inside the box. Hopefully my electronics will last a litte longer now.

Is it bad for the batteries to be heated up?

jremington:
Moisture from rain or condensation on the board and wiring is a far, far more serious problem than sunlight, and it is extremely difficult to eliminate. Conformal coating helps.

I’m thinking about using this box:

https://www.clasohlson.com/uk/Vattentät-låda-/Pr318543000

It’s water- and dustproof. It also has a rubber closure, so I’m thinking that I can run the wires out of the box without making a hole in it. It looks like the guy in the attached video used that solution, I tink it will be water-safe as long as i pull the wire through the bottom of the box (like in the attached PNG). Thoughts?

wiring.PNG

That enclosure will certainly help, but temperature swings draw in moist air through any openings, and condensation will eventually form on the circuit board.

jremington:
That enclosure will certainly help, but temperature swings draw in moist air through any openings, and condensation will eventually form on the circuit board.

That's a good point, how much of a problem do you think it is? Would you recommend that I buy one of these for example?

Or is there any simplier way of preventing the moist to enter, maybe putting some piece of extra rubber where the wires exits? (I would be glad if I don't have to cover my board with coating, but I will stick with it if it's the best alternative). Do you think I can run the project with just the setup that I described earlier? (with the wires just exiting from the box when it's closed).

DuVetVilkenEmil:
Is there any risk to damage the Adruino board by exposing it to direct sunligt during a long period of time?

The Arduino board itself is probably OK, but it does rather depend where in the World you are.

it does rather depend where in the World you are.

Agreed. Try it and see how long the installation continues to work.

Also pay attention to where advice on this comes from, and compare to your own climate.

For example, many (most?) plants that want "full sunlight" can't hack "full Las Vegas sun."

I've noticed significant changes in color on my sprinkler wires that were exposed to sunlight--enough that I have to find which color is which by trial and error.

Or my 6 mil hothouse sheeting that will break down through several levels if left in our summer sun.

Will it matter if the sun discolors things? If it causes labels to no longer be readable?

Check out the last few posts regarding vents. They work really well for a few bucks. Polycase enclosures are nice but $$$.

Moisture is usually the main problem. I prefer an inverted bucket style container, especially for stuff that's always on and produces some heat. That, plus conformal coating, does wonders in keeping your electronics alive even through tropical rainstorms and typhoons.

For wires that are exposed to the sun, look for UV resistant isolation, or place them in a UV resistant duct. It's the UV that's killing, not the heat. It's also the UV that causes the bleaching of pigments, it chemically breaks them down. Likewise it can chemically break down the cable isolation, making it brittle, then break, and then you have a short. That's why you need UV protection.

Same for the Arduino board itself: it's the UV that may do damage. Note: may! I don't know whether it actually will. Most transparent cases are made out of acrylic or polystyrene, both of which are opaque for UV light under 400 nm. So while you can see your stuff just fine, the UV doesn't pass through.

Batteries will be affected by heat (even more so: cold) but it depends on the type of battery and the extent of the heat whether that's an issue. Check the manufacturer's data sheet for recommendations.

Wow. You linked a seven minute video to ask just that one question? The electronics in the video was obviously custom made by the guy who is using it, with a lot of design and engineering for his specific application. Copy and paste is a good starting point, but considering there are a lot of parameters (humidity, temperature extremes and cycling rates, dissimilar metal contact, material fatigue, etc., in addition to illumination intensity that you brought up), your question seems limited. If I were making this (and it’s pretty cool - my girlfriend does gardening in a ‘high stress environment’ - an urban Sonoran Desert fruit and flower garden), I would make a trial version, and closely monitor failures and near failures to make corrections for next year’s version. It might take a couple tries before discovering all of the weaknesses of the design.

To begin with, I want to thank you all for your interesting inputs. I never expected this much activity on my post, but I am more than thankful.

I will write a short reply to all the answers I got:

srnet:
The Arduino board itself is probably OK, but it does rather depend where in the World you are.

That’s a good point as weather conditions are not the same all over the world. Different climates has different impacts on the hardware.

jremington:
Agreed. Try it and see how long the installation continues to work.

Sounds like a good advice, the components aren’t that expensive so I guess I could just test it and readjust accordingly to the results.

dochawk:
Also pay attention to where advice on this comes from, and compare to your own climate.

For example, many (most?) plants that want "full sunlight" can't hack "full Las Vegas sun."

I've noticed significant changes in color on my sprinkler wires that were exposed to sunlight--enough that I have to find which color is which by trial and error.

