Potential heat problem?

I'm currently in the process of building a custom shell for my arduino remote control project out of cardboard and (the plan is) paper mache. It occurs to me that these are probably moderately good thermal insulation, so I'm wondering if it might be a good idea to drill a few small holes in the vicinity of the voltage regular ICs to provide a bit of ventilation?

You can see the design evolving here:

http://home.comcast.net/~tomhorsley/hardware/arduino/physical.html

What is the Arduino doing? What environment will it be operating in? What is attached to it? How is the Arduino powered?

Generally, the Arduino itself does not get very warm, unless it is powered by a high voltage power supply.

Right. I should have mentioned that I'll be running it from a 9 Volt wall wart. I have noticed that it gets ever so slightly warm near the power socket when I use the wall wart to run it, so I wondered if the heat might build up in an enclosed shell. Mostly it will be sitting on a shelf waiting to get commands via the bluetooth shield and send IR remote signals out based on the command.

Mostly it will be sitting on a shelf waiting to get commands via the bluetooth shield and send IR remote signals out based on the command.

Then some ventilation holes in the back side should not be too objectionable.

I should have mentioned that I'll be running it from a 9 Volt wall wart.

If you could find a 7.5 volt wall wart, that would keep the temperature a lot cooler.

PaulS:
If you could find a 7.5 volt wall wart, that would keep the temperature a lot cooler.

Yea, I looked for a better voltage, but my vast pile of old wall warts only had 5V, 9V, and 12V to choose from, so 9 was my best bet :-).

but my vast pile of old wall warts only had 5V, 9V, and 12V to choose from, so 9 was my best bet

Might want to think about what the Arduino is worth, relative to the cost of a 7.5V wall wart. But, hey, it's your Arduino.

Claghorn:
my vast pile of old wall warts only had 5V, 9V, and 12V to choose from

You don't have a USB (5V) wall wart in your vast pile ?

You don't have a USB (5V) wall wart in your vast pile ?

That would have to be a regulated 5V, not an unregulated 5V, and you'd have to cut the connector off to wire it past the 5V regulator. Using an unregulated 5V past the voltage regulator is not a good idea, and using the unregulated 5V before the voltage regulator is not enough voltage.

PaulS:
That would have to be a regulated 5V, not an unregulated 5V, and you'd have to cut the connector off to wire it past the 5V regulator.

I'd use an USB cable, and I had assumed anything looking like an active USB-A connector should supply regulated 5V. Am I wrong ?

Using an unregulated 5V past the voltage regulator is not a good idea, and using the unregulated 5V before the voltage regulator is not enough voltage.

Sure.

PaulS:
That would have to be a regulated 5V, not an unregulated 5V, and you'd have to cut the connector off to wire it past the 5V regulator.

I suppose it's possible there are unregulated USB supplies, but I wouldn't have thought that was usual. I would expect to find it was a regulated 5V, and I've got half a dozen or so of various types here that all are.

Given a regulated 5V USB supply, you don't need to cut plug off or bypass anything - just plug into the Arduino and forget about it. You could monitor the Arduino board temperature for a few hours to make sure, but unless you're driving something that is taking a lot of current I wouldn't expect the Arduino to generate enough heat to require cooling ventilation. It's not as if your paper mache shell is going to be a perfect insulator.

michael_x:
I'd use an USB cable, and I had assumed anything looking like an active USB-A connector should supply regulated 5V. Am I wrong ?

I've seen a lot of conflicting reports on the quality of the power provided by USB chargers. I do have a couple of them laying around as well though. Might be the way to go.

Have a couple of holes, one close to the regulator that gets hot and the other as far away as possible. In that way you get a natural convection air flow through the case which is much better at cooling than simply having holes close to the hot thing.