Or my 6 mil hothouse sheeting that will break down through several levels if left in our summer sun.

Will it matter if the sun discolors things? If it causes labels to no longer be readable?

Interesting input, maybe it doesn't matter if some of my equipment gets affected by the sun. I think that the advice jremington gave was very good, I can test what works and find solutions accordingly.

czu001:
Polycase Condensation Outdoors - Project Guidance - Arduino Forum

Check out the last few posts regarding vents. They work really well for a few bucks. Polycase enclosures are nice but $$$.

I read the entire discussion and found it very interesting, thank you for sharing the link. I have bought the case now and will do some testing to see if I need a vent, but if I do I know where to find them. Thanks!

wvmarle:
Moisture is usually the main problem. I prefer an inverted bucket style container, especially for stuff that's always on and produces some heat. That, plus conformal coating, does wonders in keeping your electronics alive even through tropical rainstorms and typhoons.

For wires that are exposed to the sun, look for UV resistant isolation, or place them in a UV resistant duct. It's the UV that's killing, not the heat. It's also the UV that causes the bleaching of pigments, it chemically breaks them down. Likewise it can chemically break down the cable isolation, making it brittle, then break, and then you have a short. That's why you need UV protection.

Same for the Arduino board itself: it's the UV that may do damage. Note: may! I don't know whether it actually will. Most transparent cases are made out of acrylic or polystyrene, both of which are opaque for UV light under 400 nm. So while you can see your stuff just fine, the UV doesn't pass through.

Batteries will be affected by heat (even more so: cold) but it depends on the type of battery and the extent of the heat whether that's an issue. Check the manufacturer's data sheet for recommendations.

A lot of information, thank you for putting the time in! I didn’t know that it was the UV to look out for, good that you said that. I will read what the manufacturers say about the batteries. I think I will make a “test-setup” and see which results I get, and then find new solutions if I come across any problems. Thanks for sharing!

ChrisTenone:
Wow. You linked a seven minute video to ask just that one question? The electronics in the video was obviously custom made by the guy who is using it, with a lot of design and engineering for his specific application. Copy and paste is a good starting point, but considering there are a lot of parameters (humidity, temperature extremes and cycling rates, dissimilar metal contact, material fatigue, etc., in addition to illumination intensity that you brought up), your question seems limited. If I were making this (and it's pretty cool - my girlfriend does gardening in a 'high stress environment' - an urban Sonoran Desert fruit and flower garden), I would make a trial version, and closely monitor failures and near failures to make corrections for next year's version. It might take a couple tries before discovering all of the weaknesses of the design.

I was never going to copy and paste his design. I’m sorry if I was a little unclear, but I want to make a similar setup. I just wanted you to have something as a reference to better understand what I meant with the waterproof case. But you’re bringing up a good point that I agree with: copy and paste can be good for learning purposes, but it’s problematic when you want to build bigger projects (and especially if they are affected by the climate). And your girlfriends project sounds cool! I think I will do a “trial version” as you suggested, and then note the errors to improve the system.

And again, I want to thank you all for your interesting inputs on the project. I’m really grateful for all of you who took the time to reply. It really means a lot!

And also, feel free to keep commenting on this post if you have any more inputs/ideas. I will keep replying.

Have a great day!

I have bought the case now and will do some testing to see if I need a vent

You’ll need something :slight_smile: Inverted bucket, vent, and conformal coating/protection. I use this stuff Corrosion X.

I was recommended to use Corrosion X from another forum, and let me tell you it works really well. My only issue with conformal coating is you have to be careful what you coat (buttons, possibly trace antennas, etc.). I think others have discussed Corrosion X on here, too.

Break apart a solar light and you’ll see there are holes milled on the bottom of the enclosure.

Keep us posted!

czu001:
You'll need something :slight_smile: Inverted bucket, vent, and conformal coating/protection. I use this stuff Corrosion X.

I was recommended to use Corrosion X from another forum, and let me tell you it works really well. My only issue with conformal coating is you have to be careful what you coat (buttons, possibly trace antennas, etc.). I think others have discussed Corrosion X on here, too.

Break apart a solar light and you'll see there are holes milled on the bottom of the enclosure.

Keep us posted!

Thanks for the tip! As you say, I think I will need to get some sort of conformal coating sooner or later. Great to hear that you have had succes with it.
I found what you said about solar lights vety interesting, I will look for it if I ever come across a broken one.

Thanks for sharing your experience, I will keep you updated!